/* ============================================================
   Theme Variables
   - Light theme (default): 浅蓝白净风格，对应优启通主站
   - Dark theme: 深邃蓝紫渐变
   ============================================================ */

:root,
:root[data-theme="light"] {
  --bg: #f5f9ff;
  --bg-2: #ffffff;
  --bg-3: #eef4ff;
  --card: #ffffff;
  --card-2: #f7faff;
  --line: #e3ebf7;
  --line-soft: #eef2fa;

  --text: #0f2749;
  --text-dim: #4a5a78;
  --muted: #8a97ae;

  --brand: #2b7cff;
  --brand-2: #0ea5e9;
  --accent: #00b894;

  --grad: linear-gradient(135deg, #2b7cff 0%, #4facfe 50%, #6ec6ff 100%);
  --grad-soft: linear-gradient(135deg, rgba(43, 124, 255, 0.1), rgba(14, 165, 233, 0.08));

  --pill-bg: rgba(43, 124, 255, 0.08);
  --pill-text: #1f5fd6;
  --pill-border: rgba(43, 124, 255, 0.22);

  --tile-bg: linear-gradient(135deg, rgba(43, 124, 255, 0.1), rgba(110, 198, 255, 0.08));
  --tile-border: rgba(43, 124, 255, 0.2);
  --tile-text: #1f5fd6;
  --tile-hover-bg: linear-gradient(135deg, rgba(43, 124, 255, 0.18), rgba(110, 198, 255, 0.14));

  --hero-bg:
    radial-gradient(1200px 600px at 80% -10%, rgba(14, 165, 233, 0.12), transparent 60%),
    radial-gradient(900px 500px at -10% 10%, rgba(43, 124, 255, 0.1), transparent 60%),
    var(--bg);
  --header-bg: rgba(255, 255, 255, 0.78);
  --screen-bg: linear-gradient(180deg, #ffffff 0%, #f2f6fd 100%);
  --btn-ghost-bg: rgba(43, 124, 255, 0.05);
  --btn-ghost-bg-hover: rgba(43, 124, 255, 0.1);

  --shadow: 0 10px 40px rgba(43, 92, 170, 0.12);
  --shadow-strong: 0 16px 48px rgba(43, 92, 170, 0.18);
  --cta-box-bg:
    radial-gradient(600px 300px at 30% 20%, rgba(43, 124, 255, 0.16), transparent 60%),
    radial-gradient(600px 300px at 80% 80%, rgba(14, 165, 233, 0.16), transparent 60%),
    linear-gradient(160deg, #ffffff 0%, #eaf3ff 100%);
  --cta-box-border: rgba(43, 124, 255, 0.2);

  --text-gradient: linear-gradient(180deg, #0f2749 0%, #3b5a8a 100%);

  --radius: 14px;
  color-scheme: light;
}

:root[data-theme="dark"] {
  --bg: #0b0d14;
  --bg-2: #11141d;
  --bg-3: #161a25;
  --card: #1a1f2c;
  --card-2: #1f2433;
  --line: rgba(255, 255, 255, 0.08);
  --line-soft: rgba(255, 255, 255, 0.05);

  --text: #e9ecf5;
  --text-dim: #a7adbf;
  --muted: #707789;

  --brand: #4f8cff;
  --brand-2: #7a5cff;
  --accent: #00d1b2;

  --grad: linear-gradient(135deg, #4f8cff 0%, #7a5cff 50%, #ff5fa2 100%);
  --grad-soft: linear-gradient(135deg, rgba(79, 140, 255, 0.14), rgba(122, 92, 255, 0.1));

  --pill-bg: rgba(79, 140, 255, 0.12);
  --pill-text: #b6ccff;
  --pill-border: rgba(79, 140, 255, 0.28);

  --tile-bg: linear-gradient(135deg, rgba(79, 140, 255, 0.14), rgba(122, 92, 255, 0.1));
  --tile-border: rgba(79, 140, 255, 0.25);
  --tile-text: #d9e3ff;
  --tile-hover-bg: linear-gradient(135deg, rgba(79, 140, 255, 0.22), rgba(122, 92, 255, 0.18));

