@charset "UTF-8";
/* ==========================================================================
   دليل السيو الشامل — Technical Reference System
   Register: product / documentation. 98 pages of dense Arabic reference prose.
   Colour: white ground, true-black ink, one saturated signal blue.
   Structure carries the design: hard rules, strict scale, mono metadata.
   Direction: RTL-native — zero physical left/right properties.
   ========================================================================== */

/* --------------------------------------------------------------------------
   0. Fonts — self-hosted. No request leaves this origin.
   Arabic + Latin + Latin-Ext subsets only; unicode-range means the browser
   downloads just the ranges a page actually uses.
   -------------------------------------------------------------------------- */

/* latin-ext */
@font-face {
  font-family: 'IBM Plex Mono';
  font-style: normal;
  font-weight: 400;
  font-display: swap;
  src: url(fonts/ibm-plex-mono-400-latin-ext.woff2) format('woff2');
  unicode-range: U+0100-02BA, U+02BD-02C5, U+02C7-02CC, U+02CE-02D7, U+02DD-02FF, U+0304, U+0308, U+0329, U+1D00-1DBF, U+1E00-1E9F, U+1EF2-1EFF, U+2020, U+20A0-20AB, U+20AD-20C0, U+2113, U+2C60-2C7F, U+A720-A7FF;
}
/* latin */
@font-face {
  font-family: 'IBM Plex Mono';
  font-style: normal;
  font-weight: 400;
  font-display: swap;
  src: url(fonts/ibm-plex-mono-400-latin.woff2) format('woff2');
  unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
}
/* latin-ext */
@font-face {
  font-family: 'IBM Plex Mono';
  font-style: normal;
  font-weight: 500;
  font-display: swap;
  src: url(fonts/ibm-plex-mono-500-latin-ext.woff2) format('woff2');
  unicode-range: U+0100-02BA, U+02BD-02C5, U+02C7-02CC, U+02CE-02D7, U+02DD-02FF, U+0304, U+0308, U+0329, U+1D00-1DBF, U+1E00-1E9F, U+1EF2-1EFF, U+2020, U+20A0-20AB, U+20AD-20C0, U+2113, U+2C60-2C7F, U+A720-A7FF;
}
/* latin */
@font-face {
  font-family: 'IBM Plex Mono';
  font-style: normal;
  font-weight: 500;
  font-display: swap;
  src: url(fonts/ibm-plex-mono-500-latin.woff2) format('woff2');
  unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
}
/* arabic */
@font-face {
  font-family: 'IBM Plex Sans Arabic';
  font-style: normal;
  font-weight: 400;
  font-display: swap;
  src: url(fonts/ibm-plex-sans-arabic-400-arabic.woff2) format('woff2');
  unicode-range: U+0600-06FF, U+0750-077F, U+0870-088E, U+0890-0891, U+0897-08E1, U+08E3-08FF, U+200C-200E, U+2010-2011, U+204F, U+2E41, U+FB50-FDFF, U+FE70-FE74, U+FE76-FEFC, U+102E0-102FB, U+10E60-10E7E, U+10EC2-10EC4, U+10EFC-10EFF, U+1EE00-1EE03, U+1EE05-1EE1F, U+1EE21-1EE22, U+1EE24, U+1EE27, U+1EE29-1EE32, U+1EE34-1EE37, U+1EE39, U+1EE3B, U+1EE42, U+1EE47, U+1EE49, U+1EE4B, U+1EE4D-1EE4F, U+1EE51-1EE52, U+1EE54, U+1EE57, U+1EE59, U+1EE5B, U+1EE5D, U+1EE5F, U+1EE61-1EE62, U+1EE64, U+1EE67-1EE6A, U+1EE6C-1EE72, U+1EE74-1EE77, U+1EE79-1EE7C, U+1EE7E, U+1EE80-1EE89, U+1EE8B-1EE9B, U+1EEA1-1EEA3, U+1EEA5-1EEA9, U+1EEAB-1EEBB, U+1EEF0-1EEF1;
}
/* latin-ext */
@font-face {
  font-family: 'IBM Plex Sans Arabic';
  font-style: normal;
  font-weight: 400;
  font-display: swap;
  src: url(fonts/ibm-plex-sans-arabic-400-latin-ext.woff2) format('woff2');
  unicode-range: U+0100-02BA, U+02BD-02C5, U+02C7-02CC, U+02CE-02D7, U+02DD-02FF, U+0304, U+0308, U+0329, U+1D00-1DBF, U+1E00-1E9F, U+1EF2-1EFF, U+2020, U+20A0-20AB, U+20AD-20C0, U+2113, U+2C60-2C7F, U+A720-A7FF;
}
/* latin */
@font-face {
  font-family: 'IBM Plex Sans Arabic';
  font-style: normal;
  font-weight: 400;
  font-display: swap;
  src: url(fonts/ibm-plex-sans-arabic-400-latin.woff2) format('woff2');
  unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
}
/* arabic */
@font-face {
  font-family: 'IBM Plex Sans Arabic';
  font-style: normal;
  font-weight: 500;
  font-display: swap;
  src: url(fonts/ibm-plex-sans-arabic-500-arabic.woff2) format('woff2');
  unicode-range: U+0600-06FF, U+0750-077F, U+0870-088E, U+0890-0891, U+0897-08E1, U+08E3-08FF, U+200C-200E, U+2010-2011, U+204F, U+2E41, U+FB50-FDFF, U+FE70-FE74, U+FE76-FEFC, U+102E0-102FB, U+10E60-10E7E, U+10EC2-10EC4, U+10EFC-10EFF, U+1EE00-1EE03, U+1EE05-1EE1F, U+1EE21-1EE22, U+1EE24, U+1EE27, U+1EE29-1EE32, U+1EE34-1EE37, U+1EE39, U+1EE3B, U+1EE42, U+1EE47, U+1EE49, U+1EE4B, U+1EE4D-1EE4F, U+1EE51-1EE52, U+1EE54, U+1EE57, U+1EE59, U+1EE5B, U+1EE5D, U+1EE5F, U+1EE61-1EE62, U+1EE64, U+1EE67-1EE6A, U+1EE6C-1EE72, U+1EE74-1EE77, U+1EE79-1EE7C, U+1EE7E, U+1EE80-1EE89, U+1EE8B-1EE9B, U+1EEA1-1EEA3, U+1EEA5-1EEA9, U+1EEAB-1EEBB, U+1EEF0-1EEF1;
}
/* latin-ext */
@font-face {
  font-family: 'IBM Plex Sans Arabic';
  font-style: normal;
  font-weight: 500;
  font-display: swap;
  src: url(fonts/ibm-plex-sans-arabic-500-latin-ext.woff2) format('woff2');
  unicode-range: U+0100-02BA, U+02BD-02C5, U+02C7-02CC, U+02CE-02D7, U+02DD-02FF, U+0304, U+0308, U+0329, U+1D00-1DBF, U+1E00-1E9F, U+1EF2-1EFF, U+2020, U+20A0-20AB, U+20AD-20C0, U+2113, U+2C60-2C7F, U+A720-A7FF;
}
/* latin */
@font-face {
  font-family: 'IBM Plex Sans Arabic';
  font-style: normal;
  font-weight: 500;
  font-display: swap;
  src: url(fonts/ibm-plex-sans-arabic-500-latin.woff2) format('woff2');
  unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
}
/* arabic */
@font-face {
  font-family: 'IBM Plex Sans Arabic';
  font-style: normal;
  font-weight: 600;
  font-display: swap;
  src: url(fonts/ibm-plex-sans-arabic-600-arabic.woff2) format('woff2');
  unicode-range: U+0600-06FF, U+0750-077F, U+0870-088E, U+0890-0891, U+0897-08E1, U+08E3-08FF, U+200C-200E, U+2010-2011, U+204F, U+2E41, U+FB50-FDFF, U+FE70-FE74, U+FE76-FEFC, U+102E0-102FB, U+10E60-10E7E, U+10EC2-10EC4, U+10EFC-10EFF, U+1EE00-1EE03, U+1EE05-1EE1F, U+1EE21-1EE22, U+1EE24, U+1EE27, U+1EE29-1EE32, U+1EE34-1EE37, U+1EE39, U+1EE3B, U+1EE42, U+1EE47, U+1EE49, U+1EE4B, U+1EE4D-1EE4F, U+1EE51-1EE52, U+1EE54, U+1EE57, U+1EE59, U+1EE5B, U+1EE5D, U+1EE5F, U+1EE61-1EE62, U+1EE64, U+1EE67-1EE6A, U+1EE6C-1EE72, U+1EE74-1EE77, U+1EE79-1EE7C, U+1EE7E, U+1EE80-1EE89, U+1EE8B-1EE9B, U+1EEA1-1EEA3, U+1EEA5-1EEA9, U+1EEAB-1EEBB, U+1EEF0-1EEF1;
}
/* latin-ext */
@font-face {
  font-family: 'IBM Plex Sans Arabic';
  font-style: normal;
  font-weight: 600;
  font-display: swap;
  src: url(fonts/ibm-plex-sans-arabic-600-latin-ext.woff2) format('woff2');
  unicode-range: U+0100-02BA, U+02BD-02C5, U+02C7-02CC, U+02CE-02D7, U+02DD-02FF, U+0304, U+0308, U+0329, U+1D00-1DBF, U+1E00-1E9F, U+1EF2-1EFF, U+2020, U+20A0-20AB, U+20AD-20C0, U+2113, U+2C60-2C7F, U+A720-A7FF;
}
/* latin */
@font-face {
  font-family: 'IBM Plex Sans Arabic';
  font-style: normal;
  font-weight: 600;
  font-display: swap;
  src: url(fonts/ibm-plex-sans-arabic-600-latin.woff2) format('woff2');
  unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
}
/* arabic */
@font-face {
  font-family: 'IBM Plex Sans Arabic';
  font-style: normal;
  font-weight: 700;
  font-display: swap;
  src: url(fonts/ibm-plex-sans-arabic-700-arabic.woff2) format('woff2');
  unicode-range: U+0600-06FF, U+0750-077F, U+0870-088E, U+0890-0891, U+0897-08E1, U+08E3-08FF, U+200C-200E, U+2010-2011, U+204F, U+2E41, U+FB50-FDFF, U+FE70-FE74, U+FE76-FEFC, U+102E0-102FB, U+10E60-10E7E, U+10EC2-10EC4, U+10EFC-10EFF, U+1EE00-1EE03, U+1EE05-1EE1F, U+1EE21-1EE22, U+1EE24, U+1EE27, U+1EE29-1EE32, U+1EE34-1EE37, U+1EE39, U+1EE3B, U+1EE42, U+1EE47, U+1EE49, U+1EE4B, U+1EE4D-1EE4F, U+1EE51-1EE52, U+1EE54, U+1EE57, U+1EE59, U+1EE5B, U+1EE5D, U+1EE5F, U+1EE61-1EE62, U+1EE64, U+1EE67-1EE6A, U+1EE6C-1EE72, U+1EE74-1EE77, U+1EE79-1EE7C, U+1EE7E, U+1EE80-1EE89, U+1EE8B-1EE9B, U+1EEA1-1EEA3, U+1EEA5-1EEA9, U+1EEAB-1EEBB, U+1EEF0-1EEF1;
}
/* latin-ext */
@font-face {
  font-family: 'IBM Plex Sans Arabic';
  font-style: normal;
  font-weight: 700;
  font-display: swap;
  src: url(fonts/ibm-plex-sans-arabic-700-latin-ext.woff2) format('woff2');
  unicode-range: U+0100-02BA, U+02BD-02C5, U+02C7-02CC, U+02CE-02D7, U+02DD-02FF, U+0304, U+0308, U+0329, U+1D00-1DBF, U+1E00-1E9F, U+1EF2-1EFF, U+2020, U+20A0-20AB, U+20AD-20C0, U+2113, U+2C60-2C7F, U+A720-A7FF;
}
/* latin */
@font-face {
  font-family: 'IBM Plex Sans Arabic';
  font-style: normal;
  font-weight: 700;
  font-display: swap;
  src: url(fonts/ibm-plex-sans-arabic-700-latin.woff2) format('woff2');
  unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
}

