/* ===== 全站基础样式 ===== */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  --primary: #ffb800;
  --primary-dark: #f59e0b;
  --secondary: #1f2937;
  --accent: #fbbf24;
  --bg-light: #fffbeb;
  --bg-white: #ffffff;
  --text-main: #111827;
  --text-sub: #4b5563;
  --border: #e5e7eb;
  --shadow: 0 8px 24px rgba(0, 0, 0, 0.08);
  --shadow-hover: 0 16px 40px rgba(0, 0, 0, 0.12);
  --radius: 12px;
  --transition: all 0.3s ease;
}

html,
body {
  font-family: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  color: var(--text-main);
  background: var(--bg-light);
  line-height: 1.7;
  scroll-behavior: smooth;
}

a {
  color: inherit;
  text-decoration: none;
  transition: var(--transition);
}

img {
  max-width: 100%;
  display: block;
}

ul,
ol {
  list-style: none;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ===== 导航栏 ===== */
.navbar {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: saturate(180%) blur(14px);
  border-bottom: 1px solid var(--border);
}

.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 18px;
  color: var(--secondary);
}

.nav-logo img {
  width: 36px;
  height: 36px;
  border-radius: 8px;
  object-fit: cover;
}

.nav-links {
  display: flex;
  gap: 8px;
}

.nav-links a {
  padding: 8px 16px;
  border-radius: 8px;
  font-weight: 500;
  color: var(--text-sub);
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--primary-dark);
  background: var(--bg-light);
}

.nav-toggle {
  display: none;
  background: none;
  border: 0;
  font-size: 24px;
  cursor: pointer;
  color: var(--secondary);
}

/* ===== 按钮 ===== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  padding: 12px 28px;
  font-weight: 600;
  border-radius: 999px;
  border: 0;
  cursor: pointer;
  transition: var(--transition);
  font-size: 15px;
}

.btn-primary {
  background: linear-gradient(135deg, var(--primary), var(--primary-dark));
  color: #1f2937;
  box-shadow: 0 6px 18px rgba(245, 158, 11, 0.35);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 10px 24px rgba(245, 158, 11, 0.45);
}

.btn-outline {
  background: transparent;
  border: 2px solid var(--primary);
  color: var(--primary-dark);
}

.btn-outline:hover {
  background: var(--primary);
  color: #1f2937;
}

.btn-large {
  padding: 16px 40px;
  font-size: 17px;
}

/* ===== 首页首屏 ===== */
.hero {
  position: relative;
  padding: 80px 0 100px;
  background:
    radial-gradient(1200px 600px at 80% -20%, rgba(251, 191, 36, 0.35), transparent 60%),
    radial-gradient(800px 400px at 10% 10%, rgba(255, 184, 0, 0.25), transparent 60%),
    var(--bg-light);
  overflow: hidden;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.1fr 1fr;
  gap: 60px;
  align-items: center;
}

.hero-tag {
  display: inline-block;
  padding: 6px 14px;
  background: rgba(245, 158, 11, 0.12);
  color: var(--primary-dark);
  border-radius: 999px;
  font-weight: 600;
  font-size: 13px;
  margin-bottom: 18px;
}

.hero-title {
  font-size: 48px;
  font-weight: 800;
  line-height: 1.2;
  margin-bottom: 18px;
  background: linear-gradient(135deg, #1f2937 30%, #f59e0b 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.hero-desc {
  font-size: 17px;
  color: var(--text-sub);
  margin-bottom: 32px;
  max-width: 540px;
}

.hero-actions {
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
}

.hero-visual {
  position: relative;
  display: flex;
  justify-content: center;
  align-items: center;
}

.hero-visual img {
  width: 100%;
  max-width: 480px;
  border-radius: 24px;
  box-shadow: var(--shadow-hover);
  animation: floatY 4s ease-in-out infinite;
}

@keyframes floatY {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-12px); }
}

/* ===== 通用区块 ===== */
.section {
  padding: 80px 0;
}

.section-title {
  text-align: center;
  font-size: 34px;
  font-weight: 800;
  margin-bottom: 12px;
}

