/* ============================================================
   Ventoy 中文站 - 全局样式
   深蓝科技风 / 响应式
   ============================================================ */
:root {
  --primary: #1565d8;
  --primary-dark: #0d47a1;
  --primary-light: #5b9bf0;
  --accent: #00b4d8;
  --bg-dark: #0b1533;
  --bg-dark-2: #0e1d45;
  --bg-light: #f5f8fd;
  --text-main: #1c2b4a;
  --text-sub: #5a6b8c;
  --white: #ffffff;
  --border: #e3ecf7;
  --shadow: 0 8px 30px rgba(21, 101, 216, 0.12);
  --radius: 14px;
  --font: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: var(--font);
  color: var(--text-main);
  background: var(--bg-light);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

a { text-decoration: none; color: inherit; }
ul, ol { list-style: none; }
img { max-width: 100%; display: block; }
.container { width: min(1160px, 92%); margin: 0 auto; }

/* ============ 顶部导航 ============ */
.nav {
  position: sticky;
  top: 0;
  z-index: 999;
  background: rgba(11, 21, 51, 0.96);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}
.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 68px;
}
.nav-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  color: #fff;
  font-size: 20px;
  font-weight: 700;
  letter-spacing: 0.5px;
}
.nav-logo .logo-icon {
  width: 36px; height: 36px;
  border-radius: 9px;
  background: linear-gradient(135deg, var(--primary-light), var(--accent));
  display: flex; align-items: center; justify-content: center;
  font-weight: 800; font-size: 18px; color: #fff;
  box-shadow: 0 4px 12px rgba(0, 180, 216, 0.4);
}
.nav-menu { display: flex; align-items: center; gap: 6px; }
.nav-menu a {
  color: rgba(255, 255, 255, 0.82);
  font-size: 15px;
  padding: 8px 14px;
  border-radius: 8px;
  transition: all 0.2s;
}
.nav-menu a:hover, .nav-menu a.active { color: #fff; background: rgba(255, 255, 255, 0.1); }
.nav-download-btn {
  background: linear-gradient(135deg, var(--primary-light), var(--accent));
  color: #fff !important;
  font-weight: 600;
  padding: 9px 20px !important;
  border-radius: 999px !important;
  box-shadow: 0 4px 14px rgba(0, 180, 216, 0.35);
}
.nav-toggle { display: none; background: none; border: none; cursor: pointer; padding: 6px; }
.nav-toggle span {
  display: block; width: 24px; height: 2px;
  background: #fff; margin: 5px 0; border-radius: 2px;
  transition: 0.25s;
}

/* ============ Hero ============ */
.hero {
  position: relative;
  background:
    radial-gradient(900px 400px at 85% -10%, rgba(0, 180, 216, 0.25), transparent 60%),
    radial-gradient(700px 380px at 10% 0%, rgba(91, 155, 240, 0.22), transparent 55%),
    linear-gradient(160deg, var(--bg-dark) 0%, var(--bg-dark-2) 55%, #142a5e 100%);
  color: #fff;
  padding: 96px 0 88px;
  overflow: hidden;
}
.hero::after {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(255,255,255,0.035) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,0.035) 1px, transparent 1px);
  background-size: 46px 46px;
  pointer-events: none;
}
.hero-inner { position: relative; z-index: 2; text-align: center; }
.hero-badge {
  display: inline-flex; align-items: center; gap: 8px;
  background: rgba(0, 180, 216, 0.15);
  border: 1px solid rgba(0, 180, 216, 0.4);
  color: #8fe8ff;
  font-size: 13px;
  padding: 6px 16px;
  border-radius: 999px;
  margin-bottom: 24px;
}
.hero h1 {
  font-size: clamp(30px, 4.6vw, 52px);
  font-weight: 800;
  line-height: 1.25;
  letter-spacing: 1px;
  margin-bottom: 18px;
}
.hero h1 .grad {
  background: linear-gradient(90deg, #7cc6ff, #4be1ff);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.hero p.sub {
  font-size: clamp(15px, 2vw, 18px);
  color: rgba(255, 255, 255, 0.78);
  max-width: 720px;
  margin: 0 auto 36px;
}
.hero-actions { display: flex; justify-content: center; gap: 16px; flex-wrap: wrap; }
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 13px 30px;
  border-radius: 999px;
  font-size: 16px;
  font-weight: 600;
  transition: transform 0.2s, box-shadow 0.2s;
  border: none; cursor: pointer;
}
.btn:hover { transform: translateY(-2px); }
.btn-primary {
  background: linear-gradient(135deg, var(--primary-light), var(--accent));
  color: #fff;
  box-shadow: 0 8px 24px rgba(0, 180, 216, 0.4);
}
.btn-ghost {
  background: rgba(255, 255, 255, 0.08);
  color: #fff;
  border: 1px solid rgba(255, 255, 255, 0.25);
}
.hero-stats {
  display: flex; justify-content: center; gap: 48px;
  margin-top: 56px; flex-wrap: wrap;
}
.hero-stats .stat { text-align: center; }
.hero-stats .num {
  font-size: 28px; font-weight: 800;
  background: linear-gradient(90deg, #7cc6ff, #4be1ff);
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.hero-stats .label { font-size: 13px; color: rgba(255, 255, 255, 0.6); margin-top: 2px; }