/* --------------------------------------------------------------------------
   1. Tokens
   -------------------------------------------------------------------------- */

:root {
  color-scheme: light dark;

  /* Ground */
  --paper:        oklch(100%  0     0);
  --panel:        oklch(97%   0.003 264);
  --sunken:       oklch(94.2% 0.005 258);
  --rule:         oklch(90.9% 0.006 264);
  --rule-strong:  oklch(82.9% 0.011 262);

  /* Ink */
  --ink:          oklch(15%   0.002 286);
  --ink-body:     oklch(33.2% 0.011 264);
  --ink-muted:    oklch(48.5% 0.012 267);
  --ink-faint:    oklch(61.3% 0.014 267);

  /* Signal — one accent, used only for interaction and current position */
  --accent:       oklch(49.5% 0.199 261);
  --accent-hover: oklch(40.9% 0.163 261);
  --accent-tint:  oklch(95.6% 0.018 261);
  --accent-line:  oklch(88.3% 0.049 258);
  --on-accent:    oklch(100%  0     0);

  /* Semantic — same lightness band as the accent so they sit level with it */
  --info:         oklch(49.5% 0.199 261);
  --info-bg:      oklch(95.6% 0.018 261);
  --info-line:    oklch(88.3% 0.049 258);
  --success:      oklch(51.8% 0.133 152);
  --success-bg:   oklch(96%   0.020 152);
  --success-line: oklch(88%   0.050 152);
  --warning:      oklch(53.1% 0.119 65);
  --warning-bg:   oklch(96.5% 0.022 70);
  --warning-line: oklch(89%   0.055 70);
  --danger:       oklch(50.1% 0.178 29);
  --danger-bg:    oklch(96%   0.020 29);
  --danger-line:  oklch(89%   0.048 29);

  /* Code */
  --code-bg:      oklch(96%   0.004 264);
  --code-ink:     oklch(35%   0.120 300);
  --block-bg:     oklch(15%   0.002 286);
  --block-ink:    oklch(91%   0.006 264);

  /* Type */
  --sans: "IBM Plex Sans Arabic", "Segoe UI", system-ui, -apple-system, sans-serif;
  --mono: "IBM Plex Mono", ui-monospace, "SFMono-Regular", "Cascadia Code", monospace;

  --t-xs:   0.75rem;
  --t-sm:   0.8125rem;
  --t-md:   0.9375rem;
  --t-base: 1.0625rem;
  --t-lg:   1.1875rem;
  --t-h4:   1.0625rem;
  --t-h3:   1.25rem;
  --t-h2:   clamp(1.35rem, 2.2vw, 1.6rem);
  --t-h1:   clamp(1.75rem, 3vw, 2.125rem);
  --t-disp: clamp(2rem, 4vw, 2.75rem);

  --lead-tight: 1.22;
  --lead-body:  1.85;
  --measure: 100%;
  --column: 48rem;

  /* Space — 4px base */
  --s1: 0.25rem;  --s2: 0.5rem;   --s3: 0.75rem;  --s4: 1rem;
  --s5: 1.5rem;   --s6: 2rem;     --s7: 2.75rem;  --s8: 4rem;   --s9: 6rem;

  /* Radius — minimal; this system leans on rules, not roundness */
  --r-sm: 3px;  --r-md: 5px;  --r-lg: 8px;  --r-full: 999px;

  --shadow-float:  0 1px 2px oklch(15% 0.002 286 / 0.08), 0 8px 24px oklch(15% 0.002 286 / 0.10);
  --shadow-drawer: -12px 0 40px oklch(15% 0.002 286 / 0.18);

  --ease: cubic-bezier(0.2, 0, 0, 1);
  --d1: 120ms;  --d2: 200ms;  --d3: 300ms;

  --sidebar-w: 17rem;
  --header-h: 3.25rem;
}

/* Dark: a true inversion. Ground never goes pure black; ink never pure white. */
[data-theme="dark"] {
  --paper:        oklch(16%   0.008 264);
  --panel:        oklch(20%   0.010 264);
  --sunken:       oklch(24%   0.012 264);
  --rule:         oklch(29%   0.013 264);
  --rule-strong:  oklch(40%   0.016 264);

  --ink:          oklch(97%   0.003 264);
  --ink-body:     oklch(88%   0.006 264);
  --ink-muted:    oklch(72%   0.011 267);
  --ink-faint:    oklch(58%   0.013 267);

  --accent:       oklch(76%   0.140 250);
  --accent-hover: oklch(85%   0.105 250);
  --accent-tint:  oklch(27%   0.070 258);
  --accent-line:  oklch(38%   0.100 258);
  --on-accent:    oklch(14%   0.020 260);

  --info:         oklch(76%   0.140 250);
  --info-bg:      oklch(27%   0.070 258);
  --info-line:    oklch(38%   0.100 258);
  --success:      oklch(78%   0.135 155);
  --success-bg:   oklch(26%   0.060 155);
  --success-line: oklch(37%   0.090 155);
  --warning:      oklch(81%   0.125 72);
  --warning-bg:   oklch(28%   0.060 68);
  --warning-line: oklch(39%   0.090 68);
  --danger:       oklch(75%   0.135 29);
  --danger-bg:    oklch(27%   0.070 29);
  --danger-line:  oklch(38%   0.100 29);

  --code-bg:      oklch(24%   0.014 264);
  --code-ink:     oklch(84%   0.100 300);
  --block-bg:     oklch(11.5% 0.008 264);
  --block-ink:    oklch(90%   0.006 264);

  --shadow-float:  0 1px 2px oklch(0% 0 0 / 0.4), 0 8px 24px oklch(0% 0 0 / 0.45);
  --shadow-drawer: -12px 0 40px oklch(0% 0 0 / 0.55);
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --paper:        oklch(16%   0.008 264);
    --panel:        oklch(20%   0.010 264);
    --sunken:       oklch(24%   0.012 264);
    --rule:         oklch(29%   0.013 264);
    --rule-strong:  oklch(40%   0.016 264);
    --ink:          oklch(97%   0.003 264);
    --ink-body:     oklch(88%   0.006 264);
    --ink-muted:    oklch(72%   0.011 267);
    --ink-faint:    oklch(58%   0.013 267);
    --accent:       oklch(76%   0.140 250);
    --accent-hover: oklch(85%   0.105 250);
    --accent-tint:  oklch(27%   0.070 258);
    --accent-line:  oklch(38%   0.100 258);
    --on-accent:    oklch(14%   0.020 260);
    --info:         oklch(76%   0.140 250);
    --info-bg:      oklch(27%   0.070 258);
    --info-line:    oklch(38%   0.100 258);
    --success:      oklch(78%   0.135 155);
    --success-bg:   oklch(26%   0.060 155);
    --success-line: oklch(37%   0.090 155);
    --warning:      oklch(81%   0.125 72);
    --warning-bg:   oklch(28%   0.060 68);
    --warning-line: oklch(39%   0.090 68);
    --danger:       oklch(75%   0.135 29);
    --danger-bg:    oklch(27%   0.070 29);
    --danger-line:  oklch(38%   0.100 29);
    --code-bg:      oklch(24%   0.014 264);
    --code-ink:     oklch(84%   0.100 300);
    --block-bg:     oklch(11.5% 0.008 264);
    --block-ink:    oklch(90%   0.006 264);
    --shadow-float:  0 1px 2px oklch(0% 0 0 / 0.4), 0 8px 24px oklch(0% 0 0 / 0.45);
    --shadow-drawer: -12px 0 40px oklch(0% 0 0 / 0.55);
  }
}

