/* ====================================================
   style.css — SafeW 加密聊天软件 全局样式表
   原创手写 · 去 AI 味 · 2026
   ==================================================== */

/* ---------- 重置 & 基础 ---------- */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: system-ui, -apple-system, 'Segoe UI', Roboto, 'Helvetica Neue', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  background: #f7f9fc;
  color: #1a1e2b;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

a {
  text-decoration: none;
  color: inherit;
}

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

/* ---------- 容器 ---------- */
.container {
  max-width: 1260px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ---------- 头部 ---------- */
.header {
  background: #ffffff;
  box-shadow: 0 2px 12px rgba(0, 0, 0, 0.03);
  padding: 14px 0;
  border-bottom: 1px solid #eaedf2;
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(6px);
  -webkit-backdrop-filter: blur(6px);
  background: rgba(255, 255, 255, 0.92);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
}

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

.logo-area img {
  height: 42px;
  width: auto;
  display: block;
}

.logo-text {
  font-size: 1.5rem;
  font-weight: 600;
  letter-spacing: -0.3px;
  color: #0b1c3a;
}

.logo-text span {
  color: #2a7de1;
}

/* ---------- 导航 ---------- */
.nav {
  display: flex;
  align-items: center;
  gap: 28px;
  font-weight: 500;
  font-size: 1.15rem;
  flex-wrap: wrap;
}

.nav a {
  padding: 6px 0;
  border-bottom: 2.5px solid transparent;
  transition: border-color 0.2s, color 0.2s;
  color: #1e293b;
  display: inline-flex;
  align-items: center;
  gap: 5px;
}

.nav a i {
  font-size: 0.9rem;
  color: #3b4a5e;
}

.nav a:hover,
.nav a.active {
  border-bottom-color: #2a7de1;
  color: #0b1c3a;
}

.nav a.active i {
  color: #2a7de1;
}

/* ---------- 响应式头部 ---------- */
@media (max-width: 768px) {
  .header {
    padding: 10px 0;
  }
  .header-inner {
    flex-direction: column;
    align-items: stretch;
    gap: 8px;
  }
  .logo-area {
    justify-content: center;
  }
  .nav {
    justify-content: center;
    gap: 14px 18px;
    font-size: 1rem;
  }
  .nav a {
    padding: 4px 0;
  }
}

@media (max-width: 480px) {
  .nav {
    gap: 10px 14px;
    font-size: 0.9rem;
  }
  .logo-text {
    font-size: 1.2rem;
  }
  .logo-area img {
    height: 34px;
  }
}

/* ---------- 按钮 ---------- */
.btn {
  display: inline-block;
  background: #2a7de1;
  color: #fff;
  padding: 12px 34px;
  border-radius: 60px;
  font-weight: 500;
  font-size: 1rem;
  border: none;
  cursor: pointer;
  transition: background 0.2s, transform 0.15s;
  box-shadow: 0 4px 12px rgba(42, 125, 225, 0.25);
  text-align: center;
}

.btn:hover {
  background: #1c62b8;
  transform: scale(1.01);
}

.btn:active {
  transform: scale(0.97);
}

.btn-outline {
  background: transparent;
  color: #2a7de1;
  border: 1.5px solid #2a7de1;
  box-shadow: none;
}

.btn-outline:hover {
  background: #eef5fe;
  transform: scale(1.01);
}

.btn-sm {
  background: #2a7de1;
  color: #fff;
  border: none;
  padding: 8px 28px;
  border-radius: 60px;
  font-weight: 500;
  font-size: 0.95rem;
  cursor: pointer;
  transition: background 0.2s;
  display: inline-block;
  text-align: center;
}

.btn-sm:hover {
  background: #1c62b8;
}

.btn-sm-outline {
  background: transparent;
  color: #2a7de1;
  border: 1.5px solid #2a7de1;
}

.btn-sm-outline:hover {
  background: #eef5fe;
}

/* ---------- 通用标题 ---------- */
.section-title {
  font-size: 2.2rem;
  font-weight: 600;
  letter-spacing: -0.5px;
  margin-bottom: 12px;
  color: #0b1c3a;
}

.section-sub {
  font-size: 1.1rem;
  color: #3f4d65;
  max-width: 700px;
  margin-bottom: 36px;
}

/* ---------- 卡片网格 ---------- */
.grid-2col {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 30px;
}

.card {
  background: #fff;
  padding: 28px 24px 30px;
  border-radius: 24px;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.02);
  border: 1px solid #eef2f7;
  transition: border-color 0.2s, box-shadow 0.25s;
}

.card:hover {
  box-shadow: 0 12px 32px rgba(0, 20, 60, 0.06);
  border-color: #d0dbe8;
}

.card i {
  font-size: 2.4rem;
  color: #2a7de1;
  margin-bottom: 14px;
  display: inline-block;
}

.card h3 {
  font-size: 1.3rem;
  font-weight: 600;
  margin-bottom: 8px;
  color: #0b1c3a;
}

.card p {
  color: #2d3a4f;
  font-size: 0.98rem;
  line-height: 1.7;
}

/* ---------- 文章网格 (首页摘要) ---------- */
.article-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
  gap: 24px;
}

.article-item {
  background: #fff;
  border-radius: 20px;
  padding: 20px 20px 22px;
  border: 1px solid #eaeef4;
  transition: border-color 0.2s, box-shadow 0.2s;
  display: block;
  color: inherit;
}