/* ============ 通用区块 ============ */
.section { padding: 84px 0; }
.section-head { text-align: center; margin-bottom: 52px; }
.section-head .tag {
  display: inline-block;
  color: var(--primary);
  background: rgba(21, 101, 216, 0.08);
  font-size: 13px;
  font-weight: 600;
  padding: 5px 14px;
  border-radius: 999px;
  margin-bottom: 14px;
  letter-spacing: 1px;
}
.section-head h2 { font-size: clamp(24px, 3vw, 34px); font-weight: 800; }
.section-head p { color: var(--text-sub); margin-top: 10px; max-width: 640px; margin-left: auto; margin-right: auto; }

/* 功能卡片 */
.cards { display: grid; grid-template-columns: repeat(4, 1fr); gap: 22px; }
.card {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 30px 24px;
  box-shadow: var(--shadow);
  transition: transform 0.25s, box-shadow 0.25s;
  position: relative;
  overflow: hidden;
}
.card::before {
  content: "";
  position: absolute; top: 0; left: 0; right: 0; height: 4px;
  background: linear-gradient(90deg, var(--primary-light), var(--accent));
  opacity: 0; transition: opacity 0.25s;
}
.card:hover { transform: translateY(-6px); box-shadow: 0 16px 40px rgba(21, 101, 216, 0.18); }
.card:hover::before { opacity: 1; }
.card .icon {
  width: 56px; height: 56px;
  border-radius: 14px;
  background: linear-gradient(135deg, rgba(21, 101, 216, 0.1), rgba(0, 180, 216, 0.12));
  display: flex; align-items: center; justify-content: center;
  font-size: 26px;
  margin-bottom: 18px;
}
.card h3 { font-size: 18px; font-weight: 700; margin-bottom: 10px; }
.card p { font-size: 14px; color: var(--text-sub); }

/* 下载区 */
.download-bg { background: linear-gradient(180deg, var(--bg-dark) 0%, var(--bg-dark-2) 100%); color: #fff; }
.download-bg .section-head p { color: rgba(255, 255, 255, 0.65); }
.download-bg .section-head .tag {
  background: rgba(0, 180, 216, 0.15); color: #8fe8ff;
  border: 1px solid rgba(0, 180, 216, 0.35);
}
.download-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 26px; }
.download-card {
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: var(--radius);
  padding: 36px 32px;
  text-align: center;
  transition: transform 0.25s, border-color 0.25s;
}
.download-card:hover { transform: translateY(-4px); border-color: rgba(0, 180, 216, 0.5); }
.download-card .os-icon { font-size: 44px; margin-bottom: 16px; }
.download-card h3 { font-size: 22px; font-weight: 700; margin-bottom: 8px; }
.download-card .ver {
  font-size: 14px; color: #8fe8ff;
  background: rgba(0, 180, 216, 0.12);
  display: inline-block; padding: 3px 12px; border-radius: 999px;
  margin-bottom: 12px;
}
.download-card p { font-size: 14px; color: rgba(255, 255, 255, 0.65); margin-bottom: 24px; }
.download-meta {
  margin-top: 26px; text-align: center;
  font-size: 13px; color: rgba(255, 255, 255, 0.5);
}
.download-meta a { color: #8fe8ff; }

/* 教程步骤 */
.steps { max-width: 820px; margin: 0 auto; counter-reset: step; }
.step {
  display: flex; gap: 20px;
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px 26px;
  margin-bottom: 16px;
  box-shadow: var(--shadow);
}
.step-num {
  flex-shrink: 0;
  width: 44px; height: 44px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--primary-light), var(--accent));
  color: #fff; font-size: 18px; font-weight: 700;
  display: flex; align-items: center; justify-content: center;
  box-shadow: 0 4px 12px rgba(0, 180, 216, 0.35);
}
.step h4 { font-size: 17px; font-weight: 700; margin-bottom: 6px; }
.step p { font-size: 14.5px; color: var(--text-sub); }
.step code {
  background: #eef4fd; color: var(--primary-dark);
  padding: 2px 8px; border-radius: 5px;
  font-family: Consolas, Monaco, monospace; font-size: 13px;
}

/* FAQ */
.faq-list { max-width: 820px; margin: 0 auto; }
.faq-item {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: 12px;
  margin-bottom: 14px;
  overflow: hidden;
  box-shadow: var(--shadow);
}
.faq-q {
  display: flex; align-items: center; justify-content: space-between;
  padding: 18px 24px; cursor: pointer; font-size: 15.5px; font-weight: 600;
  user-select: none;
}
.faq-q .arrow { transition: transform 0.25s; color: var(--primary); font-size: 14px; }
.faq-item.open .faq-q .arrow { transform: rotate(180deg); }
.faq-a { max-height: 0; overflow: hidden; transition: max-height 0.3s ease; }
.faq-a-inner { padding: 0 24px 20px; font-size: 14.5px; color: var(--text-sub); }