/* --------------------------------------------------------------------------
   0b. Fallback palette for engines without oklch() support.
   Without this the entire colour system evaluates to invalid and is dropped,
   which renders the site unstyled rather than merely off-brand.
   -------------------------------------------------------------------------- */

@supports not (color: oklch(0% 0 0)) {
  :root {
    --paper: #FFFFFF;
    --panel: #F4F5F7;
    --sunken: #EAECEF;
    --rule: #DFE1E5;
    --rule-strong: #C3C7CE;
    --ink: #0B0B0C;
    --ink-body: #33363C;
    --ink-muted: #5C5F66;
    --ink-faint: #80848D;
    --accent: #1057D0;
    --accent-hover: #0A42A0;
    --accent-tint: #EAF1FD;
    --accent-line: #C5DAF9;
    --on-accent: #FFFFFF;
    --info: #1057D0;
    --info-bg: #EAF1FD;
    --info-line: #C5DAF9;
    --success: #0A7D3F;
    --success-bg: #E8F6EB;
    --success-line: #C0E2C8;
    --warning: #9A5B00;
    --warning-bg: #FDF1E4;
    --warning-line: #F3D5B4;
    --danger: #B3261D;
    --danger-bg: #FFEDEA;
    --danger-line: #F9D0C9;
    --code-bg: #F0F2F4;
    --code-ink: #45266E;
    --block-bg: #0B0B0C;
    --block-ink: #DFE1E5;
  }

  [data-theme="dark"] {
    --paper: #0B0D11;
    --panel: #14161B;
    --sunken: #1C1F25;
    --rule: #282B32;
    --rule-strong: #434851;
    --ink: #F4F5F7;
    --ink-body: #D5D7DB;
    --ink-muted: #A1A4AC;
    --ink-faint: #777A82;
    --accent: #66B6FF;
    --accent-hover: #98D3FF;
    --accent-tint: #0E2648;
    --accent-line: #1D4176;
    --on-accent: #050911;
    --info: #66B6FF;
    --info-bg: #0E2648;
    --info-line: #1D4176;
    --success: #67D191;
    --success-bg: #042C17;
    --success-line: #034D2A;
    --warning: #F3B35F;
    --warning-bg: #3C2201;
    --warning-line: #643A00;
    --danger: #F78B7C;
    --danger-bg: #421611;
    --danger-line: #6E2921;
    --code-bg: #1C1F26;
    --code-ink: #D4BCFF;
    --block-bg: #040507;
    --block-ink: #DCDEE2;
  }

  @media (prefers-color-scheme: dark) {
    :root:not([data-theme="light"]) {
      --paper: #0B0D11;
      --panel: #14161B;
      --sunken: #1C1F25;
      --rule: #282B32;
      --rule-strong: #434851;
      --ink: #F4F5F7;
      --ink-body: #D5D7DB;
      --ink-muted: #A1A4AC;
      --ink-faint: #777A82;
      --accent: #66B6FF;
      --accent-hover: #98D3FF;
      --accent-tint: #0E2648;
      --accent-line: #1D4176;
      --on-accent: #050911;
      --info: #66B6FF;
      --info-bg: #0E2648;
      --info-line: #1D4176;
      --success: #67D191;
      --success-bg: #042C17;
      --success-line: #034D2A;
      --warning: #F3B35F;
      --warning-bg: #3C2201;
      --warning-line: #643A00;
      --danger: #F78B7C;
      --danger-bg: #421611;
      --danger-line: #6E2921;
      --code-bg: #1C1F26;
      --code-ink: #D4BCFF;
      --block-bg: #040507;
      --block-ink: #DCDEE2;
    }
  }
}

/* --------------------------------------------------------------------------
   2. Reset and base
   -------------------------------------------------------------------------- */

*, *::before, *::after { box-sizing: border-box; }
* { margin: 0; }

html {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-block-start: calc(var(--header-h) + var(--s4));
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--sans);
  font-size: var(--t-base);
  line-height: var(--lead-body);
  color: var(--ink-body);
  background: var(--paper);
  min-height: 100svh;
  overflow-x: hidden;
  font-feature-settings: "kern", "liga";
}

img, svg, video { max-width: 100%; height: auto; display: block; }
svg { flex-shrink: 0; }
::selection { background: var(--accent-tint); color: var(--ink); }

:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; border-radius: var(--r-sm); }
:focus:not(:focus-visible) { outline: none; }

/* --------------------------------------------------------------------------
   3. Typography
   -------------------------------------------------------------------------- */

h1, h2, h3, h4, h5, h6 {
  color: var(--ink);
  line-height: var(--lead-tight);
  text-wrap: balance;
  font-weight: 600;
  letter-spacing: -0.015em;
}
h1 { font-size: var(--t-h1); font-weight: 700; letter-spacing: -0.03em; }
h2 { font-size: var(--t-h2); font-weight: 650; letter-spacing: -0.022em; }
h3 { font-size: var(--t-h3); }
h4 { font-size: var(--t-h4); }
h5, h6 { font-size: var(--t-base); }

p { margin-block-end: var(--s4); max-width: var(--measure); text-wrap: pretty; }
p:last-child { margin-block-end: 0; }

strong, b { font-weight: 600; color: var(--ink); }
em { font-style: normal; font-weight: 500; color: var(--ink); }
small { font-size: var(--t-sm); color: var(--ink-muted); }

a {
  color: var(--accent);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 0.2em;
  text-decoration-color: var(--accent-line);
  transition: color var(--d1) var(--ease), text-decoration-color var(--d1) var(--ease);
}
a:hover { color: var(--accent-hover); text-decoration-color: currentColor; }

hr { border: 0; block-size: 1px; background: var(--rule); margin-block: var(--s7); }

ul, ol { margin-block-end: var(--s4); padding-inline-start: var(--s5); max-width: var(--measure); }
ul { list-style: none; }
ul > li { position: relative; }
ul > li::before {
  content: "";
  position: absolute;
  inset-inline-start: calc(var(--s5) * -1 + 0.4rem);
  inset-block-start: 0.85em;
  inline-size: 4px; block-size: 4px;
  background: var(--accent);
}
ol { list-style: decimal; }
li::marker { color: var(--ink-faint); font-variant-numeric: tabular-nums; }
li { margin-block-end: var(--s2); line-height: var(--lead-body); }
li:last-child { margin-block-end: 0; }
li > ul, li > ol { margin-block: var(--s2) 0; }

blockquote {
  margin-block: var(--s6);
  padding: var(--s5);
  background: var(--panel);
  border: 1px solid var(--rule);
  color: var(--ink);
  font-size: var(--t-lg);
  line-height: 1.7;
  max-width: var(--measure);
}
blockquote p { max-width: none; }

/* --------------------------------------------------------------------------
   4. Code
   -------------------------------------------------------------------------- */

code, kbd, samp { font-family: var(--mono); font-size: 0.86em; direction: ltr; unicode-bidi: isolate; }

:not(pre) > code {
  background: var(--code-bg);
  color: var(--code-ink);
  padding: 0.1em 0.35em;
  border: 1px solid var(--rule);
  border-radius: var(--r-sm);
  white-space: nowrap;
}

pre, .code-block {
  background: var(--block-bg);
  color: var(--block-ink);
  padding: var(--s5);
  border-radius: var(--r-md);
  overflow-x: auto;
  margin-block: var(--s5);
  direction: ltr;
  text-align: left;
  font-family: var(--mono);
  font-size: var(--t-sm);
  line-height: 1.7;
  tab-size: 2;
  position: relative;
  scrollbar-width: thin;
}
pre > code { background: none; border: 0; padding: 0; color: inherit; font-size: inherit; white-space: pre; }

.code-copy {
  position: absolute;
  inset-block-start: var(--s3);
  inset-inline-end: var(--s3);
  font-family: var(--sans);
  font-size: var(--t-xs);
  font-weight: 500;
  color: oklch(80% 0.006 264);
  background: oklch(100% 0 0 / 0.08);
  border: 1px solid oklch(100% 0 0 / 0.16);
  border-radius: var(--r-sm);
  padding: 0.25rem 0.55rem;
  cursor: pointer;
  opacity: 0;
  transition: opacity var(--d2) var(--ease), background-color var(--d1) var(--ease);
}
pre:hover .code-copy, .code-block:hover .code-copy, .code-copy:focus-visible { opacity: 1; }
.code-copy:hover { background: oklch(100% 0 0 / 0.16); color: oklch(98% 0 0); }
.code-copy[data-copied="true"] { opacity: 1; color: var(--success); }