  --hero-bg:
    radial-gradient(1200px 600px at 80% -10%, rgba(122, 92, 255, 0.18), transparent 60%),
    radial-gradient(900px 500px at -10% 10%, rgba(79, 140, 255, 0.15), transparent 60%),
    var(--bg);
  --header-bg: rgba(11, 13, 20, 0.7);
  --screen-bg: linear-gradient(180deg, #1a1f2c 0%, #10131b 100%);
  --btn-ghost-bg: rgba(255, 255, 255, 0.03);
  --btn-ghost-bg-hover: rgba(255, 255, 255, 0.07);

  --shadow: 0 10px 40px rgba(0, 0, 0, 0.35);
  --shadow-strong: 0 16px 48px rgba(0, 0, 0, 0.5);
  --cta-box-bg:
    radial-gradient(600px 300px at 30% 20%, rgba(79, 140, 255, 0.25), transparent 60%),
    radial-gradient(600px 300px at 80% 80%, rgba(122, 92, 255, 0.25), transparent 60%),
    linear-gradient(160deg, #1a1f2c 0%, #10131b 100%);
  --cta-box-border: rgba(122, 92, 255, 0.3);

  --text-gradient: linear-gradient(180deg, #ffffff 0%, #b3bfe4 100%);
  color-scheme: dark;
}

/* ============================================================
   Base
   ============================================================ */
* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  font-size: 16px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  scroll-behavior: smooth;
  transition: background .3s, color .3s;
}

body { background: var(--hero-bg); }

a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }

.container {
  max-width: 1180px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ============================================================
   Header
   ============================================================ */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  backdrop-filter: saturate(140%) blur(14px);
  -webkit-backdrop-filter: saturate(140%) blur(14px);
  background: var(--header-bg);
  border-bottom: 1px solid var(--line);
  transition: background .3s, border-color .3s;
}
.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}
.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  letter-spacing: 0.5px;
  color: var(--text);
}
.brand-logo {
  width: 32px;
  height: 32px;
  border-radius: 8px;
  object-fit: contain;
  background: var(--bg-2);
  padding: 2px;
  box-shadow: 0 4px 12px rgba(43, 124, 255, 0.18);
}
:root[data-theme="dark"] .brand-logo {
  background: rgba(255, 255, 255, 0.06);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.4);
}
.brand-text { font-size: 17px; }
.brand-accent { color: var(--brand); margin-left: 4px; font-weight: 700; }

.nav-links {
  display: flex;
  align-items: center;
  gap: 24px;
  font-size: 14.5px;
  color: var(--text-dim);
}
.nav-links a { transition: color .2s; }
.nav-links a:hover { color: var(--text); }

.btn-sm {
  padding: 8px 16px;
  border-radius: 999px;
  background: var(--grad);
  color: #fff !important;
  font-weight: 600;
  box-shadow: 0 6px 20px rgba(43, 124, 255, 0.3);
  transition: transform .2s, box-shadow .2s;
}
.btn-sm:hover { transform: translateY(-1px); box-shadow: 0 10px 24px rgba(43, 124, 255, 0.4); }

/* Theme & Lang toggles */
.theme-toggle,
.lang-toggle {
  width: 38px;
  height: 38px;
  border-radius: 999px;
  border: 1px solid var(--line);
  background: var(--btn-ghost-bg);
  color: var(--text);
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  position: relative;
  transition: background .2s, border-color .2s, transform .2s, color .2s;
  padding: 0;
  font-family: inherit;
}
.theme-toggle:hover {
  background: var(--btn-ghost-bg-hover);
  border-color: var(--brand);
  transform: rotate(15deg);
}
.lang-toggle {
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.3px;
  width: auto;
  min-width: 38px;
  padding: 0 12px;
}
.lang-toggle:hover {
  background: var(--btn-ghost-bg-hover);
  border-color: var(--brand);
  color: var(--brand);
}

