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

:root {
  /* 背景层级（对齐 atmospheric_theme.dart） */
  --bg-1: #0C0E15;   /* surfaceContainerLowest */
  --bg-2: #11131A;   /* surface / surfaceDim */
  --bg-3: #18132B;   /* 背景渐变终点 */
  --surface: #1D1F26;      /* surfaceContainer */
  --surface-2: #282A31;    /* surfaceContainerHigh */
  --surface-3: #373940;    /* surfaceBright / surfaceVariant */

  /* 品牌主色 */
  --primary: #CBBEFF;              /* primary */
  --on-primary: #321587;           /* onPrimary */
  --primary-container: #48319D;    /* primaryContainer */
  --on-primary-container: #CBBEFF; /* onPrimaryContainer */
  --secondary: #EEB1FF;            /* secondary */
  --tertiary: #DCC661;             /* tertiary */

  /* 文字 */
  --text: #E2E2EC;          /* onSurface */
  --text-secondary: #CAC4D4; /* onSurfaceVariant */
  --text-tertiary: #938E9E;  /* outline */
  --border: #484552;         /* outlineVariant */

  /* 渐变与阴影 */
  --gradient-primary: linear-gradient(135deg, #48319D 0%, #614CB8 55%, #B502ED 100%);
  --shadow: 0 6px 24px rgba(0, 0, 0, 0.35);
  --shadow-hover: 0 12px 32px rgba(72, 49, 157, 0.4);
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: 'Manrope', 'Noto Sans SC', sans-serif;
  background: linear-gradient(180deg, var(--bg-1) 0%, var(--bg-2) 50%, var(--bg-3) 100%);
  color: var(--text);
  min-height: 100vh;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  display: flex;
  flex-direction: column;
}

main {
  flex: 1;
}

.container {
  width: 100%;
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 2rem;
}

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

a:hover {
  text-decoration: underline;
}

/* ===== 导航栏 ===== */
.navbar {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(17, 19, 26, 0.9);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}

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

.brand {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font-size: 1.35rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  color: var(--text);
}

.brand-logo {
  height: 32px;
  width: auto;
  display: block;
}

.brand span {
  color: var(--text);
}

.brand-name em {
  font-style: normal;
  color: var(--primary);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 1.3rem;
}

.nav-links a {
  color: var(--text-secondary);
  font-size: 0.95rem;
  font-weight: 500;
  transition: color 0.2s ease;
}

.nav-links a:hover {
  color: var(--primary);
  text-decoration: none;
}

.nav-links a.active {
  color: var(--primary);
  font-weight: 600;
}

.nav-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.5rem;
}

.nav-toggle .bar {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--text);
  margin: 5px 0;
  border-radius: 2px;
  transition: all 0.3s ease;
}

/* ===== 页脚 ===== */
footer {
  text-align: center;
  padding: 2.5rem 0 3rem;
  border-top: 1px solid var(--border);
  color: var(--text-tertiary);
  font-size: 0.85rem;
  margin-top: 3rem;
}

footer .links {
  margin-bottom: 1rem;
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 1.5rem;
}

footer .links a {
  color: var(--text-secondary);
}

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

/* ===== 页头标题区 ===== */
.page-header {
  text-align: center;
  padding: 3.5rem 0 2rem;
}

.page-header h1 {
  font-size: 2rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
  color: var(--text);
}

.page-header p {
  color: var(--text-secondary);
  font-size: 0.95rem;
}

/* ===== Hero ===== */
.hero {
  text-align: center;
  padding: 4.5rem 0 3.5rem;
}

.hero-logo {
  height: 120px;
  width: auto;
  margin-bottom: 1rem;
  filter: drop-shadow(0 8px 24px rgba(0, 0, 0, 0.4));
}

.hero h1 {
  font-size: 3rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  margin-bottom: 0.5rem;
  color: var(--text);
}