/* 页脚 */
.footer {
  background: var(--bg-dark);
  color: rgba(255, 255, 255, 0.6);
  padding: 44px 0 28px;
  font-size: 14px;
}
.footer-top {
  display: grid; grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 30px; padding-bottom: 32px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}
.footer h5 { color: #fff; font-size: 15px; margin-bottom: 14px; }
.footer-brand p { margin-top: 12px; font-size: 13.5px; }
.footer-links li { margin-bottom: 8px; }
.footer-links a:hover { color: #8fe8ff; }
.footer-bottom {
  padding-top: 24px; text-align: center;
  font-size: 13px;
  display: flex; justify-content: center; gap: 20px; flex-wrap: wrap;
}
.footer-bottom a:hover { color: #8fe8ff; }

/* ============ 子页横幅 ============ */
.page-banner {
  background:
    radial-gradient(700px 300px at 80% -20%, rgba(0, 180, 216, 0.22), transparent 60%),
    linear-gradient(160deg, var(--bg-dark), #142a5e);
  color: #fff;
  padding: 64px 0 56px;
  text-align: center;
}
.page-banner h1 { font-size: clamp(26px, 3.4vw, 38px); font-weight: 800; margin-bottom: 10px; }
.page-banner p { color: rgba(255, 255, 255, 0.7); font-size: 15.5px; max-width: 660px; margin: 0 auto; }
.breadcrumb { margin-top: 16px; font-size: 13px; color: rgba(255, 255, 255, 0.5); }
.breadcrumb a { color: #8fe8ff; }
.breadcrumb a:hover { text-decoration: underline; }

/* 功能详情列表 */
.feature-list { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; }
.feature-item {
  background: var(--white); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 26px 24px;
  display: flex; gap: 16px; box-shadow: var(--shadow);
}
.feature-item .f-icon {
  flex-shrink: 0; width: 46px; height: 46px; border-radius: 12px;
  background: linear-gradient(135deg, rgba(21,101,216,0.1), rgba(0,180,216,0.12));
  display: flex; align-items: center; justify-content: center; font-size: 22px;
}
.feature-item h3 { font-size: 16.5px; font-weight: 700; margin-bottom: 6px; }
.feature-item p { font-size: 14px; color: var(--text-sub); }

/* 关于页 */
.about-block {
  background: var(--white); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 32px;
  box-shadow: var(--shadow); margin-bottom: 24px;
}
.about-block h3 { font-size: 19px; font-weight: 700; margin-bottom: 14px; color: var(--primary-dark); }
.about-block p { font-size: 14.8px; color: var(--text-sub); margin-bottom: 10px; }
.about-block ul { margin-top: 6px; }
.about-block ul li {
  position: relative; padding-left: 22px; margin-bottom: 8px;
  font-size: 14.5px; color: var(--text-sub);
}
.about-block ul li::before {
  content: "✓"; position: absolute; left: 0; color: var(--accent); font-weight: 700;
}
.about-block code {
  background: #eef4fd; color: var(--primary-dark);
  padding: 2px 8px; border-radius: 5px;
  font-family: Consolas, Monaco, monospace; font-size: 13px;
}

/* 表格 */
.table-wrap { overflow-x: auto; box-shadow: var(--shadow); border-radius: var(--radius); border: 1px solid var(--border); }
table { width: 100%; border-collapse: collapse; background: #fff; font-size: 14.5px; }
th, td { padding: 13px 16px; text-align: left; border-bottom: 1px solid var(--border); }
th { background: var(--bg-dark); color: #fff; font-weight: 600; white-space: nowrap; }
tr:hover td { background: #f7fafe; }

/* 提示框 */
.note {
  border-radius: 12px; padding: 16px 20px; margin: 18px 0;
  font-size: 14px; display: flex; gap: 12px; align-items: flex-start;
}
.note-warn { background: #fff7e8; border: 1px solid #ffd591; color: #874d00; }
.note-info { background: #eef7ff; border: 1px solid #a8d5ff; color: #0b4b8a; }
.note .note-icon { font-size: 18px; line-height: 1.4; }

/* ============ 响应式 ============ */
@media (max-width: 960px) {
  .cards { grid-template-columns: 1fr 1fr; }
  .feature-list { grid-template-columns: 1fr; }
  .footer-top { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 640px) {
  .nav-toggle { display: block; }
  .nav-menu {
    position: absolute; top: 68px; left: 0; right: 0;
    background: var(--bg-dark);
    flex-direction: column; align-items: stretch;
    padding: 12px 20px 20px;
    gap: 4px;
    display: none;
    border-bottom: 1px solid rgba(255,255,255,0.1);
  }
  .nav-menu.open { display: flex; }
  .nav-menu a { padding: 12px 14px; }
  .cards, .download-grid, .feature-list { grid-template-columns: 1fr; }
  .section { padding: 60px 0; }
  .hero-stats { gap: 28px; }
  .step { flex-direction: column; gap: 12px; }
  .footer-top { grid-template-columns: 1fr; gap: 24px; }
}