.section-sub {
  text-align: center;
  color: var(--text-sub);
  margin-bottom: 48px;
  font-size: 16px;
}

/* ===== 功能特性卡片 ===== */
.features {
  background: var(--bg-white);
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 24px;
}

.feature-card {
  padding: 28px;
  background: var(--bg-white);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  transition: var(--transition);
}

.feature-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-hover);
  border-color: var(--primary);
}

.feature-icon {
  width: 56px;
  height: 56px;
  border-radius: 14px;
  background: linear-gradient(135deg, var(--primary), var(--primary-dark));
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 26px;
  color: #fff;
  margin-bottom: 16px;
}

.feature-card h3 {
  font-size: 18px;
  margin-bottom: 8px;
}

.feature-card p {
  color: var(--text-sub);
  font-size: 14px;
}

/* ===== 安装步骤 ===== */
.steps {
  background: var(--bg-light);
}

.steps-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 24px;
}

.step-card {
  background: var(--bg-white);
  border-radius: var(--radius);
  padding: 28px 24px;
  position: relative;
  box-shadow: var(--shadow);
  border-top: 4px solid var(--primary);
}

.step-num {
  position: absolute;
  top: -18px;
  left: 24px;
  width: 38px;
  height: 38px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--primary), var(--primary-dark));
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
  font-size: 16px;
  box-shadow: 0 4px 12px rgba(245, 158, 11, 0.35);
}

.step-card h4 {
  font-size: 17px;
  margin: 12px 0 8px;
  color: var(--secondary);
}

.step-card p {
  color: var(--text-sub);
  font-size: 14px;
}

.step-platform {
  display: inline-block;
  margin-top: 10px;
  padding: 3px 10px;
  background: var(--bg-light);
  color: var(--primary-dark);
  border-radius: 999px;
  font-size: 12px;
  font-weight: 600;
}

/* ===== 系统要求 ===== */
.requirements {
  background: var(--bg-white);
}

.req-tabs {
  display: flex;
  justify-content: center;
  gap: 8px;
  margin-bottom: 32px;
  flex-wrap: wrap;
}

.req-tab {
  padding: 8px 20px;
  border-radius: 999px;
  border: 2px solid var(--border);
  background: var(--bg-white);
  font-weight: 600;
  cursor: pointer;
  color: var(--text-sub);
  transition: var(--transition);
}

.req-tab.active {
  background: var(--primary);
  border-color: var(--primary);
  color: var(--secondary);
}

.req-panel {
  display: none;
  background: var(--bg-light);
  border-radius: var(--radius);
  padding: 32px;
  box-shadow: var(--shadow);
  max-width: 760px;
  margin: 0 auto;
}

.req-panel.active {
  display: block;
  animation: fadeIn 0.4s ease;
}

.req-panel h4 {
  font-size: 22px;
  margin-bottom: 16px;
  color: var(--secondary);
  display: flex;
  align-items: center;
  gap: 8px;
}

.req-list {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 12px 28px;
}

.req-list li {
  padding: 10px 0;
  border-bottom: 1px dashed var(--border);
  color: var(--text-sub);
  font-size: 14px;
}

.req-list li strong {
  color: var(--text-main);
  margin-right: 6px;
}

/* ===== 常见问题 ===== */
.faq {
  background: var(--bg-light);
}

.faq-list {
  max-width: 820px;
  margin: 0 auto;
  display: grid;
  gap: 14px;
}

.faq-item {
  background: var(--bg-white);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  overflow: hidden;
}

.faq-q {
  width: 100%;
  text-align: left;
  background: none;
  border: 0;
  padding: 18px 22px;
  font-size: 16px;
  font-weight: 600;
  color: var(--secondary);
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.faq-q::after {
  content: "+";
  font-size: 22px;
  color: var(--primary-dark);
  transition: transform 0.3s ease;
}

.faq-item.open .faq-q::after {
  transform: rotate(45deg);
}

.faq-a {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.35s ease;
  color: var(--text-sub);
  font-size: 14px;
}