/* --------------------------------------------------------------------------
   5. Shell
   -------------------------------------------------------------------------- */

.page-wrapper { display: flex; min-height: 100svh; }

.skip-link {
  position: absolute;
  inset-block-start: var(--s2);
  inset-inline-start: var(--s2);
  z-index: 2000;
  background: var(--accent);
  color: var(--on-accent);
  padding: var(--s2) var(--s4);
  border-radius: var(--r-md);
  font-size: var(--t-sm);
  font-weight: 600;
  text-decoration: none;
  transform: translateY(-200%);
  transition: transform var(--d2) var(--ease);
}
.skip-link:focus { transform: translateY(0); color: var(--on-accent); }

/* Sidebar — pure navigation. The brand now lives in the header. */
.sidebar {
  position: fixed;
  inset-block: 0;
  inset-inline-start: 0;
  inline-size: var(--sidebar-w);
  padding-block-start: var(--header-h);
  background: var(--paper);
  border-inline-end: 1px solid var(--rule);
  z-index: 1000;
  overflow-y: auto;
  overscroll-behavior: contain;
  scrollbar-width: thin;
  transition: transform var(--d3) var(--ease);
}
.sidebar.closed { transform: translateX(100%); }
[dir="ltr"] .sidebar.closed { transform: translateX(-100%); }

.sidebar-nav { padding: var(--s5) var(--s4) var(--s8); }
.sidebar-nav ul { list-style: none; margin: 0 0 var(--s5); padding: 0; max-width: none; }
.sidebar-nav ul:last-child { margin-block-end: 0; }
.sidebar-nav li { margin: 0; }
.sidebar-nav li::before { content: none; }

/* Group label — the structure that was missing */
.nav-group {
  font-family: var(--mono);
  font-size: var(--t-xs);
  font-weight: 500;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--ink-faint);
  margin: 0 0 var(--s2);
  padding-inline-start: var(--s2);
  max-width: none;
}
.nav-group + ul { margin-block-end: var(--s5); }

.sidebar-nav a {
  display: flex;
  align-items: baseline;
  gap: var(--s3);
  padding: 0.34rem var(--s2);
  color: var(--ink-body);
  font-size: var(--t-md);
  font-weight: 400;
  line-height: 1.5;
  text-decoration: none;
  border-radius: var(--r-sm);
  transition: color var(--d1) var(--ease), background-color var(--d1) var(--ease);
}
.sidebar-nav a:hover { color: var(--ink); background: var(--panel); }
.sidebar-nav a.active { color: var(--accent); font-weight: 600; background: var(--accent-tint); }

.nav-index {
  font-family: var(--mono);
  font-size: var(--t-xs);
  color: var(--ink-faint);
  font-variant-numeric: tabular-nums;
  min-inline-size: 1.5em;
  flex-shrink: 0;
}
.sidebar-nav a.active .nav-index { color: var(--accent); }
.nav-count {
  margin-inline-start: auto;
  font-family: var(--mono);
  font-size: var(--t-xs);
  line-height: 1;
  color: var(--ink-faint);
  background: var(--panel);
  border: 1px solid var(--rule);
  border-radius: var(--r-full);
  padding: 0.1rem 0.4rem;
  flex-shrink: 0;
}
.sidebar-nav a.active .nav-count { color: var(--accent); border-color: var(--accent-line); background: var(--paper); }

/* Sub-pages of the chapter you are currently reading */
.nav-sub {
  margin: var(--s1) 0 var(--s2) !important;
  padding-inline-start: calc(1.5em + var(--s3)) !important;
  position: relative;
}
.nav-sub::before {
  content: "";
  position: absolute;
  inset-inline-start: calc(0.75em + var(--s2));
  inset-block: 0.15rem;
  inline-size: 1px;
  background: var(--rule);
}
.nav-sub a {
  display: block;
  padding: 0.26rem var(--s2);
  font-size: var(--t-sm);
  line-height: 1.45;
  color: var(--ink-muted);
  text-wrap: pretty;
}
.nav-sub a:hover { color: var(--ink); }
.nav-sub a.active { color: var(--accent); font-weight: 600; background: var(--accent-tint); }
.nav-sub.is-long { max-block-size: 22rem; overflow-y: auto; scrollbar-width: thin; }

.sidebar-backdrop {
  position: fixed;
  inset: 0;
  background: oklch(15% 0.002 286 / 0.4);
  z-index: 999;
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--d2) var(--ease), visibility var(--d2);
}
.sidebar-backdrop.visible { opacity: 1; visibility: visible; }

.main-content {
  flex: 1;
  min-inline-size: 0;
  margin-inline-start: var(--sidebar-w);
  padding-block-start: var(--header-h);
  display: flex;
  flex-direction: column;
}
.main-content.full-width { margin-inline-start: 0; }

/* Top bar — carries the brand and your position. Never repeats the page H1. */
.main-header {
  position: fixed;
  inset-block-start: 0;
  inset-inline: 0;
  z-index: 1100;
  background: var(--paper);
  border-block-end: 1px solid var(--rule);
  block-size: var(--header-h);
  display: flex;
  align-items: center;
}
.header-container {
  inline-size: 100%;
  padding-inline: var(--s4);
  display: flex;
  align-items: center;
  gap: var(--s3);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: var(--s2);
  text-decoration: none;
  color: var(--ink);
  flex-shrink: 0;
  inline-size: calc(var(--sidebar-w) - var(--s4) * 2);
}
.brand-mark { inline-size: 1.25rem; block-size: 1.25rem; border-radius: 3px; flex-shrink: 0; }
.brand-name {
  font-size: var(--t-md);
  font-weight: 700;
  letter-spacing: -0.02em;
  white-space: nowrap;
}
.brand:hover .brand-name { color: var(--accent); }

.header-sep {
  inline-size: 1px;
  block-size: 1.1rem;
  background: var(--rule);
  flex-shrink: 0;
}
.header-context {
  font-family: var(--mono);
  font-size: var(--t-xs);
  letter-spacing: 0.06em;
  color: var(--ink-muted);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  min-inline-size: 0;
}
.header-context b { color: var(--ink); font-weight: 500; }

.header-actions { margin-inline-start: auto; display: flex; align-items: center; gap: var(--s2); flex-shrink: 0; }

/* Route back to the main site. The course sat on this domain with no link
   home at all, which stranded both readers and internal link weight. */
.site-link {
  display: inline-flex;
  align-items: center;
  padding: 0.25rem var(--s3);
  min-block-size: 2rem;
  border: 1px solid var(--rule);
  border-radius: var(--r-sm);
  color: var(--ink-muted);
  font-family: var(--mono);
  font-size: var(--t-xs);
  letter-spacing: 0.04em;
  text-decoration: none;
  white-space: nowrap;
  transition: color var(--d1) var(--ease), border-color var(--d1) var(--ease);
}
.site-link:hover, .site-link:focus-visible {
  color: var(--accent);
  border-color: var(--accent);
}
/* The mobile header already carries menu, brand, search and theme controls.
   The footer link covers small screens. */
@media (max-width: 48rem) { .site-link { display: none; } }

.menu-toggle, .theme-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  inline-size: 2rem;
  block-size: 2rem;
  background: none;
  border: 1px solid transparent;
  border-radius: var(--r-sm);
  color: var(--ink-muted);
  cursor: pointer;
  flex-shrink: 0;
  transition: color var(--d1) var(--ease), background-color var(--d1) var(--ease), border-color var(--d1) var(--ease);
}
.menu-toggle:hover, .theme-toggle:hover { color: var(--ink); background: var(--panel); border-color: var(--rule); }
.menu-toggle { display: none; }
.theme-toggle .icon-sun { display: none; }
[data-theme="dark"] .theme-toggle .icon-sun { display: block; }
[data-theme="dark"] .theme-toggle .icon-moon { display: none; }
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .theme-toggle .icon-sun { display: block; }
  :root:not([data-theme="light"]) .theme-toggle .icon-moon { display: none; }
}

/* --------------------------------------------------------------------------
   6. Chapter opener
   -------------------------------------------------------------------------- */

.page-hero {
  background: var(--paper);
  border-block-end: 1px solid var(--rule);
  padding-block: var(--s7) var(--s6);
}
.hero-content { max-inline-size: var(--column); margin-inline: auto; padding-inline: var(--s6); }

.hero-eyebrow {
  display: block;
  font-family: var(--mono);
  font-size: var(--t-xs);
  font-weight: 500;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--accent);
  margin-block-end: var(--s3);
}
.hero-title {
  font-size: var(--t-disp);
  font-weight: 700;
  letter-spacing: -0.035em;
  line-height: 1.1;
  color: var(--ink);
  margin-block-end: var(--s3);
}
.hero-subtitle {
  font-size: var(--t-lg);
  color: var(--ink-muted);
  line-height: 1.6;
  margin-block-end: var(--s5);
}
.hero-actions { display: flex; gap: var(--s2); flex-wrap: wrap; align-items: center; }
.page-hero .nav-pills { margin-block-start: var(--s5); margin-block-end: 0; }

/* --------------------------------------------------------------------------
   7. Content flow
   -------------------------------------------------------------------------- */