.hero h1 span {
  color: var(--primary);
}

.hero .tagline {
  font-size: 0.95rem;
  color: var(--text-secondary);
  letter-spacing: 0.18em;
  margin-bottom: 1.5rem;
}

.hero .desc {
  max-width: 640px;
  margin: 0 auto 2rem;
  color: var(--text-secondary);
  font-size: 1rem;
}

.hero .actions {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
}

/* ===== 按钮 ===== */
.btn {
  display: inline-block;
  background: var(--primary);
  color: var(--on-primary);
  font-weight: 600;
  padding: 0.75rem 2rem;
  border-radius: 999px;
  font-size: 0.95rem;
  transition: all 0.25s ease;
  box-shadow: 0 4px 14px rgba(72, 49, 157, 0.35);
}

.btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 20px rgba(72, 49, 157, 0.5);
  text-decoration: none;
}

.btn-ghost {
  background: transparent;
  color: var(--primary);
  border: 1px solid var(--primary);
  box-shadow: none;
}

.btn-ghost:hover {
  background: rgba(203, 190, 255, 0.08);
  box-shadow: none;
}

/* ===== 区块 ===== */
.section {
  margin-bottom: 2.5rem;
}

.section-title {
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 0.75rem;
}

.section-sub {
  font-size: 0.95rem;
  color: var(--text-secondary);
  margin-bottom: 1.5rem;
}

/* ===== 卡片 ===== */
.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 2rem 2.25rem;
  box-shadow: var(--shadow);
}

.card p {
  color: var(--text-secondary);
  font-size: 0.95rem;
}

/* ===== 功能网格 ===== */
.features {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 1.5rem;
}

.feature-item {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 1.75rem 1.5rem;
  text-align: center;
  box-shadow: var(--shadow);
  transition: all 0.3s ease;
  display: block;
  color: inherit;
}

.feature-item:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-hover);
  border-color: var(--primary);
  text-decoration: none;
}

.feature-icon {
  font-size: 2.2rem;
  margin-bottom: 0.9rem;
}

.feature-title {
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 0.5rem;
}

.feature-desc {
  font-size: 0.88rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

/* ===== 品牌渐变重点卡片 ===== */
.primary-card {
  background: var(--gradient-primary);
  color: #FFFFFF;
  border-radius: 16px;
  padding: 2.25rem 2.5rem;
  text-align: center;
  box-shadow: 0 12px 32px rgba(72, 49, 157, 0.4);
}

.primary-card h2 {
  font-size: 1.5rem;
  font-weight: 600;
  margin-bottom: 0.75rem;
  color: #FFFFFF;
}

.primary-card p {
  font-size: 0.95rem;
  opacity: 0.92;
  margin-bottom: 1.5rem;
  color: #FFFFFF;
}

.btn-light {
  display: inline-block;
  background: #FFFFFF;
  color: var(--primary-container);
  font-weight: 600;
  padding: 0.75rem 2.25rem;
  border-radius: 999px;
  font-size: 0.95rem;
  transition: all 0.25s ease;
  box-shadow: 0 4px 14px rgba(0, 0, 0, 0.25);
}

.btn-light:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 20px rgba(0, 0, 0, 0.35);
  text-decoration: none;
}

/* ===== 联系列表 ===== */
.contact-list {
  list-style: none;
  margin-top: 0.5rem;
}

.contact-list li {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.65rem 0;
  color: var(--text-secondary);
  font-size: 0.95rem;
}

.contact-list .label {
  color: var(--text-tertiary);
  flex-shrink: 0;
  min-width: 4em;
}

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

/* ===== 协议链接 ===== */
.legal-links {
  display: flex;
  flex-wrap: wrap;
  gap: 1.5rem;
  margin-top: 1rem;
}