.faq-item.open .faq-a {
  max-height: 240px;
}

.faq-a-inner {
  padding: 0 22px 18px;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(6px); }
  to { opacity: 1; transform: translateY(0); }
}

/* ===== 下载页 ===== */
.download-hero {
  padding: 64px 0 32px;
  background:
    radial-gradient(900px 400px at 50% 0%, rgba(251, 191, 36, 0.3), transparent 60%),
    var(--bg-light);
  text-align: center;
}

.download-hero h1 {
  font-size: 40px;
  font-weight: 800;
  margin-bottom: 12px;
  background: linear-gradient(135deg, #1f2937, #f59e0b);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.download-hero p {
  color: var(--text-sub);
  font-size: 16px;
  max-width: 640px;
  margin: 0 auto;
}

.source-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 28px;
  padding: 48px 0 80px;
}

.source-card {
  background: var(--bg-white);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow);
  display: flex;
  flex-direction: column;
  transition: var(--transition);
  border: 1px solid var(--border);
}

.source-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-hover);
  border-color: var(--primary);
}

.source-thumb {
  width: 100%;
  aspect-ratio: 16 / 10;
  object-fit: cover;
  background: var(--bg-light);
}

.source-body {
  padding: 22px 22px 24px;
  display: flex;
  flex-direction: column;
  flex: 1;
}

.source-badge {
  display: inline-block;
  align-self: flex-start;
  padding: 4px 12px;
  background: rgba(245, 158, 11, 0.15);
  color: var(--primary-dark);
  border-radius: 999px;
  font-size: 12px;
  font-weight: 700;
  margin-bottom: 10px;
}

.source-card h3 {
  font-size: 20px;
  margin-bottom: 8px;
  color: var(--secondary);
}

.source-card p {
  color: var(--text-sub);
  font-size: 14px;
  margin-bottom: 18px;
  flex: 1;
}

.source-meta {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 12px;
  color: var(--text-sub);
  margin-bottom: 14px;
  padding-top: 12px;
  border-top: 1px dashed var(--border);
}

.source-meta span strong {
  color: var(--secondary);
}

/* ===== 404 ===== */
.error-page {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  padding: 40px 20px;
  text-align: center;
  background:
    radial-gradient(900px 500px at 50% 20%, rgba(251, 191, 36, 0.25), transparent 60%),
    var(--bg-light);
}

.error-404 {
  font-size: 140px;
  font-weight: 900;
  line-height: 1;
  background: linear-gradient(135deg, #f59e0b, #fbbf24);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  margin-bottom: 8px;
}

.error-page h1 {
  font-size: 30px;
  margin-bottom: 12px;
  color: var(--secondary);
}

.error-page p {
  color: var(--text-sub);
  max-width: 480px;
  margin-bottom: 28px;
}

.error-page .actions {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  justify-content: center;
}

/* ===== 页脚 ===== */
.footer {
  background: var(--secondary);
  color: #d1d5db;
  padding: 36px 0;
  text-align: center;
  font-size: 14px;
}

.footer a {
  color: var(--primary);
}

.footer p {
  margin: 4px 0;
}

/* ===== 响应式 ===== */
@media (max-width: 900px) {
  .hero-grid { grid-template-columns: 1fr; gap: 40px; text-align: center; }
  .hero-actions { justify-content: center; }
  .hero-desc { margin-left: auto; margin-right: auto; }
  .hero-title { font-size: 38px; }
  .section { padding: 60px 0; }
  .section-title { font-size: 28px; }
  .download-hero h1 { font-size: 30px; }
  .error-404 { font-size: 100px; }
}

@media (max-width: 640px) {
  .nav-links {
    display: none;
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    flex-direction: column;
    background: #fff;
    padding: 12px;
    box-shadow: var(--shadow);
    border-bottom: 1px solid var(--border);
  }
  .nav-links.open { display: flex; }
  .nav-toggle { display: block; }
  .hero-title { font-size: 32px; }
  .container { padding: 0 16px; }
  .req-panel { padding: 22px; }
}