/* ==========================================================================
   17C一起草 — 共享设计系统
   现代暗色视频社区 · 珊瑚红 × 春芽绿 × 暖琥珀
   ========================================================================== */

/* ---------- 设计令牌 ---------- */
:root {
  /* 背景层级 */
  --bg: #0A0B14;
  --bg-elevated: #11121E;
  --surface: #181A28;
  --surface-2: #20222F;
  --surface-3: #2A2C3D;
  --border: rgba(255, 255, 255, 0.08);
  --border-strong: rgba(255, 255, 255, 0.16);
  --glass: rgba(20, 22, 34, 0.72);

  /* 文字 */
  --text: #F5F5F7;
  --text-muted: #A0A3B5;
  --text-dim: #6C6F82;

  /* 品牌色 */
  --brand: #FF4D5E;
  --brand-soft: #FF6B7A;
  --brand-2: #00D97E;
  --brand-2-soft: #2EE69A;
  --brand-3: #FFB547;
  --brand-glow: rgba(255, 77, 94, 0.35);
  --brand-2-glow: rgba(0, 217, 126, 0.28);

  /* 渐变 */
  --grad-warm: linear-gradient(135deg, #FF4D5E 0%, #FF6B4A 45%, #FFB547 100%);
  --grad-cool: linear-gradient(135deg, #00D97E 0%, #00B4D8 100%);
  --grad-brand: linear-gradient(135deg, #FF4D5E 0%, #FFB547 100%);
  --grad-grass: linear-gradient(135deg, #00D97E 0%, #00C2A8 100%);
  --grad-dark: linear-gradient(180deg, #0A0B14 0%, #11121E 100%);
  --grad-mesh: radial-gradient(at 0% 0%, rgba(255,77,94,0.16) 0px, transparent 50%),
               radial-gradient(at 100% 0%, rgba(0,217,126,0.12) 0px, transparent 50%),
               radial-gradient(at 50% 100%, rgba(255,181,71,0.10) 0px, transparent 50%);

  /* 阴影 */
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.35);
  --shadow-lg: 0 20px 50px rgba(0, 0, 0, 0.45);
  --shadow-brand: 0 12px 32px rgba(255, 77, 94, 0.28);
  --shadow-grass: 0 12px 32px rgba(0, 217, 126, 0.22);

  /* 间距 / 圆角 */
  --radius-sm: 10px;
  --radius: 16px;
  --radius-lg: 24px;
  --radius-xl: 32px;
  --radius-pill: 999px;

  /* 字体 */
  --font-display: 'Sora', 'Noto Sans SC', system-ui, sans-serif;
  --font-body: 'Noto Sans SC', 'Sora', system-ui, sans-serif;

  /* 容器 */
  --container: 1240px;
  --nav-h: 72px;
}

/* ---------- 重置 ---------- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  font-family: var(--font-body);
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}
img, svg { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
button { font-family: inherit; cursor: pointer; border: none; background: none; color: inherit; }
ul, ol { list-style: none; }
::selection { background: var(--brand); color: #fff; }

/* 滚动条 */
::-webkit-scrollbar { width: 10px; height: 10px; }
::-webkit-scrollbar-track { background: var(--bg); }
::-webkit-scrollbar-thumb { background: var(--surface-3); border-radius: 10px; border: 2px solid var(--bg); }
::-webkit-scrollbar-thumb:hover { background: var(--brand); }

/* ---------- 排版 ---------- */
h1, h2, h3, h4, h5 { font-family: var(--font-display); font-weight: 800; line-height: 1.15; letter-spacing: -0.02em; }
.gradient-text {
  background: var(--grad-brand);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}
.gradient-text-cool {
  background: var(--grad-cool);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

/* ---------- 布局工具 ---------- */
.container { width: 100%; max-width: var(--container); margin: 0 auto; padding: 0 24px; }
.section { padding: 96px 0; position: relative; }
.section-sm { padding: 64px 0; }
.grid { display: grid; gap: 24px; }
.flex { display: flex; }
.center { display: flex; align-items: center; justify-content: center; }
.between { display: flex; align-items: center; justify-content: space-between; }
.wrap { flex-wrap: wrap; }
.gap-sm { gap: 12px; } .gap { gap: 24px; } .gap-lg { gap: 40px; }