.legal-links a {
  color: var(--primary);
  font-size: 0.95rem;
}

/* ===== 留言表单 ===== */
.feedback-form {
  margin-top: 1.25rem;
}

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}

.form-group {
  margin-bottom: 1rem;
}

.form-group label {
  display: block;
  color: var(--text-secondary);
  font-size: 0.85rem;
  margin-bottom: 0.4rem;
}

.form-group input,
.form-group textarea {
  width: 100%;
  padding: 0.65rem 0.85rem;
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: 10px;
  color: var(--text);
  font-family: inherit;
  font-size: 0.95rem;
  transition: border-color 0.2s ease;
  resize: vertical;
}

.form-group input:focus,
.form-group textarea:focus {
  outline: none;
  border-color: var(--primary);
}

.form-hint {
  margin-top: 0.75rem;
  font-size: 0.88rem;
  color: var(--text-tertiary);
}

.form-hint.success {
  color: #8BE8B0;
}

.form-hint.error {
  color: #FFB4AB;
}

@media (max-width: 768px) {
  .form-row {
    grid-template-columns: 1fr;
  }
}

/* ===== 新闻列表 ===== */
.news-list {
  list-style: none;
  margin-top: 0.5rem;
}

.news-item {
  padding: 1rem 0;
  border-bottom: 1px solid var(--border);
}

.news-item:last-child {
  border-bottom: none;
}

.news-date {
  display: inline-block;
  color: var(--text-tertiary);
  font-size: 0.8rem;
  margin-bottom: 0.25rem;
  letter-spacing: 0.02em;
}

.news-title {
  display: block;
  font-size: 1.02rem;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 0.25rem;
}

.news-title:hover {
  color: var(--primary);
  text-decoration: none;
}

.news-desc {
  font-size: 0.88rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

/* ===== 常见问题（details 折叠） ===== */
.faq-list {
  margin-top: 0.5rem;
}

.faq-item {
  border: 1px solid var(--border);
  border-radius: 12px;
  margin-bottom: 0.85rem;
  background: var(--surface-2);
  padding: 0 1.1rem;
}

.faq-item summary {
  list-style: none;
  cursor: pointer;
  padding: 0.9rem 0;
  font-size: 0.98rem;
  font-weight: 600;
  color: var(--text);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.faq-item summary::-webkit-details-marker {
  display: none;
}

.faq-item summary::after {
  content: '+';
  font-size: 1.3rem;
  font-weight: 400;
  color: var(--primary);
  transition: transform 0.2s ease;
  flex-shrink: 0;
}

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

.faq-item > p {
  padding: 0 0 1rem;
  font-size: 0.92rem;
  color: var(--text-secondary);
  line-height: 1.7;
}

.faq-more {
  margin-top: 1.5rem;
  font-size: 0.95rem;
  color: var(--text-secondary);
}

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

/* ===== 正文内容排版 ===== */
.prose h3 {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--text);
  margin: 1.25rem 0 0.5rem;
}

.prose h3:first-child {
  margin-top: 0;
}

.prose p {
  color: var(--text-secondary);
  font-size: 0.95rem;
  margin-bottom: 0.75rem;
}

/* ===== 响应式 ===== */
@media (max-width: 768px) {
  .container {
    padding: 0 1.25rem;
  }

  .nav-toggle {
    display: block;
  }

  .nav-links {
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    background: var(--bg-2);
    border-bottom: 1px solid var(--border);
    box-shadow: var(--shadow);
    padding: 0.5rem 1.25rem;
    display: none;
  }

  .nav-links.open {
    display: flex;
  }

  .nav-links a {
    padding: 0.8rem 0;
    border-bottom: 1px solid var(--border);
  }

  .nav-links a:last-child {
    border-bottom: none;
  }

  .hero h1 {
    font-size: 2rem;
  }

  .features {
    grid-template-columns: 1fr;
  }

  .primary-card {
    padding: 2rem 1.5rem;
  }

  .card {
    padding: 1.5rem 1.25rem;
  }

  .page-header h1 {
    font-size: 1.6rem;
  }
}