/* 教程页：中文版提示（只在 EN 模式可见） */
.cn-only-note {
  display: none;
  margin: 0 0 1.5rem;
  padding: 12px 16px;
  background: var(--pill-bg);
  border: 1px solid var(--pill-border);
  border-radius: 10px;
  color: var(--pill-text);
  font-size: 14px;
  line-height: 1.6;
}
html[lang^="en"] .cn-only-note { display: block; }

/* 教程页：底色与字色跟随主题 */
.tut-page h1,
.tut-page h2,
.tut-page h3,
.tut-page strong { color: var(--text); }
.tut-page p,
.tut-page ul,
.tut-page ol { color: var(--text-dim); }
.tut-page .tut-meta { color: var(--muted); border-color: var(--line); }
.tut-page img { border-color: var(--line); }
.back-link { color: var(--brand); }
.tut-item { background: var(--card); border-color: var(--line); color: var(--text); }
.tut-item:hover { border-color: var(--brand); box-shadow: var(--shadow); }
.tut-item-body h3 { color: var(--text); }
.tut-item-body p { color: var(--text-dim); }
.tut-item-arrow { color: var(--muted); }
nav .active { color: var(--brand) !important; font-weight: 600; }
.theme-icon {
  position: absolute;
  font-size: 16px;
  line-height: 1;
  transition: opacity .25s, transform .25s;
}
:root[data-theme="light"] .theme-icon-sun { opacity: 1; transform: scale(1) rotate(0deg); }
:root[data-theme="light"] .theme-icon-moon { opacity: 0; transform: scale(0.5) rotate(90deg); }
:root[data-theme="dark"] .theme-icon-sun { opacity: 0; transform: scale(0.5) rotate(-90deg); }
:root[data-theme="dark"] .theme-icon-moon { opacity: 1; transform: scale(1) rotate(0deg); }

/* ============================================================
   Hero
   ============================================================ */
.hero {
  padding: 80px 0 60px;
  position: relative;
  overflow: hidden;
}
.hero-inner {
  display: grid;
  grid-template-columns: 1.1fr 1fr;
  gap: 64px;
  align-items: center;
}
.pill {
  display: inline-block;
  padding: 6px 14px;
  border-radius: 999px;
  background: var(--pill-bg);
  color: var(--pill-text);
  font-size: 13px;
  border: 1px solid var(--pill-border);
  margin-bottom: 20px;
}
.hero h1 {
  margin: 0 0 24px;
  display: flex;
  flex-direction: column;
  gap: 6px;
}
.h1-pre {
  font-size: 18px;
  font-weight: 500;
  color: var(--text-dim);
  letter-spacing: 2px;
  background: none;
  -webkit-background-clip: initial;
  background-clip: initial;
  -webkit-text-fill-color: currentColor;
  margin-bottom: 6px;
}
.h1-main {
  font-size: 50px;
  line-height: 1.1;
  font-weight: 800;
  letter-spacing: -1px;
  background: var(--text-gradient);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.h1-sub {
  font-size: 26px;
  line-height: 1.4;
  font-weight: 700;
  letter-spacing: 0.5px;
  background: var(--grad);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  margin-top: 4px;
}
.h1-sub .dot {
  margin: 0 6px;
  opacity: 0.55;
  font-weight: 400;
}
.lead strong { color: var(--brand); font-weight: 700; }
.lead {
  color: var(--text-dim);
  font-size: 17px;
  margin: 0 0 32px;
  max-width: 560px;
}

.cta-row {
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
  margin-bottom: 40px;
}
.cta-row.center { justify-content: center; }

