/* ===== base.css ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html {
  -moz-text-size-adjust: none;
  -webkit-text-size-adjust: none;
  text-size-adjust: none;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
  scroll-behavior: smooth;
  hanging-punctuation: first last;
  scroll-padding-top: var(--space-16);
}
body {
  min-height: 100dvh;
  line-height: 1.6;
  font-family: var(--font-body, sans-serif);
  font-size: var(--text-base);
  color: var(--color-text);
  background-color: var(--color-bg);
}
img, picture, video, canvas, svg { display: block; max-width: 100%; height: auto; }
ul[role='list'], ol[role='list'] { list-style: none; }
input, button, textarea, select { font: inherit; color: inherit; }
h1, h2, h3, h4, h5, h6 { text-wrap: balance; line-height: 1.15; }
p, li, figcaption { text-wrap: pretty; }
::selection { background: oklch(from var(--color-primary) l c h / 0.25); color: var(--color-text); }
:focus-visible { outline: 2px solid var(--color-primary); outline-offset: 3px; border-radius: var(--radius-sm); }
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}
button { cursor: pointer; background: none; border: none; }
table { border-collapse: collapse; width: 100%; }
a, button, [role='button'], [role='link'], input, textarea, select {
  transition: color var(--transition-interactive), background var(--transition-interactive),
    border-color var(--transition-interactive), box-shadow var(--transition-interactive);
}
.sr-only {
  position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px;
  overflow: hidden; clip: rect(0,0,0,0); white-space: nowrap; border-width: 0;
}

/* ===== design tokens ===== */
:root {
  --text-xs: clamp(0.75rem, 0.7rem + 0.25vw, 0.875rem);
  --text-sm: clamp(0.875rem, 0.8rem + 0.35vw, 1rem);
  --text-base: clamp(1rem, 0.95rem + 0.25vw, 1.125rem);
  --text-lg: clamp(1.125rem, 1rem + 0.75vw, 1.5rem);
  --text-xl: clamp(1.5rem, 1.2rem + 1.25vw, 2.25rem);
  --text-2xl: clamp(2rem, 1.2rem + 2.5vw, 3.25rem);
  --text-hero: clamp(2.75rem, 1rem + 5.5vw, 5.5rem);

  --space-1: 0.25rem; --space-2: 0.5rem; --space-3: 0.75rem; --space-4: 1rem;
  --space-5: 1.25rem; --space-6: 1.5rem; --space-8: 2rem; --space-10: 2.5rem;
  --space-12: 3rem; --space-16: 4rem; --space-20: 5rem; --space-24: 6rem; --space-32: 8rem;

  --radius-sm: 0.375rem; --radius-md: 0.5rem; --radius-lg: 0.75rem; --radius-xl: 1rem; --radius-full: 9999px;
  --transition-interactive: 180ms cubic-bezier(0.16, 1, 0.3, 1);

  --content-narrow: 640px; --content-default: 900px; --content-wide: 1200px;

  --font-display: 'Cabinet Grotesk', 'General Sans', sans-serif;
  --font-body: 'Satoshi', 'Inter', sans-serif;
  --font-mono: 'JetBrains Mono', ui-monospace, monospace;
}

:root, [data-theme='light'] {
  --color-bg: #f4f7f8;
  --color-surface: #ffffff;
  --color-surface-2: #fbfcfd;
  --color-surface-offset: #eaeff1;
  --color-divider: #e1e7ea;
  --color-border: #d3dbdf;
  --color-text: #10171b;
  --color-text-muted: #5a6870;
  --color-text-faint: #99a5ab;
  --color-text-inverse: #f4f7f8;
  --color-primary: #0891a6;
  --color-primary-hover: #076e80;
  --color-primary-active: #054f5c;
  --color-primary-highlight: #d3ecf0;
  --shadow-sm: 0 1px 2px oklch(0.2 0.02 220 / 0.06);
  --shadow-md: 0 4px 16px oklch(0.2 0.02 220 / 0.09);
  --shadow-lg: 0 16px 40px oklch(0.2 0.02 220 / 0.14);
}