/* ---------- 导航栏 ---------- */
.nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  height: var(--nav-h);
  display: flex; align-items: center;
  transition: background 0.3s, border-color 0.3s, backdrop-filter 0.3s;
  border-bottom: 1px solid transparent;
}
.nav.scrolled {
  background: var(--glass);
  backdrop-filter: blur(20px) saturate(180%);
  -webkit-backdrop-filter: blur(20px) saturate(180%);
  border-bottom-color: var(--border);
}
.nav-inner { width: 100%; max-width: var(--container); margin: 0 auto; padding: 0 24px; display: flex; align-items: center; justify-content: space-between; }

.logo { display: flex; align-items: center; gap: 10px; font-family: var(--font-display); font-weight: 800; font-size: 20px; }
.logo-badge {
  width: 38px; height: 38px; border-radius: 11px;
  background: var(--grad-brand);
  display: flex; align-items: center; justify-content: center;
  font-size: 14px; font-weight: 800; color: #fff;
  box-shadow: var(--shadow-brand);
  position: relative; overflow: hidden;
}
.logo-badge::after {
  content: ''; position: absolute; inset: 0;
  background: linear-gradient(120deg, transparent 30%, rgba(255,255,255,0.35) 50%, transparent 70%);
  transform: translateX(-100%);
  animation: shine 4s ease-in-out infinite;
}
@keyframes shine { 0%,100% { transform: translateX(-100%); } 50% { transform: translateX(100%); } }
.logo-badge svg { position: relative; z-index: 1; }
.logo-text span { color: var(--brand-soft); }

.nav-links { display: flex; align-items: center; gap: 4px; }
.nav-link {
  padding: 8px 16px; border-radius: var(--radius-pill);
  font-size: 15px; font-weight: 500; color: var(--text-muted);
  transition: color 0.2s, background 0.2s;
  display: flex; align-items: center; gap: 6px;
}
.nav-link:hover { color: var(--text); background: var(--surface); }
.nav-link.active { color: #fff; background: var(--surface-2); }

.nav-actions { display: flex; align-items: center; gap: 12px; }
.nav-search {
  display: flex; align-items: center; gap: 8px;
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius-pill); padding: 8px 16px;
  transition: border-color 0.2s, background 0.2s;
}
.nav-search:focus-within { border-color: var(--brand); background: var(--surface-2); }
.nav-search input {
  background: none; border: none; outline: none; color: var(--text);
  font-family: inherit; font-size: 14px; width: 160px;
}
.nav-search input::placeholder { color: var(--text-dim); }

.nav-toggle { display: none; width: 44px; height: 44px; border-radius: 12px; align-items: center; justify-content: center; background: var(--surface); border: 1px solid var(--border); }
.nav-toggle svg { width: 22px; height: 22px; }

/* 移动端菜单 */
.mobile-menu {
  position: fixed; top: var(--nav-h); left: 0; right: 0; z-index: 99;
  background: var(--glass); backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border);
  padding: 16px 24px; display: none; flex-direction: column; gap: 8px;
}
.mobile-menu.open { display: flex; }
.mobile-menu a { padding: 14px 16px; border-radius: 12px; font-weight: 500; }
.mobile-menu a:hover, .mobile-menu a.active { background: var(--surface); }

/* ---------- 按钮 ---------- */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  padding: 14px 28px; border-radius: var(--radius-pill);
  font-family: var(--font-display); font-weight: 700; font-size: 15px;
  transition: transform 0.2s, box-shadow 0.2s, background 0.2s;
  white-space: nowrap; cursor: pointer;
}
.btn svg { width: 18px; height: 18px; }
.btn-primary {
  background: var(--grad-brand); color: #fff;
  box-shadow: var(--shadow-brand);
}
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 16px 40px rgba(255,77,94,0.4); }
.btn-grass {
  background: var(--grad-grass); color: #06231A;
  box-shadow: var(--shadow-grass);
}
.btn-grass:hover { transform: translateY(-2px); box-shadow: 0 16px 40px rgba(0,217,126,0.35); }
.btn-ghost {
  background: var(--surface); color: var(--text); border: 1px solid var(--border-strong);
}
.btn-ghost:hover { background: var(--surface-2); border-color: var(--brand); transform: translateY(-2px); }
.btn-lg { padding: 16px 36px; font-size: 16px; }
.btn-sm { padding: 10px 20px; font-size: 14px; }

