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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    "Helvetica Neue", Arial, "Noto Sans SC", sans-serif;
  line-height: 1.8;
  color: #333;
  background: #f5f7fa;
}

.container {
  max-width: 860px;
  margin: 0 auto;
  padding: 40px 24px;
}

/* 首页卡片列表 */
.page-header {
  text-align: center;
  margin-bottom: 48px;
}

.page-header h1 {
  font-size: 28px;
  font-weight: 600;
  color: #1a1a1a;
  margin-bottom: 8px;
}

.page-header p {
  font-size: 15px;
  color: #888;
}

.card-list {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.card {
  background: #fff;
  border-radius: 12px;
  padding: 24px 28px;
  text-decoration: none;
  color: inherit;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.06);
  transition: box-shadow 0.2s, transform 0.2s;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.card:hover {
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
  transform: translateY(-2px);
}

.card-title {
  font-size: 17px;
  font-weight: 500;
  color: #1a1a1a;
}

.card-desc {
  font-size: 13px;
  color: #999;
  margin-top: 4px;
}

.card-arrow {
  font-size: 20px;
  color: #ccc;
  flex-shrink: 0;
  margin-left: 16px;
}

/* 协议内容页 */
.doc-header {
  text-align: center;
  margin-bottom: 40px;
  padding-bottom: 24px;
  border-bottom: 1px solid #eee;
}

.doc-header h1 {
  font-size: 26px;
  font-weight: 600;
  color: #1a1a1a;
  margin-bottom: 8px;
}

.doc-header .update-date {
  font-size: 13px;
  color: #aaa;
}

.doc-body {
  background: #fff;
  border-radius: 12px;
  padding: 40px 36px;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.06);
}

.doc-body h2 {
  font-size: 20px;
  font-weight: 600;
  color: #1a1a1a;
  margin: 32px 0 12px;
}

.doc-body h2:first-child {
  margin-top: 0;
}

.doc-body h3 {
  font-size: 16px;
  font-weight: 500;
  color: #333;
  margin: 20px 0 8px;
}

.doc-body p {
  margin-bottom: 12px;
  font-size: 15px;
  text-align: justify;
}

.doc-body ul,
.doc-body ol {
  margin: 8px 0 16px 20px;
  font-size: 15px;
}

.doc-body li {
  margin-bottom: 6px;
}

.back-link {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  color: #666;
  text-decoration: none;
  font-size: 14px;
  margin-bottom: 24px;
  transition: color 0.2s;
}

.back-link:hover {
  color: #333;
}

/* 404 */
.not-found {
  text-align: center;
  padding: 80px 24px;
}

.not-found h1 {
  font-size: 72px;
  font-weight: 700;
  color: #ddd;
}

.not-found p {
  font-size: 16px;
  color: #999;
  margin: 12px 0 24px;
}

.not-found a {
  color: #4a90d9;
  text-decoration: none;
}

.not-found a:hover {
  text-decoration: underline;
}

@media (max-width: 640px) {
  .container {
    padding: 24px 16px;
  }

  .doc-body {
    padding: 24px 20px;
  }
}