.content-container, .container, .content-wrapper {
  inline-size: 100%;
  max-inline-size: var(--column);
  margin-inline: auto;
  padding: var(--s7) var(--s6) var(--s9);
  flex: 1;
}

/* A section, not a card. Structure comes from rules and space. */
.content-card {
  padding: 0;
  margin: 0 0 var(--s7);
  background: none;
  border: 0;
  border-radius: 0;
  box-shadow: none;
  scroll-margin-block-start: calc(var(--header-h) + var(--s4));
}
.content-card > h2 {
  margin-block-end: var(--s4);
  padding-block-end: var(--s3);
  border-block-end: 2px solid var(--ink);
  max-width: var(--measure);
}
.content-card > h3 { margin-block: var(--s6) var(--s3); }
.content-card > h4 { margin-block: var(--s5) var(--s2); }
.content-card > :first-child { margin-block-start: 0; }
.content-card > :last-child { margin-block-end: 0; }

.card {
  background: var(--panel);
  border: 1px solid var(--rule);
  border-radius: var(--r-md);
  padding: var(--s5);
  margin-block-end: var(--s5);
}
.card-header { margin-block-end: var(--s4); padding-block-end: var(--s3); border-block-end: 1px solid var(--rule); }
.card-title { font-size: var(--t-h3); margin: 0; }
.card > :last-child { margin-block-end: 0; }

h2 + p, h3 + p, h4 + p { margin-block-start: 0; }
h2 + ul, h2 + ol, h3 + ul, h3 + ol { margin-block-start: var(--s3); }

.heading-anchor {
  margin-inline-start: var(--s2);
  font-family: var(--mono);
  font-size: 0.62em;
  font-weight: 400;
  color: var(--ink-faint);
  text-decoration: none;
  opacity: 0;
  transition: opacity var(--d1) var(--ease), color var(--d1) var(--ease);
}
h2:hover > .heading-anchor, .heading-anchor:focus-visible { opacity: 1; }
.heading-anchor:hover { color: var(--accent); }

/* --------------------------------------------------------------------------
   8. Callouts — tinted ground, 1px border, mono label. No side stripes.
   -------------------------------------------------------------------------- */

.alert, .expert-tip, .tips-box, .example-box, .practical-example,
.example-case, .case-study, .results, .integration-example {
  margin-block: var(--s5);
  padding: var(--s4) var(--s5);
  border: 1px solid var(--rule);
  border-radius: var(--r-md);
  background: var(--panel);
  color: var(--ink-body);
  max-width: var(--measure);
  font-size: var(--t-md);
}
.alert > :last-child, .expert-tip > :last-child,
.tips-box > :last-child, .example-box > :last-child { margin-block-end: 0; }

.alert > strong:first-child,
.alert > p:first-child > strong:first-child {
  display: block;
  font-family: var(--mono);
  font-size: var(--t-xs);
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  margin-block-end: var(--s2);
}

.alert-info    { background: var(--info-bg);    border-color: var(--info-line); }
.alert-success { background: var(--success-bg); border-color: var(--success-line); }
.alert-warning { background: var(--warning-bg); border-color: var(--warning-line); }
.alert-danger  { background: var(--danger-bg);  border-color: var(--danger-line); }

.alert-info > strong:first-child    { color: var(--info); }
.alert-success > strong:first-child { color: var(--success); }
.alert-warning > strong:first-child { color: var(--warning); }
.alert-danger > strong:first-child  { color: var(--danger); }

.alert ul, .alert ol { margin-block-end: 0; max-width: none; }
.alert li::before { background: currentColor; opacity: 0.45; }

.expert-tip { background: var(--accent-tint); border-color: var(--accent-line); }
.expert-tip h3 {
  font-family: var(--mono);
  font-size: var(--t-xs);
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--accent);
  margin-block-end: var(--s2);
}
.tips-box { background: var(--warning-bg); border-color: var(--warning-line); }
.tips-box ol, .tips-box ul { margin-block-end: 0; max-width: none; }

.example-box, .practical-example, .example, .example-case,
.integration-example, .case-study { background: var(--sunken); }
.example-box h3, .practical-example h3, .example-case h3 {
  font-size: var(--t-h4);
  margin-block-end: var(--s2);
}
.case-before, .case-after {
  padding: var(--s3) var(--s4);
  border: 1px solid var(--rule);
  border-radius: var(--r-sm);
  background: var(--paper);
  margin-block: var(--s3);
}
.case-before { border-color: var(--danger-line); }
.case-after  { border-color: var(--success-line); }
.case-details { color: var(--ink-muted); font-size: var(--t-sm); }
.results { background: var(--success-bg); border-color: var(--success-line); }

/* --------------------------------------------------------------------------
   9. Buttons
   -------------------------------------------------------------------------- */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--s2);
  padding: 0.55rem 1.1rem;
  font-family: inherit;
  font-size: var(--t-md);
  font-weight: 600;
  line-height: 1.2;
  border: 1px solid transparent;
  border-radius: var(--r-md);
  cursor: pointer;
  text-decoration: none;
  white-space: nowrap;
  transition: background-color var(--d1) var(--ease), border-color var(--d1) var(--ease), color var(--d1) var(--ease);
}
.btn-primary { background: var(--accent); color: var(--on-accent); border-color: var(--accent); }
.btn-primary:hover { background: var(--accent-hover); border-color: var(--accent-hover); color: var(--on-accent); }

.btn-secondary, .btn-outline {
  background: var(--paper);
  color: var(--ink);
  border-color: var(--rule-strong);
}
.btn-secondary:hover, .btn-outline:hover { background: var(--panel); border-color: var(--ink-faint); color: var(--ink); }

.btn-premium { background: var(--ink); color: var(--paper); border-color: var(--ink); }
.btn-premium:hover { background: var(--ink-body); border-color: var(--ink-body); color: var(--paper); }

.btn-ghost { background: none; color: var(--ink-muted); border-color: transparent; }
.btn-ghost:hover { color: var(--ink); background: var(--panel); }

/* --------------------------------------------------------------------------
   10. Pills, badges, breadcrumb
   -------------------------------------------------------------------------- */

.nav-pills { display: flex; flex-wrap: wrap; gap: var(--s2); padding: 0; margin-block-end: var(--s5); background: none; list-style: none; }
.nav-pill {
  display: inline-flex;
  align-items: center;
  gap: var(--s2);
  padding: 0.3rem 0.7rem;
  font-size: var(--t-sm);
  font-weight: 500;
  color: var(--ink-muted);
  background: var(--paper);
  border: 1px solid var(--rule);
  border-radius: var(--r-sm);
  text-decoration: none;
  transition: color var(--d1) var(--ease), border-color var(--d1) var(--ease), background-color var(--d1) var(--ease);
}
.nav-pill:hover { color: var(--ink); border-color: var(--rule-strong); background: var(--panel); }
.nav-pill.active { color: var(--on-accent); background: var(--accent); border-color: var(--accent); font-weight: 600; }

.badge {
  display: inline-flex;
  align-items: center;
  padding: 0.1rem 0.45rem;
  font-family: var(--mono);
  font-size: var(--t-xs);
  font-weight: 500;
  border-radius: var(--r-sm);
  border: 1px solid transparent;
  white-space: nowrap;
}
.badge-primary { background: var(--accent-tint);  color: var(--accent);  border-color: var(--accent-line); }
.badge-success { background: var(--success-bg);   color: var(--success); border-color: var(--success-line); }
.badge-warning { background: var(--warning-bg);   color: var(--warning); border-color: var(--warning-line); }
.badge-danger  { background: var(--danger-bg);    color: var(--danger);  border-color: var(--danger-line); }
.badge-new     { background: var(--accent);       color: var(--on-accent); border-color: var(--accent); }

.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--s2);
  font-size: var(--t-sm);
  color: var(--ink-faint);
  margin-block-end: var(--s3);
  list-style: none;
  padding: 0;
  max-width: none;
}
.breadcrumb li { margin: 0; }
.breadcrumb li::before { content: none; }
.breadcrumb a { color: var(--ink-muted); text-decoration: none; }
.breadcrumb a:hover { color: var(--accent); text-decoration: underline; }
.breadcrumb-sep { color: var(--rule-strong); }
.breadcrumb [aria-current="page"] { color: var(--ink-muted); }

/* --------------------------------------------------------------------------
   11. Table of contents
   -------------------------------------------------------------------------- */

.toc {
  margin-block: 0 var(--s7);
  padding: var(--s4) var(--s5);
  background: var(--panel);
  border: 1px solid var(--rule);
  border-radius: var(--r-md);
  max-width: var(--measure);
}
.toc-title {
  font-family: var(--mono);
  font-size: var(--t-xs);
  font-weight: 500;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--ink-faint);
  margin-block-end: var(--s3);
}
.toc ol { list-style: none; margin: 0; padding: 0; max-width: none; counter-reset: toc; columns: 2; column-gap: var(--s6); }
.toc li { margin-block-end: var(--s2); break-inside: avoid; counter-increment: toc; }
.toc li::before { content: none; }
.toc a {
  display: flex;
  gap: var(--s2);
  align-items: baseline;
  color: var(--ink-body);
  text-decoration: none;
  font-size: var(--t-md);
  line-height: 1.45;
}
.toc a::before {
  content: counter(toc, decimal-leading-zero);
  font-family: var(--mono);
  font-size: var(--t-xs);
  color: var(--ink-faint);
  font-variant-numeric: tabular-nums;
  flex-shrink: 0;
}
.toc a:hover, .toc a:hover::before { color: var(--accent); }