/* ---------- 区块标题 ---------- */
.section-head { margin-bottom: 48px; }
.eyebrow {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 6px 14px; border-radius: var(--radius-pill);
  background: var(--surface); border: 1px solid var(--border);
  font-size: 13px; font-weight: 600; color: var(--brand-soft);
  margin-bottom: 18px;
}
.eyebrow::before { content: ''; width: 6px; height: 6px; border-radius: 50%; background: var(--brand); box-shadow: 0 0 8px var(--brand); }
.eyebrow.cool { color: var(--brand-2-soft); }
.eyebrow.cool::before { background: var(--brand-2); box-shadow: 0 0 8px var(--brand-2); }

.section-title { font-size: clamp(28px, 4vw, 44px); }
.section-desc { color: var(--text-muted); font-size: 17px; max-width: 640px; margin-top: 14px; }

/* ---------- 卡片 ---------- */
.card {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius-lg); transition: transform 0.3s, border-color 0.3s, box-shadow 0.3s;
}
.card-hover:hover { transform: translateY(-6px); border-color: var(--border-strong); box-shadow: var(--shadow-lg); }

/* 视频卡片 */
.vcard {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius-lg); overflow: hidden; cursor: pointer;
  transition: transform 0.3s, border-color 0.3s, box-shadow 0.3s;
}
.vcard:hover { transform: translateY(-6px); border-color: var(--brand); box-shadow: var(--shadow-brand); }
.vcard-thumb {
  aspect-ratio: 16/9; position: relative; overflow: hidden;
  display: flex; align-items: center; justify-content: center;
}
.vcard-thumb .thumb-bg { position: absolute; inset: 0; }
.vcard-thumb .play-btn {
  position: relative; z-index: 2; width: 56px; height: 56px; border-radius: 50%;
  background: rgba(0,0,0,0.55); backdrop-filter: blur(8px);
  display: flex; align-items: center; justify-content: center;
  opacity: 0; transform: scale(0.8); transition: opacity 0.3s, transform 0.3s;
}
.vcard:hover .play-btn { opacity: 1; transform: scale(1); }
.vcard-thumb .duration {
  position: absolute; bottom: 10px; right: 10px; z-index: 2;
  background: rgba(0,0,0,0.7); backdrop-filter: blur(4px);
  padding: 3px 8px; border-radius: 6px; font-size: 12px; font-weight: 600;
}
.vcard-thumb .tag {
  position: absolute; top: 10px; left: 10px; z-index: 2;
  padding: 4px 10px; border-radius: var(--radius-pill);
  font-size: 12px; font-weight: 600; color: #fff;
  background: rgba(0,0,0,0.5); backdrop-filter: blur(4px);
}
.vcard-body { padding: 16px; }
.vcard-title { font-size: 15px; font-weight: 600; line-height: 1.4; margin-bottom: 10px; display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden; }
.vcard-meta { display: flex; align-items: center; gap: 8px; color: var(--text-dim); font-size: 13px; }
.vcard-avatar { width: 24px; height: 24px; border-radius: 50%; flex-shrink: 0; }

/* ---------- 页脚 ---------- */
.footer { border-top: 1px solid var(--border); background: var(--bg-elevated); padding: 64px 0 32px; margin-top: 40px; }
.footer-grid { display: grid; grid-template-columns: 1.6fr repeat(3, 1fr); gap: 48px; margin-bottom: 48px; }
.footer-brand .logo { margin-bottom: 16px; }
.footer-desc { color: var(--text-muted); font-size: 14px; max-width: 320px; line-height: 1.7; }
.footer-col h4 { font-size: 14px; margin-bottom: 18px; color: var(--text); }
.footer-col li { margin-bottom: 10px; }
.footer-col a { color: var(--text-muted); font-size: 14px; transition: color 0.2s; }
.footer-col a:hover { color: var(--brand-soft); }
.footer-bottom { border-top: 1px solid var(--border); padding-top: 24px; display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap; gap: 12px; color: var(--text-dim); font-size: 13px; }
.footer-socials { display: flex; gap: 10px; }
.footer-socials a { width: 38px; height: 38px; border-radius: 10px; background: var(--surface); border: 1px solid var(--border); display: flex; align-items: center; justify-content: center; transition: all 0.2s; }
.footer-socials a:hover { background: var(--brand); border-color: var(--brand); transform: translateY(-2px); }
.footer-socials svg { width: 18px; height: 18px; }