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 22px;
  border-radius: 10px;
  font-weight: 600;
  font-size: 15px;
  cursor: pointer;
  transition: transform .18s, box-shadow .18s, background .18s, border-color .18s;
  border: 1px solid transparent;
}
.btn-lg { padding: 16px 28px; font-size: 16px; }
.btn-primary {
  background: var(--grad);
  color: #fff;
  box-shadow: 0 10px 30px rgba(43, 124, 255, 0.32);
}
.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 16px 36px rgba(43, 124, 255, 0.45);
}
.btn-ghost {
  border-color: var(--line);
  color: var(--text);
  background: var(--btn-ghost-bg);
}
.btn-ghost:hover {
  background: var(--btn-ghost-bg-hover);
  border-color: var(--brand);
  transform: translateY(-2px);
}

.hero-stats {
  display: flex;
  gap: 48px;
  padding-top: 24px;
  border-top: 1px solid var(--line);
}
.hero-stats > div { display: flex; flex-direction: column; }
.hero-stats b {
  font-size: 28px;
  font-weight: 800;
  background: var(--grad);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.hero-stats span { color: var(--text-dim); font-size: 13px; }

.hero-visual { position: relative; }
.screen {
  background: var(--screen-bg);
  border: 1px solid var(--line);
  border-radius: 18px;
  padding: 14px;
  box-shadow: var(--shadow-strong);
  position: relative;
  z-index: 2;
}
.screen-bar {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 0 4px 12px;
  border-bottom: 1px solid var(--line);
  margin-bottom: 14px;
}
.screen-bar i {
  width: 10px; height: 10px; border-radius: 50%; display: inline-block;
}
.screen-bar i:nth-child(1) { background: #ff5f57; }
.screen-bar i:nth-child(2) { background: #febc2e; }
.screen-bar i:nth-child(3) { background: #28c840; }
.screen-bar span {
  margin-left: auto;
  font-size: 12px;
  color: var(--muted);
}
.screen-body {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 10px;
  padding: 6px;
}
.tile {
  background: var(--tile-bg);
  border: 1px solid var(--tile-border);
  padding: 18px 12px;
  border-radius: 10px;
  text-align: center;
  font-size: 13.5px;
  font-weight: 600;
  color: var(--tile-text);
  transition: transform .25s, background .25s, box-shadow .25s;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 6px;
  min-height: 72px;
}
.tile:hover {
  transform: translateY(-3px);
  background: var(--tile-hover-bg);
  box-shadow: 0 8px 20px rgba(43, 124, 255, 0.15);
}
.tile-ico-sm { font-size: 20px; line-height: 1; }

.tile-hero {
  grid-column: span 3;
  background: var(--grad);
  color: #fff;
  border-color: transparent;
  padding: 20px 18px;
  text-align: left;
  flex-direction: column;
  align-items: flex-start;
  gap: 4px;
  position: relative;
  overflow: hidden;
  box-shadow: 0 10px 24px rgba(43, 124, 255, 0.28);
}
.tile-hero::after {
  content: "";
  position: absolute;
  right: -30px; top: -30px;
  width: 120px; height: 120px;
  background: radial-gradient(circle, rgba(255, 255, 255, 0.25), transparent 70%);
}
.tile-hero .tile-ico {
  font-size: 22px;
  line-height: 1;
  margin-bottom: 2px;
}
.tile-hero .tile-main {
  font-size: 17px;
  font-weight: 700;
  letter-spacing: 0.3px;
}
.tile-hero .tile-meta {
  font-size: 12px;
  opacity: 0.85;
  font-weight: 500;
}
.tile-hero .tile-bar {
  width: 100%;
  height: 4px;
  background: rgba(255, 255, 255, 0.25);
  border-radius: 99px;
  margin-top: 8px;
  overflow: hidden;
}
.tile-hero .tile-bar span {
  display: block;
  height: 100%;
  width: 68%;
  background: #fff;
  border-radius: 99px;
  animation: progressPulse 2.4s ease-in-out infinite;
}
@keyframes progressPulse {
  0%, 100% { width: 62%; opacity: 0.85; }
  50%      { width: 82%; opacity: 1; }
}

.glow {
  position: absolute;
  inset: -20px;
  background: radial-gradient(circle at 60% 40%, rgba(43, 124, 255, 0.22), transparent 60%);
  filter: blur(40px);
  z-index: 1;
}
:root[data-theme="dark"] .glow {
  background: radial-gradient(circle at 60% 40%, rgba(122, 92, 255, 0.35), transparent 60%);
}