/* --------------------------------------------------------------------------
   12. Grids and feature lists
   -------------------------------------------------------------------------- */

.grid { display: grid; gap: var(--s4); margin-block: var(--s5); }
.grid-2 { grid-template-columns: repeat(auto-fit, minmax(min(100%, 17rem), 1fr)); }
.grid-3 { grid-template-columns: repeat(auto-fit, minmax(min(100%, 15rem), 1fr)); }
.grid > div > :last-child { margin-block-end: 0; }
.grid > div:not([class]) {
  padding: var(--s4);
  background: var(--panel);
  border: 1px solid var(--rule);
  border-radius: var(--r-sm);
}
.grid > div:not([class]) h3, .grid > div:not([class]) h4 { font-size: var(--t-h4); margin-block-end: var(--s2); }
.grid > div:not([class]) p { color: var(--ink-muted); font-size: var(--t-md); max-width: none; }

.feature-grid, .benefits-grid, .symptoms-grid, .techniques-grid,
.best-practices-grid, .tips-grid, .industry-examples {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 17rem), 1fr));
  gap: 0 var(--s6);
  margin-block: var(--s5);
}
.feature-card, .benefit-item, .practice-item, .tip-item, .integration-item {
  padding: var(--s4) 0;
  border-block-start: 1px solid var(--rule);
  background: none;
}
.feature-card h3, .benefit-item h3, .practice-item h3, .tip-item h3,
.feature-title { font-size: var(--t-h4); margin-block-end: var(--s2); }
.feature-description, .benefit-item p, .practice-item p, .tip-item p, .feature-card p {
  color: var(--ink-muted);
  font-size: var(--t-md);
  line-height: 1.65;
  max-width: none;
  margin-block-end: 0;
}
.feature-icon, .benefit-icon, .practice-icon, .metric-icon {
  font-size: 1.2rem;
  line-height: 1;
  margin-block-end: var(--s2);
  display: block;
  filter: grayscale(0.35);
}
.practice-details { color: var(--ink-muted); font-size: var(--t-md); }
.best-practices { margin-block: var(--s5); }
.best-practices .practice-item:first-child { border-block-start: 0; padding-block-start: 0; }

.advanced-tips { margin-block: var(--s6); }
.advanced-tips > h3 {
  font-family: var(--mono);
  font-size: var(--t-xs);
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-faint);
  padding-block-end: var(--s2);
  border-block-end: 1px solid var(--rule);
  margin-block-end: var(--s2);
}

/* Definition lists — the glossary */
dl { margin-block: var(--s4); max-width: var(--measure); }
dt {
  font-weight: 600;
  color: var(--accent);
  font-size: var(--t-base);
  margin-block-start: var(--s4);
  padding-block-end: var(--s1);
}
dt:first-child { margin-block-start: 0; }
dd {
  margin: 0;
  padding-block-end: var(--s3);
  border-block-end: 1px solid var(--rule);
  color: var(--ink-muted);
  line-height: 1.7;
}
dd:last-child { border-block-end: 0; }
dt .term-ar { color: var(--ink-faint); font-weight: 400; font-size: var(--t-sm); }

/* --------------------------------------------------------------------------
   13. Metrics
   -------------------------------------------------------------------------- */

.metrics-container, .metrics-grid, .metrics-dashboard,
.stat-cards, .page-metrics, .measurement-framework {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 13rem), 1fr));
  gap: var(--s4);
  margin-block: var(--s5);
}
.metric-card, .stat-card, .roi-metric {
  padding: var(--s4);
  background: var(--panel);
  border: 1px solid var(--rule);
  border-radius: var(--r-sm);
  transition: border-color var(--d2) var(--ease);
}
.metric-card:hover, .stat-card:hover, .roi-metric:hover { border-color: var(--rule-strong); }
.metric-card h3, .metric-card h4 { font-size: var(--t-h4); margin-block-end: var(--s2); }
.metric-card p { color: var(--ink-muted); font-size: var(--t-md); max-width: none; }

.metric-number, .stat-number, .suppression-score {
  display: block;
  font-family: var(--mono);
  font-size: 1.9rem;
  font-weight: 500;
  line-height: 1.05;
  letter-spacing: -0.04em;
  color: var(--ink);
  font-variant-numeric: tabular-nums;
  background: none;
  -webkit-text-fill-color: currentColor;
  margin-block-end: var(--s1);
}
.metric-label, .stat-card p { font-size: var(--t-md); color: var(--ink-muted); margin: 0; max-width: none; }
.metric-target {
  margin-block-start: var(--s3);
  padding-block-start: var(--s3);
  border-block-start: 1px solid var(--rule);
  font-family: var(--mono);
  font-size: var(--t-xs);
  color: var(--accent);
  font-variant-numeric: tabular-nums;
}
.roi-section, .suppression-dashboard, .interactive-chart {
  padding: var(--s5);
  background: var(--panel);
  border: 1px solid var(--rule);
  border-radius: var(--r-md);
  margin-block: var(--s5);
}

/* --------------------------------------------------------------------------
   14. Timeline and steps
   -------------------------------------------------------------------------- */

.timeline { position: relative; padding-inline-start: var(--s7); margin-block: var(--s5); list-style: none; }
.timeline::before {
  content: "";
  position: absolute;
  inset-inline-start: 0.4rem;
  inset-block: 0.6rem;
  inline-size: 1px;
  background: var(--rule);
}
.timeline-item { position: relative; padding-block-end: var(--s5); margin: 0; }
.timeline-item:last-child { padding-block-end: 0; }
.timeline-item::before {
  content: "";
  position: absolute;
  inset-inline-start: calc(var(--s7) * -1 + 0.15rem);
  inset-block-start: 0.55rem;
  inline-size: 9px; block-size: 9px;
  background: var(--accent);
  box-shadow: 0 0 0 3px var(--paper);
}
.timeline-item h3, .timeline-item h4 { font-size: var(--t-h4); margin-block-end: var(--s2); }
.timeline-item p { color: var(--ink-muted); margin-block-end: 0; }

.timeline-item:has(.timeline-marker)::before { content: none; }
.timeline-marker {
  position: absolute;
  inset-inline-start: calc(var(--s7) * -1 - 0.1rem);
  inset-block-start: 0.1rem;
  inline-size: 1.5rem; block-size: 1.5rem;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--r-sm);
  background: var(--accent-tint);
  border: 1px solid var(--accent-line);
  color: var(--accent);
  font-family: var(--mono);
  font-size: var(--t-xs);
  font-weight: 500;
  font-variant-numeric: tabular-nums;
}
.timeline-content > :last-child { margin-block-end: 0; }
.timeline-content h3, .timeline-content h4 { margin-block-end: var(--s2); }

.framework-steps, .recovery-steps { margin-block: var(--s5); }
.step {
  padding: var(--s4) 0;
  border-block-start: 1px solid var(--rule);
  background: none;
  border-radius: 0;
  margin: 0;
  display: flex;
  gap: var(--s4);
  align-items: flex-start;
}
.step:last-child { border-block-end: 1px solid var(--rule); }
.step > :last-child { margin-block-end: 0; }
.step h3, .step h4 { font-size: var(--t-h4); margin-block-end: var(--s2); }
.step-number {
  flex-shrink: 0;
  inline-size: 1.6rem; block-size: 1.6rem;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--r-sm);
  background: var(--accent-tint);
  color: var(--accent);
  font-family: var(--mono);
  font-size: var(--t-xs);
  font-weight: 500;
  font-variant-numeric: tabular-nums;
}
.step-content { flex: 1; min-inline-size: 0; }
.step-content > :last-child { margin-block-end: 0; }

/* --------------------------------------------------------------------------
   15. Tools, techniques, related links
   -------------------------------------------------------------------------- */

.tools-grid, .tool-list, .monitoring-tools, .entity-links, .download-resources {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 15rem), 1fr));
  gap: var(--s3);
  margin-block: var(--s4);
}
.tool-category { margin-block: var(--s5); }
.tool-category > h3 {
  font-family: var(--mono);
  font-size: var(--t-xs);
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-faint);
  padding-block-end: var(--s2);
  border-block-end: 1px solid var(--rule);
  margin-block-end: var(--s3);
}
.tool-item {
  padding: var(--s4);
  background: var(--panel);
  border: 1px solid var(--rule);
  border-radius: var(--r-sm);
  transition: border-color var(--d2) var(--ease);
}
.tool-item:hover { border-color: var(--rule-strong); }
.tool-item strong { display: block; font-size: var(--t-base); color: var(--ink); margin-block-end: var(--s1); }
.tool-item p { font-size: var(--t-md); color: var(--ink-muted); margin-block-end: var(--s3); max-width: none; }
.tool-item a { font-size: var(--t-md); font-weight: 500; }
.tool-section { margin-block: var(--s6); }

