/* ============================================
   比特彗星中文网 · Bit-Comet-cn
   冰蓝科技主题样式表
   ============================================ */

:root {
  --bg-0: #050d1f;
  --bg-1: #0a1530;
  --bg-2: #0f1c40;
  --line: rgba(99, 179, 237, 0.12);
  --line-2: rgba(34, 211, 238, 0.22);
  --text: #e6f1ff;
  --text-2: #9bb0d3;
  --text-3: #6b7ea3;
  --ice: #22d3ee;
  --ice-2: #06b6d4;
  --ice-deep: #0e7490;
  --violet: #818cf8;
  --violet-2: #6366f1;
  --glow: rgba(34, 211, 238, 0.45);
  --glow-soft: rgba(34, 211, 238, 0.18);
  --violet-glow: rgba(129, 140, 248, 0.35);
  --warn: #fbbf24;
  --good: #34d399;
  --bad: #f87171;
  --radius: 14px;
  --radius-lg: 20px;
  --shadow-card: 0 4px 24px rgba(0, 0, 0, 0.45);
  --shadow-card-hi: 0 8px 36px rgba(0, 0, 0, 0.55), 0 0 32px var(--glow-soft);
}

* { box-sizing: border-box; margin: 0; padding: 0; }

html, body {
  background: var(--bg-0);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", "Segoe UI", Roboto, sans-serif;
  font-size: 16px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

/* 背景：蓝色网格 + 径向辉光 */
body::before {
  content: ""; position: fixed; inset: 0; z-index: -2;
  background:
    radial-gradient(1100px 700px at 12% -10%, rgba(34, 211, 238, 0.16), transparent 60%),
    radial-gradient(900px 600px at 100% 8%, rgba(129, 140, 248, 0.14), transparent 60%),
    radial-gradient(1200px 800px at 50% 110%, rgba(6, 182, 212, 0.10), transparent 65%),
    linear-gradient(180deg, var(--bg-0) 0%, #03081a 100%);
}
body::after {
  content: ""; position: fixed; inset: 0; z-index: -1; pointer-events: none;
  background-image:
    linear-gradient(rgba(99, 179, 237, 0.05) 1px, transparent 1px),
    linear-gradient(90deg, rgba(99, 179, 237, 0.05) 1px, transparent 1px);
  background-size: 48px 48px;
  mask-image: radial-gradient(ellipse 80% 70% at 50% 35%, #000 30%, transparent 90%);
  -webkit-mask-image: radial-gradient(ellipse 80% 70% at 50% 35%, #000 30%, transparent 90%);
}

a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }
ul, ol { list-style: none; }

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

.section { padding: 80px 0; position: relative; }
.section-sm { padding: 56px 0; }

.eyebrow {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 6px 14px;
  background: rgba(34, 211, 238, 0.08);
  border: 1px solid var(--line-2);
  border-radius: 999px;
  font-size: 12.5px; font-weight: 600;
  color: var(--ice);
  letter-spacing: 0.5px;
  text-transform: uppercase;
}
.eyebrow::before { content: ""; width: 6px; height: 6px; border-radius: 50%; background: var(--ice); box-shadow: 0 0 10px var(--glow); }

h1, h2, h3, h4 { font-weight: 800; line-height: 1.25; letter-spacing: -0.01em; }
h1 { font-size: clamp(34px, 5vw, 54px); }
h2 { font-size: clamp(26px, 3.4vw, 36px); margin-bottom: 14px; }
h3 { font-size: 20px; margin-bottom: 8px; }

.section-title { text-align: center; margin-bottom: 48px; }
.section-title h2 {
  background: linear-gradient(135deg, #e6f1ff 0%, var(--ice) 60%, var(--violet) 100%);
  -webkit-background-clip: text; background-clip: text; color: transparent;
  margin-top: 12px;
}
.section-title p { color: var(--text-2); font-size: 15.5px; max-width: 640px; margin: 0 auto; }