/* ============================================================
   Sections
   ============================================================ */
.section {
  padding: 100px 0;
  position: relative;
}
.section-alt { background: var(--bg-2); }
.section-head {
  max-width: 720px;
  margin: 0 auto 56px;
  text-align: center;
}
.eyebrow {
  display: inline-block;
  padding: 5px 12px;
  font-size: 12px;
  letter-spacing: 1.5px;
  text-transform: uppercase;
  background: var(--pill-bg);
  color: var(--pill-text);
  border-radius: 999px;
  margin-bottom: 16px;
  border: 1px solid var(--pill-border);
}
.section-head h2 {
  font-size: 38px;
  font-weight: 800;
  margin: 0 0 14px;
  line-height: 1.2;
  letter-spacing: -0.3px;
  color: var(--text);
}
.section-head p {
  color: var(--text-dim);
  font-size: 17px;
  margin: 0;
}

/* Grids */
.grid-5 {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 16px;
}
.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 22px;
}

.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 28px 22px;
  transition: transform .25s, border-color .25s, background .25s, box-shadow .25s;
  box-shadow: 0 2px 8px rgba(43, 92, 170, 0.04);
}
:root[data-theme="dark"] .card { box-shadow: none; }
.card:hover {
  transform: translateY(-4px);
  border-color: var(--brand);
  background: var(--card-2);
  box-shadow: var(--shadow);
}
.card-icon {
  width: 48px; height: 48px;
  border-radius: 12px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 24px;
  background: var(--grad-soft);
  margin-bottom: 18px;
}
.card h3 {
  font-size: 17px;
  margin: 0 0 8px;
  font-weight: 700;
  color: var(--text);
}
.card p {
  color: var(--text-dim);
  font-size: 14.5px;
  margin: 0;
  line-height: 1.6;
}

/* Modes */
.mode-card {
  background: linear-gradient(160deg, var(--card) 0%, var(--card-2) 100%);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 36px 28px;
  position: relative;
  overflow: hidden;
  transition: transform .25s, box-shadow .25s;
  box-shadow: 0 2px 8px rgba(43, 92, 170, 0.04);
}
:root[data-theme="dark"] .mode-card { box-shadow: none; }
.mode-card:hover { transform: translateY(-4px); box-shadow: var(--shadow); }
.mode-card::before {
  content: "";
  position: absolute;
  top: 0; left: 0; right: 0; height: 3px;
  background: var(--grad);
}
.mode-num {
  font-size: 44px;
  font-weight: 800;
  background: var(--grad);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  margin-bottom: 8px;
  letter-spacing: -1px;
}
.mode-card h3 {
  font-size: 20px;
  font-weight: 700;
  margin: 0 0 10px;
  color: var(--text);
}
.mode-card p {
  color: var(--text-dim);
  font-size: 15px;
  margin: 0;
}

/* Toolkit */
.toolkit-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}
.tool-group {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 24px;
  transition: border-color .25s, background .25s, box-shadow .25s;
  box-shadow: 0 2px 8px rgba(43, 92, 170, 0.04);
}
:root[data-theme="dark"] .tool-group { box-shadow: none; }
.tool-group:hover {
  border-color: var(--brand);
  background: var(--card-2);
  box-shadow: var(--shadow);
}
.tool-group h4 {
  margin: 0 0 16px;
  font-size: 16px;
  font-weight: 700;
  letter-spacing: 0.2px;
  color: var(--text);
}
.tool-group ul {
  list-style: none;
  padding: 0;
  margin: 0;
}
.tool-group li {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 12px;
  padding: 10px 0;
  border-bottom: 1px dashed var(--line-soft);
  font-size: 14.5px;
}
.tool-group li:last-child { border-bottom: none; }
.tool-group li b { font-weight: 600; color: var(--text); }
.tool-group li span { color: var(--muted); font-size: 13px; text-align: right; }