.techniques-grid, .advanced-techniques {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 21rem), 1fr));
  gap: 0 var(--s6);
  margin-block: var(--s5);
}
.technique-link {
  display: flex;
  align-items: baseline;
  gap: var(--s3);
  padding: var(--s3) var(--s2);
  border-block-start: 1px solid var(--rule);
  color: var(--ink-body);
  text-decoration: none;
  font-size: var(--t-md);
  line-height: 1.5;
  transition: color var(--d1) var(--ease), background-color var(--d1) var(--ease);
}
.technique-link:hover { color: var(--accent); background: var(--panel); }
.technique-link span:first-child {
  font-family: var(--mono);
  font-size: var(--t-xs);
  color: var(--ink-faint);
  font-variant-numeric: tabular-nums;
  min-inline-size: 2em;
  flex-shrink: 0;
}
.technique-link:hover span:first-child { color: var(--accent); }
.technique-section, .advanced-section, .update-section, .alerts-section { margin-block: var(--s6); }

.next-nav, .related-content {
  margin-block-start: var(--s8);
  padding-block-start: var(--s5);
  border-block-start: 2px solid var(--ink);
  display: flex;
  flex-wrap: wrap;
  gap: var(--s3);
  align-items: center;
}

.semantic-bridge, .semantic-inversion, .entity-mapping, .entity-modal-content,
.traditional-context, .redirect-context, .integration-examples, .code-example { margin-block: var(--s5); }
.traditional-context, .redirect-context {
  padding: var(--s4);
  background: var(--sunken);
  border: 1px solid var(--rule);
  border-radius: var(--r-sm);
}
.major-update {
  padding: var(--s4);
  background: var(--warning-bg);
  border: 1px solid var(--warning-line);
  border-radius: var(--r-sm);
  margin-block: var(--s4);
}
.custom-list { list-style: none; padding-inline-start: 0; }
.custom-list li { padding-inline-start: var(--s5); position: relative; }
.page-url { font-family: var(--mono); font-size: var(--t-md); color: var(--ink-muted); direction: ltr; unicode-bidi: isolate; word-break: break-all; }
.video-content, .social-media, .comments, .comments-section, .advertisement { margin-block: var(--s5); }

/* --------------------------------------------------------------------------
   16. Tables
   -------------------------------------------------------------------------- */

.table-container { overflow-x: auto; margin-block: var(--s5); scrollbar-width: thin; max-width: 100%; }
table { inline-size: 100%; border-collapse: collapse; font-size: var(--t-md); background: var(--paper); }
th {
  background: var(--panel);
  color: var(--ink);
  font-weight: 600;
  text-align: start;
  padding: var(--s3) var(--s4);
  border-block-end: 2px solid var(--ink);
  white-space: nowrap;
}
td { padding: var(--s3) var(--s4); border-block-end: 1px solid var(--rule); vertical-align: top; color: var(--ink-body); }
tbody tr:hover { background: var(--panel); }

/* --------------------------------------------------------------------------
   17. Footer
   -------------------------------------------------------------------------- */

.footer {
  background: var(--panel);
  border-block-start: 1px solid var(--rule);
  padding-block: var(--s6);
  margin-block-start: auto;
}
.footer-content { max-inline-size: var(--column); margin-inline: auto; padding-inline: var(--s6); }
.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: var(--s2) var(--s5);
  margin-block-end: var(--s4);
  padding-block-end: var(--s4);
  border-block-end: 1px solid var(--rule);
}
.footer-links a { color: var(--ink-muted); font-size: var(--t-md); font-weight: 500; text-decoration: none; }
.footer-links a:hover { color: var(--accent); text-decoration: underline; }
.footer p { color: var(--ink-faint); font-size: var(--t-sm); margin: 0; max-width: none; }

/* --------------------------------------------------------------------------
   18. Reading aids
   -------------------------------------------------------------------------- */

.scroll-progress {
  position: fixed;
  inset-block-start: 0;
  inset-inline-start: 0;
  block-size: 2px;
  inline-size: 0;
  background: var(--accent);
  z-index: 9999;
  transition: inline-size 90ms linear;
}
.scroll-top {
  position: fixed;
  inset-block-end: var(--s5);
  inset-inline-end: var(--s5);
  inline-size: 2.5rem; block-size: 2.5rem;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--paper);
  color: var(--ink-muted);
  border: 1px solid var(--rule-strong);
  border-radius: var(--r-md);
  cursor: pointer;
  box-shadow: var(--shadow-float);
  opacity: 0;
  visibility: hidden;
  transform: translateY(0.4rem);
  transition: opacity var(--d2) var(--ease), transform var(--d2) var(--ease),
              visibility var(--d2), color var(--d1) var(--ease), border-color var(--d1) var(--ease);
  z-index: 800;
}
.scroll-top.visible { opacity: 1; visibility: visible; transform: translateY(0); }
.scroll-top:hover { color: var(--accent); border-color: var(--accent); }

/* --------------------------------------------------------------------------
   19. Search
   -------------------------------------------------------------------------- */

.search-trigger {
  display: inline-flex;
  align-items: center;
  gap: var(--s2);
  padding: 0.25rem var(--s3);
  min-block-size: 2rem;
  background: var(--panel);
  border: 1px solid var(--rule);
  border-radius: var(--r-sm);
  color: var(--ink-muted);
  font-family: inherit;
  font-size: var(--t-sm);
  cursor: pointer;
  transition: color var(--d1) var(--ease), border-color var(--d1) var(--ease);
}
.search-trigger:hover { color: var(--ink); border-color: var(--rule-strong); }
.search-trigger .kbd {
  font-family: var(--mono);
  font-size: var(--t-xs);
  color: var(--ink-faint);
  border: 1px solid var(--rule);
  border-radius: 3px;
  padding: 0 0.3rem;
}
@media (max-width: 48rem) { .search-trigger .search-label, .search-trigger .kbd { display: none; } }

.search-overlay {
  position: fixed;
  inset: 0;
  z-index: 1500;
  background: oklch(15% 0.002 286 / 0.45);
  display: flex;
  justify-content: center;
  align-items: flex-start;
  padding: clamp(var(--s4), 8vh, var(--s9)) var(--s4) var(--s4);
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--d2) var(--ease), visibility var(--d2);
}
.search-overlay.open { opacity: 1; visibility: visible; }
.search-panel {
  inline-size: 100%;
  max-inline-size: 42rem;
  max-block-size: 100%;
  display: flex;
  flex-direction: column;
  background: var(--paper);
  border: 1px solid var(--rule-strong);
  border-radius: var(--r-lg);
  box-shadow: var(--shadow-float);
  overflow: hidden;
  transform: translateY(-0.4rem);
  transition: transform var(--d2) var(--ease);
}
.search-overlay.open .search-panel { transform: translateY(0); }
.search-field {
  display: flex;
  align-items: center;
  gap: var(--s3);
  padding: var(--s4) var(--s5);
  border-block-end: 1px solid var(--rule);
  flex-shrink: 0;
}
.search-field svg { color: var(--ink-faint); }
.search-input {
  flex: 1;
  min-inline-size: 0;
  border: 0;
  background: none;
  font-family: inherit;
  font-size: var(--t-lg);
  color: var(--ink);
  outline: none;
}
.search-input::placeholder { color: var(--ink-faint); }
.search-results { overflow-y: auto; overscroll-behavior: contain; }
.search-results:empty { display: none; }
.search-hit {
  display: block;
  padding: var(--s3) var(--s5);
  border-block-end: 1px solid var(--rule);
  color: var(--ink-body);
  text-decoration: none;
}
.search-hit:last-child { border-block-end: 0; }
.search-hit:hover, .search-hit.is-active { background: var(--accent-tint); }
.search-hit-chapter { font-family: var(--mono); font-size: var(--t-xs); color: var(--accent); letter-spacing: 0.05em; }
.search-hit-title { display: block; font-weight: 600; color: var(--ink); margin-block: 0.1rem; }
.search-hit-context {
  font-size: var(--t-md);
  color: var(--ink-muted);
  line-height: 1.5;
  overflow: hidden;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
}
.search-hit mark { background: var(--accent-line); color: var(--ink); border-radius: 2px; padding: 0 0.1em; }
.search-empty, .search-status { padding: var(--s5); color: var(--ink-muted); font-size: var(--t-md); text-align: center; }
.search-foot {
  display: flex;
  gap: var(--s4);
  padding: var(--s2) var(--s5);
  border-block-start: 1px solid var(--rule);
  background: var(--panel);
  font-family: var(--mono);
  font-size: var(--t-xs);
  color: var(--ink-faint);
  flex-shrink: 0;
}

/* --------------------------------------------------------------------------
   20. Home — chapter index and figures
   -------------------------------------------------------------------------- */

.chapter-index { list-style: none; margin: 0; padding: 0; max-width: none; border-block-start: 1px solid var(--rule); }
.chapter-index li { margin: 0; }
.chapter-index li::before { content: none; }
.chapter-index a {
  display: grid;
  grid-template-columns: 2.75rem 1fr;
  gap: 0 var(--s4);
  align-items: baseline;
  padding: var(--s4) var(--s2);
  border-block-end: 1px solid var(--rule);
  color: var(--ink-body);
  text-decoration: none;
  transition: background-color var(--d1) var(--ease), color var(--d1) var(--ease);
}
.chapter-index a:hover { background: var(--panel); color: var(--accent); }
.ci-num {
  font-family: var(--mono);
  font-size: var(--t-sm);
  font-variant-numeric: tabular-nums;
  color: var(--ink-faint);
  transition: color var(--d1) var(--ease);
}
.chapter-index a:hover .ci-num { color: var(--accent); }
.ci-title { display: block; font-weight: 600; font-size: var(--t-base); color: var(--ink); margin-block-end: 0.1rem; transition: color var(--d1) var(--ease); }
.chapter-index a:hover .ci-title { color: var(--accent); }
.ci-desc { display: block; font-size: var(--t-md); color: var(--ink-muted); line-height: 1.55; max-inline-size: 64ch; }
.ci-tag { display: inline-block; margin-inline-start: var(--s2); font-family: var(--mono); font-size: var(--t-xs); font-weight: 500; color: var(--accent); }