/* ---------- 导航 ---------- */
.nav {
  position: sticky; top: 0; z-index: 100;
  background: rgba(5, 13, 31, 0.65);
  backdrop-filter: blur(18px) saturate(140%);
  -webkit-backdrop-filter: blur(18px) saturate(140%);
  border-bottom: 1px solid var(--line);
}
.nav-bar { display: flex; align-items: center; justify-content: space-between; height: 68px; }

.logo { display: flex; align-items: center; gap: 12px; }
.logo .logo-icon {
  width: 36px; height: 36px; flex: none; display: block;
  border-radius: 8px;
  filter: drop-shadow(0 0 8px var(--glow));
}
.logo-text { font-size: 19px; font-weight: 800; letter-spacing: 0.5px; color: var(--text); }
.logo-text em { font-style: normal; color: var(--ice); font-weight: 700; }

.nav-links { display: flex; gap: 4px; }
.nav-links a {
  padding: 8px 16px; border-radius: 9px; font-size: 14.5px;
  color: var(--text-2); transition: all 0.2s;
}
.nav-links a:hover { color: var(--text); background: rgba(34, 211, 238, 0.06); }
.nav-links a.active { color: var(--ice); background: rgba(34, 211, 238, 0.1); }

.nav-toggle { display: none; background: transparent; border: none; color: var(--text); font-size: 22px; cursor: pointer; }

@media (max-width: 820px) {
  .nav-toggle { display: block; }
  .nav-links {
    position: absolute; top: 68px; left: 0; right: 0; flex-direction: column;
    background: rgba(5, 13, 31, 0.95); backdrop-filter: blur(20px);
    padding: 16px 24px; gap: 8px;
    border-bottom: 1px solid var(--line);
    display: none;
  }
  .nav-links.open { display: flex; }
  .nav-links a { display: block; padding: 12px 16px; }
}

/* ---------- Hero（满屏背景 + 浮窗） ---------- */
/* Hero：左文 + 右图（自适应，桌面并排/移动端堆叠） */
.hero { padding: 88px 0 60px; }
.hero > .container {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  gap: 48px;
  align-items: center;
}
.hero-inner { position: relative; z-index: 2; min-width: 0; }
.hero h1 { margin: 18px 0 20px; }
.hero h1 span {
  background: linear-gradient(120deg, var(--ice) 0%, var(--violet) 100%);
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.hero p.lead { font-size: 18px; color: var(--text-2); max-width: 640px; margin-bottom: 32px; }
.hero-actions { display: flex; gap: 14px; flex-wrap: wrap; margin-bottom: 36px; }

.btn-primary {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 14px 30px; border-radius: 11px;
  background: linear-gradient(135deg, var(--ice) 0%, var(--ice-2) 100%);
  color: #001428; font-weight: 800; font-size: 15.5px;
  box-shadow: 0 8px 26px var(--glow), inset 0 1px 0 rgba(255,255,255,0.3);
  transition: all 0.25s;
}
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 12px 36px var(--glow), inset 0 1px 0 rgba(255,255,255,0.4); color: #001428; }

.btn-ghost {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 14px 28px; border-radius: 11px;
  background: rgba(34, 211, 238, 0.06);
  border: 1px solid var(--line-2);
  color: var(--text); font-weight: 600;
  transition: all 0.2s;
}
.btn-ghost:hover { background: rgba(34, 211, 238, 0.12); border-color: var(--ice); color: var(--ice); }

/* 截图卡：右上角带 3D 透视，宽度按列自适应 */
.hero-shot {
  position: relative;
  width: 100%;
  max-width: 560px;
  justify-self: end;
  border-radius: var(--radius-lg);
  background: linear-gradient(135deg, rgba(34, 211, 238, 0.18), rgba(129, 140, 248, 0.18));
  padding: 2px;
  box-shadow: 0 30px 80px rgba(0, 0, 0, 0.55), 0 0 60px rgba(34, 211, 238, 0.18);
  transform: perspective(1200px) rotateY(-5deg) rotateX(2deg);
  transition: transform 0.4s;
}
.hero-shot:hover { transform: perspective(1200px) rotateY(0deg) rotateX(0deg); }
.hero-shot-inner {
  background: var(--bg-1); border-radius: 18px; padding: 14px;
}
.hero-shot-inner .browser-bar {
  display: flex; align-items: center; gap: 6px; padding: 4px 8px 12px;
}
.hero-shot-inner .browser-bar span {
  width: 10px; height: 10px; border-radius: 50%; background: var(--text-3); opacity: 0.5;
}
/* 关键：按原图比例锁死纵横比，宽度自适应 */
.hero-shot-inner .shot-frame {
  aspect-ratio: 900 / 596;
  width: 100%;
  display: block;
}
.hero-shot-inner .shot-frame img {
  width: 100%; height: 100%; display: block; border-radius: 10px; object-fit: cover;
}