.article-item:hover {
  border-color: #bccde0;
  box-shadow: 0 6px 20px rgba(0, 20, 40, 0.04);
}

.article-item h4 {
  font-size: 1.15rem;
  font-weight: 600;
  margin-bottom: 4px;
  color: #0b1c3a;
}

.article-item .meta {
  color: #63758b;
  font-size: 0.82rem;
  display: flex;
  align-items: center;
  gap: 12px;
  margin: 8px 0 10px;
}

.article-item .meta i {
  color: #2a7de1;
  font-size: 0.8rem;
}

.article-item p {
  color: #2d3f5a;
  font-size: 0.95rem;
  line-height: 1.6;
  margin: 0;
}

/* ---------- 辅助工具 ---------- */
.text-center {
  text-align: center;
}

.flex-center {
  display: flex;
  align-items: center;
  gap: 14px;
  flex-wrap: wrap;
}

.mt-16 {
  margin-top: 16px;
}
.mt-32 {
  margin-top: 32px;
}
.mb-16 {
  margin-bottom: 16px;
}

/* ---------- 平台标签 (下载页用) ---------- */
.platform-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: #eaf1fd;
  padding: 6px 20px;
  border-radius: 40px;
  font-weight: 500;
  font-size: 0.9rem;
  color: #1a3c73;
}

/* ---------- Footer ---------- */
.footer {
  background: #0b1c3a;
  color: #cbd5e1;
  padding: 40px 0 20px;
  margin-top: 60px;
}

.footer .container {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 28px;
}

.footer-col {
  flex: 1 1 180px;
}

.footer-col h4 {
  color: #fff;
  font-weight: 500;
  margin-bottom: 14px;
  font-size: 1.05rem;
}

.footer-col p,
.footer-col a {
  font-size: 0.93rem;
  line-height: 1.9;
  color: #b3c2d9;
}

.footer-col a:hover {
  color: #fff;
}

.footer-bottom {
  border-top: 1px solid #1f3455;
  margin-top: 28px;
  padding-top: 18px;
  text-align: center;
  font-size: 0.9rem;
  color: #8b9bb5;
}

/* ---------- 响应式 Footer ---------- */
@media (max-width: 640px) {
  .footer .container {
    flex-direction: column;
    gap: 20px;
  }
  .footer-col {
    flex: 1 1 100%;
  }
}

/* ---------- 工具：隐藏结构化数据 ---------- */
.structured-data {
  display: none;
}

/* ---------- 小屏微调 ---------- */
@media (max-width: 600px) {
  .section-title {
    font-size: 1.7rem;
  }
  .grid-2col {
    grid-template-columns: 1fr;
  }
  .article-grid {
    grid-template-columns: 1fr;
  }
  .card {
    padding: 22px 18px;
  }
}

/* ---------- 文章页面通用 (article-*.html 共用) ---------- */
.article-container {
  max-width: 820px;
  margin: 0 auto;
  padding: 20px 0 40px;
}

.article-header {
  margin-bottom: 28px;
}

.article-header h1 {
  font-size: 2.2rem;
  font-weight: 700;
  color: #0b1c3a;
  line-height: 1.3;
}

.article-meta {
  color: #5a6f89;
  font-size: 0.95rem;
  display: flex;
  align-items: center;
  gap: 18px;
  flex-wrap: wrap;
  margin: 12px 0 8px;
}

.article-meta i {
  margin-right: 4px;
}

.article-body {
  font-size: 1.05rem;
  line-height: 1.8;
  color: #1a2a3f;
}

.article-body h2 {
  font-size: 1.6rem;
  font-weight: 600;
  margin: 32px 0 12px;
  color: #0b1c3a;
}

.article-body h3 {
  font-size: 1.25rem;
  font-weight: 600;
  margin: 24px 0 10px;
  color: #0b1c3a;
}

.article-body p {
  margin-bottom: 16px;
}

.article-body ul {
  padding-left: 24px;
  margin-bottom: 16px;
}

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

.article-body img {
  max-width: 100%;
  border-radius: 16px;
  margin: 20px 0;
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.06);
}

.article-body .highlight-box {
  background: #f0f5fe;
  border-left: 4px solid #2a7de1;
  padding: 16px 22px;
  border-radius: 12px;
  margin: 20px 0;
}

/* ---------- 相关文章 (文章页底部) ---------- */
.related-articles {
  margin-top: 48px;
  padding-top: 28px;
  border-top: 1px solid #eef2f7;
}

.related-articles h4 {
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: 16px;
  color: #0b1c3a;
}

.related-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 16px;
}

.related-grid a {
  background: #f8faff;
  padding: 14px 18px;
  border-radius: 16px;
  border: 1px solid #eef2f7;
  color: #0b1c3a;
  font-weight: 500;
  transition: background 0.2s, border-color 0.2s;
  display: block;
}

.related-grid a:hover {
  background: #eef5fe;
  border-color: #c5d8ee;
}

/* ---------- 文章响应式 ---------- */
@media (max-width: 640px) {
  .article-header h1 {
    font-size: 1.7rem;
  }
  .article-body {
    font-size: 0.98rem;
  }
  .article-body h2 {
    font-size: 1.3rem;
  }
  .related-grid {
    grid-template-columns: 1fr;
  }
}