/* ===== DESIGN TOKENS ===== */
:root {
  /* Type scale */
  --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, 3.5rem);
  --text-3xl: clamp(2.5rem, 1rem + 4vw, 5rem);
  --text-hero: clamp(2.75rem, 0.8rem + 6vw, 6.5rem);

  /* Spacing (4px base) */
  --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 */
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  --radius-full: 9999px;

  /* Transitions */
  --transition-interactive: 180ms cubic-bezier(0.16, 1, 0.3, 1);
  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
  --ease-in: cubic-bezier(0.4, 0, 1, 1);
  --ease-in-out: cubic-bezier(0.4, 0, 0.2, 1);

  /* Content widths */
  --content-narrow: 640px;
  --content-default: 980px;
  --content-wide: 1240px;
  --content-full: 100%;

  /* Fonts */
  --font-display: 'Cabinet Grotesk', 'General Sans', 'Helvetica Neue', sans-serif;
  --font-body: 'Satoshi', 'Inter', 'Helvetica Neue', sans-serif;
  --font-mono: 'JetBrains Mono', 'Courier New', monospace;
}

/* ===== COLOR SYSTEM — "Signal" tech palette =====
   Concept: a dark, precise control-room aesthetic for a curated toolkit of AI tools.
   Cool graphite surfaces, a single cyan-electric accent used only for signal/CTA moments,
   warm amber reserved for callouts. No purple/blue-violet gradients. */

:root,
[data-theme='light'] {
  --color-bg: #f4f5f4;
  --color-surface: #ffffff;
  --color-surface-2: #fbfbfa;
  --color-surface-offset: #ececea;
  --color-surface-offset-2: #e2e1dd;
  --color-surface-dynamic: #d9d8d3;
  --color-divider: #dedcd7;
  --color-border: #d1cfc9;

  --color-text: #14181a;
  --color-text-muted: #55605f;
  --color-text-faint: #9aa19d;
  --color-text-inverse: #f4f5f4;

  --color-primary: #0a7a72;
  --color-primary-hover: #075c56;
  --color-primary-active: #054742;
  --color-primary-highlight: #cfe6e2;

  --color-accent: #ff6a3d;
  --color-accent-highlight: #ffe1d3;

  --color-error: #a4243b;
  --color-success: #3c7a4e;

  --shadow-sm: 0 1px 2px oklch(0.2 0.02 190 / 0.08);
  --shadow-md: 0 8px 20px oklch(0.2 0.02 190 / 0.1);
  --shadow-lg: 0 20px 48px oklch(0.2 0.02 190 / 0.16);
}

[data-theme='dark'] {
  --color-bg: #0c1012;
  --color-surface: #101517;
  --color-surface-2: #141a1c;
  --color-surface-offset: #171e20;
  --color-surface-offset-2: #1c2427;
  --color-surface-dynamic: #232c2f;
  --color-divider: #1e2528;
  --color-border: #2a3336;

  --color-text: #e9ecec;
  --color-text-muted: #8d9a99;
  --color-text-faint: #5b6767;
  --color-text-inverse: #101517;

  --color-primary: #3fd6c4;
  --color-primary-hover: #6ce4d6;
  --color-primary-active: #22a998;
  --color-primary-highlight: #17302d;

  --color-accent: #ff8a5c;
  --color-accent-highlight: #33241c;

  --color-error: #e07a8c;
  --color-success: #7fcb92;

  --shadow-sm: 0 1px 2px oklch(0 0 0 / 0.3);
  --shadow-md: 0 8px 24px oklch(0 0 0 / 0.4);
  --shadow-lg: 0 24px 56px oklch(0 0 0 / 0.55);
}

/* ===== LAYOUT PRIMITIVES ===== */
.container {
  max-width: var(--content-wide);
  margin-inline: auto;
  padding-inline: var(--space-5);
}
.container--default {
  max-width: var(--content-default);
}

section {
  padding-block: clamp(var(--space-16), 9vw, var(--space-32));
}

/* ===== HEADER ===== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: oklch(from var(--color-surface) l c h / 0.92);
  backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--color-divider);
}
.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-block: var(--space-4);
}
.brand {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  color: var(--color-text);
  text-decoration: none;
}
.brand-logo {
  height: 44px;
  width: auto;
  object-fit: contain;
}
[data-theme='dark'] .brand-logo {
  filter: invert(1) brightness(1.1);
}
.header-meta {
  display: flex;
  align-items: center;
  gap: var(--space-5);
}
.header-count {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  letter-spacing: 0.03em;
}
.theme-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: var(--radius-full);
  color: var(--color-text-muted);
}
.theme-toggle:hover {
  color: var(--color-text);
  background: var(--color-surface-offset);
}

/* ===== HERO ===== */
.hero {
  padding-block: clamp(var(--space-20), 12vw, var(--space-32)) clamp(var(--space-16), 8vw, var(--space-24));
  position: relative;
  overflow: clip;
}
.hero-kicker {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  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-6);
}
.hero-kicker::before {
  content: '';
  width: 6px;
  height: 6px;
  border-radius: var(--radius-full);
  background: var(--color-primary);
}
.hero h1 {
  font-family: var(--font-display);
  font-size: var(--text-hero);
  font-weight: 650;
  letter-spacing: -0.03em;
  max-width: 18ch;
  color: var(--color-text);
}
.hero h1 em {
  font-style: normal;
  color: var(--color-primary);
}
.hero-sub {
  margin-top: var(--space-6);
  font-size: var(--text-lg);
  color: var(--color-text-muted);
  max-width: 56ch;
}
.hero-stats {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-8);
  margin-top: var(--space-12);
  padding-top: var(--space-8);
  border-top: 1px solid var(--color-divider);
}
.hero-stat-value {
  font-family: var(--font-display);
  font-size: var(--text-xl);
  font-weight: 600;
  color: var(--color-text);
}
.hero-stat-label {
  font-size: var(--text-xs);
  color: var(--color-text-faint);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-top: var(--space-1);
}

