/* 案同学官网 - 简约 / 正式 / 蓝色系 */

:root {
  --primary: #2563eb;
  --primary-dark: #1d4ed8;
  --bg: #ffffff;
  --bg-alt: #f5f8ff;
  --text: #1f2937;
  --text-secondary: #4b5563;
  --border: #e5edfb;
}

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

html {
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB",
    "Microsoft YaHei", "Segoe UI", Roboto, sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.7;
  font-size: 16px;
}

.container {
  max-width: 960px;
  margin: 0 auto;
  padding: 0 20px;
}

/* 顶部 */
.site-header {
  border-bottom: 1px solid var(--border);
  background: var(--bg);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 8px;
  padding-top: 14px;
  padding-bottom: 14px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
}

.brand-mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 34px;
  height: 34px;
  border-radius: 9px;
  background: var(--primary);
  color: #fff;
  font-size: 18px;
  font-weight: 600;
}

.brand-name {
  font-size: 20px;
  font-weight: 700;
  letter-spacing: 1px;
}

.brand-tagline {
  color: var(--text-secondary);
  font-size: 14px;
}

/* Hero */
.hero {
  background: linear-gradient(180deg, #eef4ff 0%, var(--bg) 100%);
  padding: 72px 0 56px;
  text-align: center;
}

.hero h1 {
  font-size: 32px;
  font-weight: 700;
  line-height: 1.4;
  color: var(--text);
}

.hero-sub {
  margin-top: 14px;
  color: var(--primary);
  font-size: 15px;
  letter-spacing: 2px;
}

/* 区块 */
.section {
  padding: 56px 0;
}

.section-alt {
  background: var(--bg-alt);
}

.section-title {
  font-size: 24px;
  font-weight: 700;
  text-align: center;
  margin-bottom: 28px;
}

.sub-title {
  font-size: 19px;
  font-weight: 600;
  text-align: center;
  color: var(--primary-dark);
  margin-bottom: 12px;
}

.lead {
  color: var(--text-secondary);
  font-size: 16px;
  max-width: 720px;
  margin: 0 auto 12px;
  text-align: center;
}

/* 卡片 */
.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(210px, 1fr));
  gap: 16px;
  margin-top: 8px;
}

.card {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 22px 20px;
}

.card h3 {
  font-size: 17px;
  font-weight: 600;
  color: var(--primary-dark);
  margin-bottom: 8px;
}

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

/* 底部 */
.site-footer {
  border-top: 1px solid var(--border);
  background: var(--bg);
  padding: 28px 0;
}

.footer-inner {
  display: flex;
  align-items: center;
  justify-content: center;
  flex-wrap: wrap;
  gap: 8px 20px;
  font-size: 14px;
  color: var(--text-secondary);
}

.footer-brand {
  font-weight: 600;
  color: var(--text);
}

.footer-inner a {
  color: var(--text-secondary);
  text-decoration: none;
}

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

/* 移动端 */
@media (max-width: 640px) {
  .hero {
    padding: 48px 0 40px;
  }

  .hero h1 {
    font-size: 24px;
  }

  .section {
    padding: 44px 0;
  }

  .header-inner {
    justify-content: center;
    text-align: center;
  }
}