/* 窄屏：堆叠为单列，截图下方整宽显示 */
@media (max-width: 900px) {
  .hero > .container { grid-template-columns: 1fr; gap: 32px; }
  .hero-shot {
    justify-self: stretch;
    max-width: 100%;
    transform: none;
  }
  .hero-shot:hover { transform: none; }
}
@media (max-width: 480px) {
  .hero { padding: 56px 0 40px; }
  .hero-actions .btn-primary, .hero-actions .btn-ghost { flex: 1; justify-content: center; }
}

/* ---------- 信任指标条 ---------- */
.trust {
  background: linear-gradient(90deg, rgba(34, 211, 238, 0.04), rgba(129, 140, 248, 0.04));
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  padding: 28px 0;
}
.trust-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; }
.trust-item { text-align: center; }
.trust-item .num {
  font-size: 30px; font-weight: 800;
  background: linear-gradient(135deg, var(--ice), var(--violet));
  -webkit-background-clip: text; background-clip: text; color: transparent;
  line-height: 1.1;
}
.trust-item .lbl { color: var(--text-2); font-size: 13.5px; margin-top: 4px; }
@media (max-width: 720px) { .trust-grid { grid-template-columns: repeat(2, 1fr); } }

/* ---------- 功能特性卡片（4列） ---------- */
.feat-grid {
  display: grid; grid-template-columns: repeat(4, 1fr); gap: 18px;
}
.feat-card {
  position: relative;
  background: linear-gradient(180deg, rgba(15, 28, 64, 0.7), rgba(10, 21, 48, 0.7));
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 24px 22px;
  transition: all 0.3s;
  overflow: hidden;
}
.feat-card::before {
  content: ""; position: absolute; inset: 0;
  background: linear-gradient(135deg, var(--glow-soft), transparent 60%);
  opacity: 0; transition: opacity 0.3s;
}
.feat-card:hover { border-color: var(--ice); transform: translateY(-4px); box-shadow: var(--shadow-card-hi); }
.feat-card:hover::before { opacity: 1; }

.feat-icon {
  width: 44px; height: 44px; border-radius: 10px;
  background: linear-gradient(135deg, rgba(34, 211, 238, 0.18), rgba(129, 140, 248, 0.18));
  border: 1px solid var(--line-2);
  display: flex; align-items: center; justify-content: center;
  font-size: 22px; margin-bottom: 14px; position: relative; z-index: 1;
}
.feat-card h3 { font-size: 17px; position: relative; z-index: 1; }
.feat-card p { color: var(--text-2); font-size: 14px; line-height: 1.6; margin-top: 6px; position: relative; z-index: 1; }

@media (max-width: 980px) { .feat-grid { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 560px) { .feat-grid { grid-template-columns: 1fr; } }

/* ---------- 工作流程时间线 ---------- */
.flow { display: grid; grid-template-columns: repeat(5, 1fr); gap: 16px; }
.flow-step {
  position: relative;
  background: var(--bg-1); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 22px 18px; text-align: center;
}
.flow-step .idx {
  position: absolute; top: -14px; left: 50%; transform: translateX(-50%);
  width: 30px; height: 30px; border-radius: 50%;
  background: linear-gradient(135deg, var(--ice), var(--ice-2));
  color: #001428; font-weight: 800; font-size: 14px;
  display: flex; align-items: center; justify-content: center;
  box-shadow: 0 0 16px var(--glow);
}
.flow-step h4 { font-size: 15px; margin: 8px 0 6px; }
.flow-step p { font-size: 13px; color: var(--text-2); line-height: 1.55; }