/* Feat (why) — 与 .card 视觉语言对齐 */
.feat {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 30px 28px;
  transition: transform .25s, border-color .25s, box-shadow .25s;
  box-shadow: 0 2px 8px rgba(43, 92, 170, 0.04);
}
:root[data-theme="dark"] .feat { box-shadow: none; }
.feat:hover { transform: translateY(-4px); border-color: var(--brand); box-shadow: var(--shadow); }
.feat-icon {
  width: 52px; height: 52px;
  border-radius: 14px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 26px;
  background: var(--grad-soft);
  margin-bottom: 18px;
  border: 1px solid var(--pill-border);
}
.feat h3 {
  font-size: 19px;
  margin: 0 0 10px;
  font-weight: 700;
  color: var(--text);
}
.feat p {
  color: var(--text-dim);
  margin: 0;
  font-size: 15px;
  line-height: 1.7;
}

/* FAQ */
.faq-wrap { max-width: 820px; margin: 0 auto; }
.faq {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 0 24px;
  margin-bottom: 14px;
  transition: border-color .25s, box-shadow .25s;
  box-shadow: 0 2px 8px rgba(43, 92, 170, 0.04);
}
:root[data-theme="dark"] .faq { box-shadow: none; }
.faq[open] { border-color: var(--brand); box-shadow: var(--shadow); }
.faq summary {
  list-style: none;
  cursor: pointer;
  padding: 20px 0;
  font-size: 16px;
  font-weight: 600;
  display: flex;
  justify-content: space-between;
  align-items: center;
  color: var(--text);
}
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after {
  content: "+";
  font-size: 22px;
  color: var(--text-dim);
  transition: transform .25s;
}
.faq[open] summary::after { content: "−"; color: var(--brand); transform: rotate(180deg); }
.faq p {
  color: var(--text-dim);
  margin: 0;
  padding: 0 0 20px;
  font-size: 15px;
  line-height: 1.75;
}

/* CTA */
.section-cta { padding: 80px 0 100px; }
.cta-box {
  background: var(--cta-box-bg);
  border: 1px solid var(--cta-box-border);
  border-radius: 22px;
  padding: 56px 48px;
  text-align: center;
  box-shadow: var(--shadow-strong);
}
.cta-box h2 {
  font-size: 30px;
  margin: 0 0 14px;
  line-height: 1.3;
  font-weight: 800;
  letter-spacing: -0.2px;
  color: var(--text);
}
.cta-box > p {
  color: var(--text-dim);
  margin: 0 0 28px;
  font-size: 16px;
}
.cta-note {
  color: var(--muted);
  font-size: 13px;
  margin-top: 18px;
}

/* Footer */
.site-footer {
  background: var(--bg-2);
  border-top: 1px solid var(--line);
  padding: 56px 0 24px;
  color: var(--text-dim);
}
.foot {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 40px;
}
.foot .brand { margin-bottom: 14px; }
.foot .muted { color: var(--muted); font-size: 14px; max-width: 320px; }
.foot-links h5 {
  color: var(--text);
  font-size: 14px;
  margin: 8px 0 14px;
  font-weight: 700;
}
.foot-links a {
  display: block;
  color: var(--text-dim);
  font-size: 14px;
  padding: 5px 0;
  transition: color .2s;
}
.foot-links a:hover { color: var(--brand); }
.foot-base {
  margin-top: 40px;
  padding-top: 24px;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 13px;
  text-align: center;
}