[data-theme='dark'] {
  --color-bg: #0a0e11;
  --color-surface: #10161a;
  --color-surface-2: #141b1f;
  --color-surface-offset: #182025;
  --color-divider: #1c252a;
  --color-border: #232d33;
  --color-text: #dee6e9;
  --color-text-muted: #8a99a1;
  --color-text-faint: #556169;
  --color-text-inverse: #0a0e11;
  --color-primary: #2dd4e0;
  --color-primary-hover: #67e3ec;
  --color-primary-active: #a7edf2;
  --color-primary-highlight: #142c31;
  --shadow-sm: 0 1px 2px oklch(0 0 0 / 0.3);
  --shadow-md: 0 4px 16px oklch(0 0 0 / 0.4);
  --shadow-lg: 0 16px 40px oklch(0 0 0 / 0.55);
}

/* ===== layout ===== */
.wrap { max-width: var(--content-wide); margin-inline: auto; padding-inline: var(--space-6); }
.wrap--narrow { max-width: var(--content-default); }

.site-header {
  position: sticky; top: 0; z-index: 50;
  background: color-mix(in oklab, var(--color-bg) 88%, transparent);
  backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--color-divider);
}
.site-header__inner {
  display: flex; align-items: center; justify-content: space-between;
  padding-block: var(--space-4);
}
.brand { display: flex; align-items: center; gap: var(--space-3); text-decoration: none; color: var(--color-text); }
.brand__mark { width: 32px; height: 32px; color: var(--color-primary); flex-shrink: 0; }
.brand__text { display: flex; flex-direction: column; line-height: 1.1; }
.brand__name { font-family: var(--font-display); font-weight: 600; font-size: var(--text-base); letter-spacing: -0.01em; }
.brand__tag { font-size: var(--text-xs); color: var(--color-text-muted); }

.header-actions { display: flex; align-items: center; gap: var(--space-3); }
.icon-btn {
  display: inline-flex; align-items: center; justify-content: center;
  width: 38px; height: 38px; border-radius: var(--radius-full);
  border: 1px solid var(--color-border); color: var(--color-text-muted);
  background: var(--color-surface);
}
.icon-btn:hover { color: var(--color-primary); border-color: var(--color-primary); }
.icon-btn svg { width: 18px; height: 18px; }

.home-link {
  font-size: var(--text-sm); color: var(--color-text-muted); text-decoration: none;
  display: inline-flex; align-items: center; gap: var(--space-2);
}
.home-link:hover { color: var(--color-primary); }

.nav-link {
  font-size: var(--text-sm); color: var(--color-text-muted); text-decoration: none;
  display: inline-flex; align-items: center; gap: var(--space-2);
  padding: var(--space-2) var(--space-3); border-radius: var(--radius-full);
}
.nav-link svg { width: 16px; height: 16px; }
.nav-link:hover, .nav-link.is-active { color: var(--color-primary); background: var(--color-primary-highlight); }

/* ===== hero ===== */
.hero { padding-block: clamp(var(--space-12), 8vw, var(--space-24)); }
.hero__eyebrow {
  font-family: var(--font-mono); font-size: var(--text-xs); letter-spacing: 0.08em; text-transform: uppercase;
  color: var(--color-primary); margin-bottom: var(--space-4); display: block;
}
.hero__title {
  font-family: var(--font-display); font-weight: 600; letter-spacing: -0.02em;
  font-size: clamp(1.5rem, 1.05rem + 1.5vw, 2.3rem); max-width: 100%;
  white-space: nowrap; margin-bottom: var(--space-5);
}
@media (max-width: 900px) {
  .hero__title { white-space: normal; font-size: clamp(1.5rem, 1.1rem + 2.2vw, 2rem); }
}
.hero__lede { font-size: var(--text-lg); color: var(--color-text-muted); max-width: 62ch; margin-bottom: var(--space-8); }
.hero__stats { display: flex; gap: var(--space-8); flex-wrap: wrap; }
.stat__num { font-family: var(--font-display); font-size: var(--text-xl); font-weight: 600; color: var(--color-text); }
.stat__label { font-size: var(--text-xs); color: var(--color-text-muted); text-transform: uppercase; letter-spacing: 0.06em; }