.figures {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: var(--s5) var(--s7);
  margin-block: var(--s6);
  padding-block: var(--s4);
  border-block: 1px solid var(--rule);
  list-style: none;
  padding-inline: 0;
  max-width: none;
}
.figures li { margin: 0; }
.figures li::before { content: none; }
.fig-value {
  display: block;
  font-family: var(--mono);
  font-size: 1.5rem;
  font-weight: 500;
  letter-spacing: -0.03em;
  color: var(--ink);
  font-variant-numeric: tabular-nums;
  line-height: 1.1;
}
.fig-label { display: block; font-size: var(--t-md); color: var(--ink-muted); margin-block-start: 0.1rem; }
.section-label {
  font-family: var(--mono);
  font-size: var(--t-xs);
  font-weight: 500;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--ink-faint);
  margin-block-end: var(--s3);
  padding-block-end: var(--s2);
  border-block-end: 1px solid var(--rule);
}

/* --------------------------------------------------------------------------
   21. 404
   -------------------------------------------------------------------------- */

.error-container { min-block-size: 50vh; display: flex; flex-direction: column; justify-content: center; max-inline-size: 44rem; }
.error-code {
  font-family: var(--mono);
  font-size: clamp(3rem, 10vw, 5rem);
  font-weight: 500;
  line-height: 1;
  letter-spacing: -0.06em;
  color: var(--accent);
  margin-block-end: var(--s4);
  font-variant-numeric: tabular-nums;
}
.error-message { font-size: var(--t-h2); font-weight: 650; color: var(--ink); margin-block-end: var(--s3); max-inline-size: 24ch; }
.error-actions { display: flex; gap: var(--s2); flex-wrap: wrap; margin-block-start: var(--s5); }

/* --------------------------------------------------------------------------
   22. Utilities and legacy hooks
   -------------------------------------------------------------------------- */

.sr-only {
  position: absolute;
  inline-size: 1px; block-size: 1px;
  padding: 0; margin: -1px;
  overflow: hidden;
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
}
.lede { font-size: var(--t-lg); color: var(--ink-muted); line-height: 1.65; }
.mono { font-family: var(--mono); font-variant-numeric: tabular-nums; }
.eyebrow {
  font-family: var(--mono);
  font-size: var(--t-xs);
  font-weight: 500;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--ink-faint);
}

/* Inert legacy classes from the previous designs */
.glass, .glass-dark, .pattern-dots, .glow, .parallax, .hover-card, .spinner, .fab,
.gradient-text, .gradient-text-premium {
  background: none;
  backdrop-filter: none;
  -webkit-backdrop-filter: none;
  box-shadow: none;
  border: 0;
  animation: none;
  -webkit-text-fill-color: currentColor;
  color: inherit;
}
.pattern-dots, .fab, .spinner { display: none; }

/* --------------------------------------------------------------------------
   22b. Reading aids — chapter meta, TOC scrollspy, pagination
   -------------------------------------------------------------------------- */

/* Chapter meta strip under the hero title */
.hero-meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--s2) var(--s4);
  margin-block-end: var(--s5);
  font-family: var(--mono);
  font-size: var(--t-xs);
  color: var(--ink-faint);
  list-style: none;
  padding: 0;
  max-width: none;
}
.hero-meta li { margin: 0; display: inline-flex; align-items: center; gap: var(--s2); }
.hero-meta li::before { content: none; }
.hero-meta li + li::before {
  content: "";
  display: inline-block;
  inline-size: 3px; block-size: 3px;
  background: var(--rule-strong);
  margin-inline-end: var(--s2);
}

/* TOC scrollspy — marks the section you are actually reading */
.toc a[aria-current="true"] {
  color: var(--accent);
  font-weight: 600;
}
.toc a[aria-current="true"]::before { color: var(--accent); }

/* Paired chapter pagination */
.pager {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 15rem), 1fr));
  gap: var(--s3);
  margin-block-start: var(--s8);
  padding-block-start: var(--s5);
  border-block-start: 2px solid var(--ink);
}
.pager-link {
  display: flex;
  flex-direction: column;
  gap: 0.15rem;
  padding: var(--s4);
  border: 1px solid var(--rule);
  border-radius: var(--r-md);
  text-decoration: none;
  background: var(--paper);
  transition: border-color var(--d1) var(--ease), background-color var(--d1) var(--ease);
}
.pager-link:hover { border-color: var(--accent); background: var(--panel); }
.pager-dir {
  font-family: var(--mono);
  font-size: var(--t-xs);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-faint);
}
.pager-title { font-size: var(--t-md); font-weight: 600; color: var(--ink); line-height: 1.4; }
.pager-link:hover .pager-title { color: var(--accent); }
.pager-next { text-align: start; }
.pager-prev { text-align: end; }
.pager-prev .pager-dir { justify-self: end; }

/* Rendering cost of long chapters: skip layout for sections still off-screen.
   contain-intrinsic-size keeps the scrollbar honest. */
.content-card { content-visibility: auto; contain-intrinsic-size: auto 600px; }

/* Cross-page navigation, where the browser supports it */
@view-transition { navigation: auto; }
@media (prefers-reduced-motion: reduce) {
  @view-transition { navigation: none; }
}

/* "See also" lists — link plus the reason it is worth following */
.related-list { list-style: none; margin: 0; padding: 0; max-width: var(--measure); }
.related-list li {
  padding-block: var(--s3);
  border-block-start: 1px solid var(--rule);
  font-size: var(--t-md);
  color: var(--ink-muted);
  line-height: 1.6;
}
.related-list li::before { content: none; }
.related-list li:last-child { border-block-end: 1px solid var(--rule); }
.related-list a { font-weight: 600; text-decoration: none; }
.related-list a:hover { text-decoration: underline; }

/* --------------------------------------------------------------------------
   23. Responsive
   -------------------------------------------------------------------------- */

@media (max-width: 68.75rem) {
  .sidebar { transform: translateX(100%); box-shadow: var(--shadow-drawer); inline-size: min(19rem, 86vw); }
  .sidebar.open { transform: translateX(0); }
  .main-content { margin-inline-start: 0; }
  .menu-toggle { display: inline-flex; }
  .brand { inline-size: auto; }
}

@media (max-width: 34rem) {
  .header-sep, .header-context { display: none; }
}

@media (max-width: 48rem) {
  :root { --t-base: 1rem; --header-h: 3rem; --measure: 100%; }
  .header-container, .hero-content,
  .content-container, .container, .content-wrapper,
  .footer-content { padding-inline: var(--s4); }
  .content-container, .container, .content-wrapper { padding-block: var(--s5) var(--s8); }
  .page-hero { padding-block: var(--s5); }
  .hero-title { max-inline-size: none; }
  .content-card { margin-block-end: var(--s6); }
  .card, .alert, .expert-tip, .tips-box, .example-box { padding: var(--s4); }
  .toc ol { columns: 1; }
  .chapter-index a { grid-template-columns: 2.25rem 1fr; gap: 0 var(--s3); padding-inline: 0; }
  .figures { gap: var(--s4) var(--s5); }
  .fig-value { font-size: 1.3rem; }
  .feature-grid, .benefits-grid, .metrics-container, .metrics-grid,
  .techniques-grid, .tools-grid, .tool-list { gap: 0; }
  .btn, .nav-pill, .sidebar-nav a { min-block-size: 2.75rem; }
  .btn { padding-inline: var(--s5); }
  .timeline { padding-inline-start: var(--s6); }
  .timeline-item::before { inset-inline-start: calc(var(--s6) * -1 + 0.15rem); }
  .timeline-marker { inset-inline-start: calc(var(--s6) * -1 - 0.1rem); }
  .step { flex-direction: column; gap: var(--s2); }
  .scroll-top { inset-block-end: var(--s4); inset-inline-end: var(--s4); }
}

@media (max-width: 30rem) {
  .hero-actions .btn, .error-actions .btn { inline-size: 100%; }
  th, td { padding: var(--s2) var(--s3); }
}

/* --------------------------------------------------------------------------
   24. Motion preference and print
   -------------------------------------------------------------------------- */

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}

@media print {
  .sidebar, .sidebar-backdrop, .menu-toggle, .theme-toggle, .header-actions,
  .scroll-top, .scroll-progress, .skip-link, .code-copy, .next-nav, .nav-pills,
  .search-trigger, .search-overlay, .toc {
    display: none !important;
  }
  .main-content { margin-inline-start: 0 !important; }
  .main-header { position: static; border: 0; }
  body { background: #fff; color: #000; font-size: 11pt; }
  .page-hero { padding-block: 0 1rem; border-block-end: 1pt solid #999; }
  .content-card { break-inside: avoid; }
  .content-card > h2 { border-block-end: 1pt solid #000; }
  pre, .code-block { background: #f4f4f4; color: #000; border: 1pt solid #ccc; }
  a { color: #000; text-decoration: underline; }
  a[href^="http"]::after { content: " (" attr(href) ")"; font-size: 9pt; color: #555; }
}