/* Responsive */
@media (max-width: 960px) {
  .hero-inner { grid-template-columns: 1fr; gap: 40px; }
  .h1-main { font-size: 40px; }
  .h1-sub { font-size: 22px; }
  .h1-pre { font-size: 16px; letter-spacing: 1.5px; }
  .grid-5 { grid-template-columns: repeat(2, 1fr); }
  .grid-3, .toolkit-grid { grid-template-columns: 1fr 1fr; }
  .foot { grid-template-columns: 1fr 1fr; }
  .section { padding: 72px 0; }
  .section-head h2 { font-size: 30px; }
}
@media (max-width: 640px) {
  .nav-links { gap: 8px; font-size: 13.5px; }
  .nav-links a:not(.btn-sm) { display: none; }
  .nav-links .btn-sm {
    height: 34px;
    padding: 0 12px;
    display: inline-flex;
    align-items: center;
    font-size: 13px;
    white-space: nowrap;
    flex-shrink: 0;
    box-shadow: 0 4px 12px rgba(43, 124, 255, 0.25);
  }
  .theme-toggle, .lang-toggle { width: 34px; height: 34px; flex-shrink: 0; }
  .lang-toggle { width: auto; min-width: 34px; padding: 0 10px; font-size: 12px; }
  .brand { gap: 7px; min-width: 0; flex-shrink: 1; }
  .brand-text { font-size: 15px; white-space: nowrap; }
  .brand-logo { width: 28px; height: 28px; }
  .hero { padding: 56px 0 40px; }
  .h1-main { font-size: 28px; }
  .h1-sub { font-size: 17px; line-height: 1.5; }
  .h1-pre { font-size: 14px; letter-spacing: 1px; }
  .tile-hero .tile-main { font-size: 15px; }
  .screen-body { grid-template-columns: repeat(3, 1fr); }
  .hero-stats { gap: 24px; }
  .hero-stats b { font-size: 22px; }
  .grid-5, .grid-3, .toolkit-grid { grid-template-columns: 1fr; }
  .foot { grid-template-columns: 1fr; }
  .cta-box { padding: 40px 24px; }
  .cta-box h2 { font-size: 22px; }
  .section-head h2 { font-size: 26px; }
}
@media (max-width: 480px) {
  .site-header .container { padding: 0 12px; }
  .nav-links { gap: 6px; }
  .nav-links .btn-sm { height: 32px; padding: 0 10px; font-size: 12.5px; }
  .theme-toggle, .lang-toggle { width: 32px; height: 32px; }
  .lang-toggle { width: auto; min-width: 32px; padding: 0 9px; font-size: 11.5px; }
  .brand-text { font-size: 14px; }
  .brand-logo { width: 26px; height: 26px; }
}
@media (max-width: 340px) {
  .brand-text { display: none; }
}

/* ============================================================
   Entrance animations + reduced motion
   ============================================================ */
@keyframes fadeUp {
  from { opacity: 0; transform: translateY(18px); }
  to   { opacity: 1; transform: translateY(0); }
}
@keyframes fadeIn {
  from { opacity: 0; }
  to   { opacity: 1; }
}
@keyframes floatY {
  0%, 100% { transform: translateY(0); }
  50%      { transform: translateY(-8px); }
}

.hero-copy > * {
  opacity: 0;
  animation: fadeUp .7s cubic-bezier(.2,.7,.2,1) forwards;
}
.hero-copy .pill        { animation-delay: .05s; }
.hero-copy h1           { animation-delay: .15s; }
.hero-copy .lead        { animation-delay: .3s; }
.hero-copy .cta-row     { animation-delay: .45s; }
.hero-copy .hero-stats  { animation-delay: .6s; }
.hero-visual {
  opacity: 0;
  animation: fadeIn .9s ease-out .35s forwards;
}
.hero-visual .screen { animation: floatY 6s ease-in-out infinite; animation-delay: 1.2s; }

/* Reveal-on-scroll (no JS fallback: show by default) */
.reveal { opacity: 0; transform: translateY(18px); transition: opacity .7s ease, transform .7s ease; }
.reveal.in { opacity: 1; transform: none; }

/* Respect OS-level reduce motion */
@media (prefers-reduced-motion: reduce) {
  html, body { scroll-behavior: auto; }
  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
  }
  .hero-copy > *,
  .hero-visual { opacity: 1 !important; animation: none !important; }
  .tile-hero .tile-bar span { animation: none !important; width: 72% !important; }
}