.hero-cta {
  display: inline-flex; align-items: center; gap: var(--space-4);
  margin-top: var(--space-8); padding: var(--space-5) var(--space-6);
  background: var(--color-surface); border: 1px solid var(--color-border); border-radius: var(--radius-lg);
  text-decoration: none; color: var(--color-text); box-shadow: var(--shadow-sm); max-width: 100%;
}
.hero-cta:hover { border-color: var(--color-primary); box-shadow: var(--shadow-md); transform: translateY(-2px); }
.hero-cta__icon {
  display: inline-flex; align-items: center; justify-content: center;
  width: 18px; height: 18px; margin-right: var(--space-2); color: var(--color-primary);
  vertical-align: -3px;
}
.hero-cta__icon svg { width: 16px; height: 16px; }
.hero-cta__text { display: flex; flex-direction: column; gap: 2px; }
.hero-cta__text strong { font-family: var(--font-display); font-weight: 600; font-size: var(--text-base); display: flex; align-items: center; }
.hero-cta__text span { font-size: var(--text-sm); color: var(--color-text-muted); }
.hero-cta__arrow { margin-left: var(--space-4); color: var(--color-primary); font-size: var(--text-lg); flex-shrink: 0; }
@media (max-width: 620px) { .hero-cta { flex-wrap: wrap; } .hero-cta__arrow { display: none; } }

/* ===== search ===== */
.search-section { padding-bottom: clamp(var(--space-10), 6vw, var(--space-16)); }
.search-box {
  position: relative; display: flex; align-items: center;
  background: var(--color-surface); border: 1.5px solid var(--color-border);
  border-radius: var(--radius-lg); padding-inline: var(--space-5); box-shadow: var(--shadow-sm);
}
.search-box:focus-within { border-color: var(--color-primary); box-shadow: 0 0 0 3px var(--color-primary-highlight); }
.search-box svg { width: 20px; height: 20px; color: var(--color-text-faint); flex-shrink: 0; }
.search-box input {
  flex: 1; border: none; background: none; outline: none;
  padding-block: var(--space-4); padding-inline: var(--space-3);
  font-size: var(--text-base); color: var(--color-text);
}
.search-box input::placeholder { color: var(--color-text-faint); }
.search-clear {
  font-size: var(--text-xs); color: var(--color-text-muted); border: 1px solid var(--color-border);
  border-radius: var(--radius-full); padding: var(--space-1) var(--space-3); display: none;
}
.search-clear.is-visible { display: inline-flex; }
.search-clear:hover { color: var(--color-primary); border-color: var(--color-primary); }
.search-meta { font-size: var(--text-xs); color: var(--color-text-muted); margin-top: var(--space-3); font-family: var(--font-mono); }

#search-results { display: none; margin-top: var(--space-6); flex-direction: column; gap: var(--space-4); }
#search-results.is-active { display: flex; }
#topics-toc.is-hidden { display: none; }

/* ===== topic grid ===== */
.section-heading {
  font-family: var(--font-display); font-size: var(--text-xl); font-weight: 600;
  letter-spacing: -0.01em; margin-bottom: var(--space-6);
}
.topic-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: var(--space-5); padding-bottom: var(--space-24); }
@media (max-width: 1100px) { .topic-grid { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 620px) { .topic-grid { grid-template-columns: 1fr; } }

.topic-card {
  display: flex; flex-direction: column; gap: var(--space-3);
  background: var(--color-surface); border: 1px solid var(--color-border); border-radius: var(--radius-lg);
  padding: var(--space-6); text-decoration: none; color: var(--color-text);
  box-shadow: var(--shadow-sm);
}
.topic-card:hover { border-color: var(--color-primary); box-shadow: var(--shadow-md); transform: translateY(-2px); }
.topic-card__top { display: flex; align-items: flex-start; justify-content: space-between; gap: var(--space-3); }
.topic-card__title { font-family: var(--font-display); font-weight: 600; font-size: var(--text-lg); letter-spacing: -0.01em; }
.topic-card__count {
  font-family: var(--font-mono); font-size: var(--text-xs); color: var(--color-primary);
  background: var(--color-primary-highlight); border-radius: var(--radius-full); padding: var(--space-1) var(--space-3);
  white-space: nowrap;
}
.topic-card__preview { font-size: var(--text-sm); color: var(--color-text-muted); }
.topic-card__arrow { margin-top: auto; font-size: var(--text-sm); color: var(--color-primary); font-family: var(--font-mono); }