/* ===== TOC / NAV PILLS ===== */
.toc {
  padding-block: var(--space-6);
  border-block: 1px solid var(--color-divider);
  position: sticky;
  top: 65px;
  z-index: 90;
  background: oklch(from var(--color-bg) l c h / 0.9);
  backdrop-filter: blur(10px);
}
.toc::after {
  content: '';
  position: absolute;
  top: 0;
  right: 0;
  bottom: 0;
  width: 32px;
  background: linear-gradient(to right, transparent, var(--color-bg));
  pointer-events: none;
}
.toc-scroll {
  display: flex;
  gap: var(--space-2);
  overflow-x: auto;
  scrollbar-width: none;
  padding-bottom: var(--space-1);
}
.toc-scroll::-webkit-scrollbar {
  display: none;
}
.toc-pill {
  flex: none;
  font-family: var(--font-body);
  font-size: var(--text-xs);
  font-weight: 500;
  color: var(--color-text-muted);
  background: var(--color-surface-offset);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-full);
  padding: var(--space-2) var(--space-4);
  text-decoration: none;
  white-space: nowrap;
}
.toc-pill:hover {
  color: var(--color-text);
  border-color: var(--color-primary);
  background: var(--color-primary-highlight);
}

/* ===== GROUP SECTIONS ===== */
.group {
  border-top: 1px solid var(--color-divider);
  scroll-margin-top: 140px;
}
.group:nth-of-type(even) {
  background: var(--color-surface);
}
.group-head {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: var(--space-6);
  align-items: baseline;
  margin-bottom: clamp(var(--space-10), 5vw, var(--space-16));
}
.group-index {
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  color: var(--color-text-faint);
}
.group-title {
  font-family: var(--font-display);
  font-size: var(--text-2xl);
  font-weight: 600;
  letter-spacing: -0.02em;
  color: var(--color-text);
}
.group-desc {
  grid-column: 2;
  color: var(--color-text-muted);
  font-size: var(--text-base);
  max-width: 62ch;
  margin-top: calc(-1 * var(--space-6) + var(--space-2));
}

/* ===== TOOL CARDS ===== */
.tool-grid {
  display: grid;
  gap: var(--space-6);
}
.tool-grid--2 {
  grid-template-columns: repeat(2, 1fr);
}
.tool-card {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1.15fr);
  gap: 0;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  overflow: clip;
  opacity: 1;
}
.tool-card:nth-of-type(even) {
  grid-template-columns: minmax(0, 1.15fr) minmax(0, 1fr);
}
.tool-card:nth-of-type(even) .tool-shot {
  order: -1;
}

@supports (animation-timeline: view()) {
  .tool-card {
    opacity: 0;
    animation: reveal-fade linear both;
    animation-timeline: view();
    animation-range: entry 0% entry 55%;
  }
}
@keyframes reveal-fade {
  to {
    opacity: 1;
  }
}

.tool-shot {
  position: relative;
  background: var(--color-surface-offset);
  min-height: 240px;
  overflow: hidden;
}
.tool-shot img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: top;
}
.tool-body {
  padding: clamp(var(--space-6), 4vw, var(--space-10));
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: var(--space-3);
}
.tool-name {
  font-family: var(--font-display);
  font-size: var(--text-xl);
  font-weight: 600;
  letter-spacing: -0.01em;
  color: var(--color-text);
}
.tool-subtitle {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.02em;
  color: var(--color-primary);
  text-transform: uppercase;
}
.tool-desc {
  font-size: var(--text-base);
  color: var(--color-text-muted);
  line-height: 1.6;
}
.tool-link {
  margin-top: var(--space-2);
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-text);
  text-decoration: none;
  width: fit-content;
  border-bottom: 1px solid var(--color-border);
  padding-bottom: 2px;
}
.tool-link:hover {
  color: var(--color-primary);
  border-color: var(--color-primary);
}
.tool-link svg {
  width: 14px;
  height: 14px;
  transition: transform var(--transition-interactive);
}
.tool-link:hover svg {
  transform: translate(2px, -2px);
}

/* ===== FOOTER ===== */
.site-footer {
  border-top: 1px solid var(--color-divider);
  padding-block: var(--space-16);
}
.footer-grid {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: flex-start;
  gap: var(--space-8);
}
.footer-note {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  max-width: 46ch;
}
.footer-sources {
  font-size: var(--text-xs);
  color: var(--color-text-faint);
}
.back-to-top {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  text-decoration: none;
}
.back-to-top:hover {
  color: var(--color-primary);
}

/* ===== RESPONSIVE ===== */
@media (max-width: 860px) {
  .tool-card,
  .tool-card:nth-of-type(even) {
    grid-template-columns: 1fr;
  }
  .tool-card:nth-of-type(even) .tool-shot {
    order: 0;
  }
  .tool-shot {
    min-height: 180px;
  }
  .group-head {
    grid-template-columns: 1fr;
    gap: var(--space-2);
  }
  .group-desc {
    grid-column: 1;
    margin-top: 0;
  }
  .hero-stats {
    gap: var(--space-6);
  }
}

@media (max-width: 640px) {
  section {
    padding-block: var(--space-12);
  }
  .toc {
    top: 61px;
  }
  .header-count {
    display: none;
  }
}