@media (max-width: 980px) { .flow { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 560px) { .flow { grid-template-columns: 1fr; } }

/* ---------- 亮点左右分栏 ---------- */
.split { display: grid; grid-template-columns: 1fr 1fr; gap: 48px; align-items: center; }
.split-text h2 { margin-bottom: 16px; }
.split-text p { color: var(--text-2); margin-bottom: 14px; }
.split-text ul { margin-top: 18px; }
.split-text li {
  position: relative; padding-left: 26px; margin-bottom: 12px;
  color: var(--text-2);
}
.split-text li::before {
  content: "›"; position: absolute; left: 0; top: -1px;
  color: var(--ice); font-weight: 800; font-size: 18px;
}

.split-img {
  border-radius: var(--radius-lg);
  background: linear-gradient(135deg, rgba(34, 211, 238, 0.18), rgba(129, 140, 248, 0.18));
  padding: 2px;
  box-shadow: 0 24px 60px rgba(0,0,0,0.5);
}
.split-img-inner {
  background: var(--bg-1); border-radius: 18px; padding: 14px;
}
.split-img-inner img { width: 100%; border-radius: 10px; aspect-ratio: 900 / 596; }
.split-img-inner .shot-frame {
  aspect-ratio: 900 / 596; width: 100%; display: block;
}
.split-img-inner .shot-frame img {
  width: 100%; height: 100%; display: block; border-radius: 10px; object-fit: cover;
}

@media (max-width: 900px) { .split { grid-template-columns: 1fr; gap: 28px; } }

/* ---------- CTA 横幅 ---------- */
.cta-banner {
  background:
    radial-gradient(800px 400px at 20% 30%, var(--glow-soft), transparent 60%),
    radial-gradient(700px 380px at 80% 70%, rgba(129, 140, 248, 0.18), transparent 60%),
    linear-gradient(135deg, var(--bg-2), var(--bg-1));
  border: 1px solid var(--line-2);
  border-radius: var(--radius-lg);
  padding: 56px 48px;
  text-align: center;
  position: relative;
  overflow: hidden;
}
.cta-banner h2 { margin-bottom: 12px; }
.cta-banner p { color: var(--text-2); max-width: 540px; margin: 0 auto 28px; }

/* ---------- 下载页：分流卡 ---------- */
.dl-card {
  background: linear-gradient(180deg, rgba(15, 28, 64, 0.85), rgba(10, 21, 48, 0.85));
  border: 1px solid var(--line-2);
  border-radius: var(--radius-lg);
  padding: 48px;
  text-align: center;
  position: relative;
  overflow: hidden;
}
.dl-card::before {
  content: ""; position: absolute; inset: 0;
  background: radial-gradient(600px 300px at 50% 0%, rgba(34, 211, 238, 0.15), transparent 70%);
}
.dl-card h2 { position: relative; }
.dl-card p { color: var(--text-2); position: relative; margin: 14px auto 32px; max-width: 520px; }

.dl-meta {
  display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px;
  margin-top: 36px; position: relative;
}
.dl-meta div {
  background: rgba(5, 13, 31, 0.5);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 16px 12px;
}
.dl-meta .k { color: var(--text-3); font-size: 12.5px; text-transform: uppercase; letter-spacing: 0.5px; }
.dl-meta .v { color: var(--text); font-weight: 700; font-size: 16px; margin-top: 4px; }

@media (max-width: 640px) { .dl-card { padding: 32px 22px; } .dl-meta { grid-template-columns: 1fr; } }

/* ---------- 表格 ---------- */
.spec-table {
  width: 100%; border-collapse: collapse;
  background: var(--bg-1); border: 1px solid var(--line);
  border-radius: var(--radius); overflow: hidden;
}
.spec-table th, .spec-table td { padding: 14px 20px; text-align: left; font-size: 14.5px; border-bottom: 1px solid var(--line); }
.spec-table th { background: rgba(34, 211, 238, 0.06); color: var(--ice); font-weight: 700; font-size: 13px; text-transform: uppercase; letter-spacing: 0.5px; }
.spec-table tr:last-child td { border-bottom: none; }
.spec-table td:first-child { color: var(--text-2); width: 36%; }