/* ===== link cards (topic pages + search results) ===== */
.link-list { display: flex; flex-direction: column; gap: var(--space-4); padding-bottom: var(--space-24); }
.link-card {
  background: var(--color-surface); border: 1px solid var(--color-border); border-radius: var(--radius-lg);
  padding: var(--space-6);
}
.link-card__head { display: flex; align-items: center; gap: var(--space-3); flex-wrap: wrap; margin-bottom: var(--space-2); }
.link-card__date {
  font-family: var(--font-mono); font-size: var(--text-xs); color: var(--color-text-muted);
  border: 1px solid var(--color-border); border-radius: var(--radius-full); padding: var(--space-1) var(--space-3);
}
.link-card__topic {
  font-family: var(--font-mono); font-size: var(--text-xs); color: var(--color-primary);
  background: var(--color-primary-highlight); border-radius: var(--radius-full); padding: var(--space-1) var(--space-3);
  text-decoration: none;
}
.link-card__domain { font-size: var(--text-xs); color: var(--color-text-faint); }
.link-card__format {
  display: inline-flex; align-items: center; gap: var(--space-1);
  font-family: var(--font-mono); font-size: var(--text-xs); color: var(--color-text-muted);
  background: var(--color-surface-offset); border-radius: var(--radius-full); padding: var(--space-1) var(--space-3);
}
.link-card__format svg { width: 12px; height: 12px; }
.link-card__title { font-family: var(--font-display); font-weight: 600; font-size: var(--text-lg); margin-bottom: var(--space-2); }
.link-card__title a { color: var(--color-text); text-decoration: none; }
.link-card__title a:hover { color: var(--color-primary); }
.link-card__summary { color: var(--color-text-muted); font-size: var(--text-base); margin-bottom: var(--space-3); max-width: 72ch; }
.link-card__original {
  display: inline-flex; align-items: center; gap: var(--space-2);
  font-size: var(--text-sm); color: var(--color-primary); text-decoration: none; font-weight: 500;
}
.link-card__original svg { width: 14px; height: 14px; }
.link-card__original:hover { color: var(--color-primary-hover); }
mark { background: var(--color-primary-highlight); color: var(--color-text); border-radius: 3px; padding: 0 2px; }

/* ===== topic page header ===== */
.topic-header { padding-block: clamp(var(--space-10), 6vw, var(--space-16)); }
.topic-header__title { font-family: var(--font-display); font-weight: 600; font-size: var(--text-2xl); letter-spacing: -0.02em; margin-bottom: var(--space-3); }
.topic-header__count { font-size: var(--text-base); color: var(--color-text-muted); font-family: var(--font-mono); }

.empty-state { text-align: center; padding-block: var(--space-16); color: var(--color-text-muted); }

/* ===== newsletter ===== */
.range-controls-wrap { padding-bottom: var(--space-8); }
.range-controls {
  display: flex; flex-direction: column; gap: var(--space-5);
  background: var(--color-surface); border: 1px solid var(--color-border); border-radius: var(--radius-lg);
  padding: var(--space-6); box-shadow: var(--shadow-sm);
}
.preset-row { display: flex; gap: var(--space-2); flex-wrap: wrap; }
.preset-btn {
  font-size: var(--text-sm); color: var(--color-text-muted);
  border: 1px solid var(--color-border); border-radius: var(--radius-full);
  padding: var(--space-2) var(--space-4); background: var(--color-surface-2);
}
.preset-btn:hover { border-color: var(--color-primary); color: var(--color-primary); }
.preset-btn.is-active { border-color: var(--color-primary); color: var(--color-primary); background: var(--color-primary-highlight); font-weight: 500; }
.custom-range { display: flex; align-items: center; gap: var(--space-4); flex-wrap: wrap; }
.custom-range__label { font-size: var(--text-sm); color: var(--color-text-muted); white-space: nowrap; }
.custom-range input[type='range'] { flex: 1; min-width: 160px; accent-color: var(--color-primary); }
.custom-range__value {
  font-family: var(--font-mono); font-size: var(--text-sm); color: var(--color-text);
  white-space: nowrap; min-width: 84px; text-align: right;
}

.newsletter-topic-section { margin-bottom: var(--space-10); }
.newsletter-topic-section:last-child { margin-bottom: var(--space-24); }
.newsletter-topic-section__heading { display: flex; align-items: center; gap: var(--space-3); margin-bottom: var(--space-4); }
.newsletter-topic-section__heading h2 { font-family: var(--font-display); font-size: var(--text-lg); font-weight: 600; letter-spacing: -0.01em; }
.newsletter-topic-section__count {
  font-family: var(--font-mono); font-size: var(--text-xs); color: var(--color-primary);
  background: var(--color-primary-highlight); border-radius: var(--radius-full); padding: var(--space-1) var(--space-3);
}

.site-footer {
  border-top: 1px solid var(--color-divider); padding-block: var(--space-10);
  font-size: var(--text-xs); color: var(--color-text-faint); font-family: var(--font-mono);
}
.site-footer a { color: var(--color-text-muted); }