/* ---------- 滚动揭示动画 ---------- */
.reveal { opacity: 0; transform: translateY(30px); transition: opacity 0.7s cubic-bezier(0.16,1,0.3,1), transform 0.7s cubic-bezier(0.16,1,0.3,1); }
.reveal.visible { opacity: 1; transform: translateY(0); }
.reveal-delay-1 { transition-delay: 0.08s; }
.reveal-delay-2 { transition-delay: 0.16s; }
.reveal-delay-3 { transition-delay: 0.24s; }
.reveal-delay-4 { transition-delay: 0.32s; }
.reveal-delay-5 { transition-delay: 0.4s; }

/* ---------- 背景特效 ---------- */
.bg-mesh { position: fixed; inset: 0; z-index: -1; background: var(--grad-mesh); pointer-events: none; }
.bg-grid {
  position: fixed; inset: 0; z-index: -1; pointer-events: none;
  background-image: linear-gradient(rgba(255,255,255,0.025) 1px, transparent 1px), linear-gradient(90deg, rgba(255,255,255,0.025) 1px, transparent 1px);
  background-size: 60px 60px;
  mask-image: radial-gradient(ellipse 80% 60% at 50% 0%, #000 30%, transparent 75%);
  -webkit-mask-image: radial-gradient(ellipse 80% 60% at 50% 0%, #000 30%, transparent 75%);
}

/* 浮动光斑 */
.orb { position: absolute; border-radius: 50%; filter: blur(60px); opacity: 0.4; pointer-events: none; animation: float 8s ease-in-out infinite; }
@keyframes float { 0%,100% { transform: translate(0,0); } 50% { transform: translate(30px,-40px); } }

/* ---------- 回到顶部 ---------- */
.back-top {
  position: fixed; bottom: 28px; right: 28px; z-index: 90;
  width: 48px; height: 48px; border-radius: 14px;
  background: var(--grad-brand); color: #fff;
  display: flex; align-items: center; justify-content: center;
  box-shadow: var(--shadow-brand);
  opacity: 0; transform: translateY(20px) scale(0.8); pointer-events: none;
  transition: opacity 0.3s, transform 0.3s;
}
.back-top.show { opacity: 1; transform: translateY(0) scale(1); pointer-events: auto; }
.back-top:hover { transform: translateY(-3px) scale(1.05); }
.back-top svg { width: 22px; height: 22px; }

/* ---------- 通用缩略图渐变背景 ---------- */
.thumb-grad-1 { background: linear-gradient(135deg,#FF4D5E,#FF6B4A); }
.thumb-grad-2 { background: linear-gradient(135deg,#00D97E,#00B4D8); }
.thumb-grad-3 { background: linear-gradient(135deg,#6C5CE7,#00D97E); }
.thumb-grad-4 { background: linear-gradient(135deg,#FFB547,#FF4D5E); }
.thumb-grad-5 { background: linear-gradient(135deg,#00B4D8,#6C5CE7); }
.thumb-grad-6 { background: linear-gradient(135deg,#FF6B7A,#FFB547); }
.thumb-grad-7 { background: linear-gradient(135deg,#00C2A8,#00B4D8); }
.thumb-grad-8 { background: linear-gradient(135deg,#FF4D5E,#6C5CE7); }

/* 播放图标 */
.play-icon { width: 22px; height: 22px; fill: #fff; }

/* ==========================================================================
   响应式
   ========================================================================== */
@media (max-width: 1024px) {
  .footer-grid { grid-template-columns: 1fr 1fr; gap: 32px; }
}

@media (max-width: 768px) {
  :root { --nav-h: 64px; }
  .section { padding: 64px 0; }
  .container { padding: 0 18px; }
  .nav-links, .nav-search { display: none; }
  .nav-toggle { display: flex; }
  .nav-actions .btn-ghost { display: none; }
  .section-head { margin-bottom: 36px; }
  .footer-grid { grid-template-columns: 1fr; gap: 28px; }
  .footer-bottom { flex-direction: column; align-items: flex-start; }
  .btn { padding: 13px 22px; font-size: 14px; }
  .btn-lg { padding: 15px 28px; font-size: 15px; }
  .back-top { bottom: 20px; right: 20px; width: 44px; height: 44px; }
}

@media (max-width: 480px) {
  .logo-text { font-size: 17px; }
  .logo-badge { width: 34px; height: 34px; }
}