/* ---------- FAQ 手风琴 ---------- */
.faq-list { max-width: 860px; margin: 0 auto; }
.faq-item {
  background: var(--bg-1); border: 1px solid var(--line);
  border-radius: var(--radius);
  margin-bottom: 12px;
  overflow: hidden;
  transition: border-color 0.2s;
}
.faq-item[open] { border-color: var(--line-2); }
.faq-item summary {
  padding: 20px 24px; cursor: pointer; font-weight: 700; font-size: 16px;
  list-style: none; position: relative;
  color: var(--text);
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after {
  content: "+"; position: absolute; right: 24px; top: 50%; transform: translateY(-50%);
  color: var(--ice); font-size: 22px; font-weight: 400;
  transition: transform 0.2s;
}
.faq-item[open] summary::after { content: "−"; }
.faq-item .faq-body { padding: 0 24px 22px; color: var(--text-2); line-height: 1.7; font-size: 14.5px; }
.faq-item .faq-body p { margin-bottom: 8px; }
.faq-item .faq-body p:last-child { margin-bottom: 0; }
.faq-item .faq-body strong { color: var(--text); }

/* ---------- 教程步骤 ---------- */
.tut-list { max-width: 820px; margin: 0 auto; }
.tut-step {
  display: grid; grid-template-columns: 56px 1fr; gap: 20px;
  background: var(--bg-1); border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 24px 26px;
  margin-bottom: 16px;
}
.tut-num {
  width: 44px; height: 44px; border-radius: 12px;
  background: linear-gradient(135deg, var(--ice), var(--ice-2));
  color: #001428; font-weight: 800; font-size: 18px;
  display: flex; align-items: center; justify-content: center;
  box-shadow: 0 0 16px var(--glow);
}
.tut-step h3 { font-size: 17px; }
.tut-step p { color: var(--text-2); font-size: 14.5px; margin-top: 6px; line-height: 1.7; }

@media (max-width: 560px) { .tut-step { grid-template-columns: 1fr; } }

/* ---------- 面包屑 ---------- */
.breadcrumb { padding: 18px 0; color: var(--text-3); font-size: 13.5px; }
.breadcrumb a { color: var(--text-2); }
.breadcrumb a:hover { color: var(--ice); }
.breadcrumb .sep { margin: 0 8px; opacity: 0.5; }

/* ---------- 页脚 ---------- */
.footer {
  background: linear-gradient(180deg, transparent, rgba(5, 13, 31, 0.8));
  border-top: 1px solid var(--line);
  padding: 56px 0 28px; margin-top: 80px;
}
.footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 36px; margin-bottom: 36px; }
.footer-brand p { color: var(--text-2); font-size: 14px; margin-top: 12px; max-width: 320px; }
.footer-col h4 { font-size: 14px; color: var(--ice); margin-bottom: 14px; text-transform: uppercase; letter-spacing: 0.5px; }
.footer-col a { display: block; color: var(--text-2); font-size: 14px; padding: 5px 0; }
.footer-col a:hover { color: var(--ice); }
.footer-bottom {
  padding-top: 22px; border-top: 1px solid var(--line);
  display: flex; justify-content: space-between; align-items: center;
  color: var(--text-3); font-size: 13px;
}
.footer-links a { color: var(--text-2); margin-left: 18px; }
.footer-links a:hover { color: var(--ice); }

@media (max-width: 760px) { .footer-grid { grid-template-columns: 1fr 1fr; } .footer-bottom { flex-direction: column; gap: 10px; } }

/* ---------- 文本块 ---------- */
.lead-lg { font-size: 17px; color: var(--text-2); line-height: 1.75; }
.text-muted { color: var(--text-2); }
.prose p { color: var(--text-2); margin-bottom: 14px; line-height: 1.75; }
.prose strong { color: var(--text); }
.prose ul { margin: 12px 0 12px 22px; list-style: disc; color: var(--text-2); }
.prose li { margin-bottom: 6px; }