:root {
  --nav-primary: #1e3a5f;
  --nav-primary-light: #e8eef5;
  --nav-accent: #e07a2f;
  --nav-bg: #f5f7fa;
  --nav-card-bg: #fff;
  --nav-text: #1f2937;
  --nav-text-2: #6b7280;
  --nav-text-3: #9ca3af;
  --nav-border: #e5e7eb;
  --nav-radius: 10px;
  --nav-shadow: 0 1px 3px rgba(0,0,0,.06);
}

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

html { scroll-behavior: smooth; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  background: var(--nav-bg);
  color: var(--nav-text);
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
}

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

/* ========== Header ========== */
.nav-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: #fff;
  border-bottom: 1px solid var(--nav-border);
  box-shadow: 0 1px 4px rgba(0,0,0,.04);
}

.nav-header-inner {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 24px;
  height: 60px;
  display: flex;
  align-items: center;
  gap: 20px;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-shrink: 0;
  font-weight: 700;
  color: var(--nav-primary);
}

.nav-logo-img {
  width: 28px;
  height: 28px;
}

.nav-logo-text { font-size: 18px; letter-spacing: -.3px; }

.nav-logo-sep { color: var(--nav-border); font-weight: 300; }

.nav-logo-sub { font-size: 14px; color: var(--nav-text-2); font-weight: 500; }

.nav-search {
  flex: 1;
  max-width: 420px;
  position: relative;
}

.nav-search input {
  width: 100%;
  height: 38px;
  padding: 0 14px 0 38px;
  border: 1.5px solid var(--nav-border);
  border-radius: 8px;
  font-size: 14px;
  background: var(--nav-bg);
  color: var(--nav-text);
  outline: none;
  transition: border-color .2s;
}

.nav-search input:focus { border-color: var(--nav-primary); background: #fff; }

.nav-search input::placeholder { color: var(--nav-text-3); }

.nav-search-icon {
  position: absolute;
  left: 11px;
  top: 50%;
  transform: translateY(-50%);
  width: 16px;
  height: 16px;
  color: var(--nav-text-3);
  pointer-events: none;
}

.nav-header-btn {
  padding: 7px 18px;
  background: var(--nav-primary);
  color: #fff;
  border-radius: 8px;
  font-size: 13px;
  font-weight: 600;
  white-space: nowrap;
  transition: background .2s;
  flex-shrink: 0;
}

.nav-header-btn:hover { background: var(--nav-primary); filter: brightness(1.1); }

/* ========== Tabs ========== */
.nav-tabs {
  background: #fff;
  border-bottom: 1px solid var(--nav-border);
  position: sticky;
  top: 60px;
  z-index: 99;
}

.nav-tabs-inner {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  gap: 4px;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: none;
}

.nav-tabs-inner::-webkit-scrollbar { display: none; }

.nav-tab {
  display: block;
  padding: 12px 16px;
  font-size: 14px;
  font-weight: 500;
  color: var(--nav-text-2);
  white-space: nowrap;
  border-bottom: 2px solid transparent;
  transition: all .2s;
}

.nav-tab:hover { color: var(--nav-primary); }

.nav-tab.active {
  color: var(--nav-primary);
  border-bottom-color: var(--nav-primary);
  font-weight: 600;
}

/* ========== Main ========== */
.nav-main {
  max-width: 1280px;
  margin: 0 auto;
  padding: 24px 24px 48px;
}

/* ========== Section ========== */
.nav-section {
  margin-bottom: 32px;
}

.nav-section.hidden { display: none; }

.nav-section-title {
  font-size: 18px;
  font-weight: 700;
  margin-bottom: 16px;
  padding-left: 12px;
  border-left: 3px solid var(--nav-primary);
  line-height: 1.3;
}

/* ========== Grid ========== */
.nav-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 14px;
}

/* ========== Card ========== */
.nav-card {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 14px 16px;
  background: var(--nav-card-bg);
  border: 1px solid var(--nav-border);
  border-radius: var(--nav-radius);
  transition: all .2s;
  cursor: pointer;
}

.nav-card:hover {
  border-color: var(--nav-primary);
  box-shadow: 0 4px 12px rgba(26,86,219,.1);
  transform: translateY(-2px);
}

.nav-card--highlight {
  border-color: var(--nav-primary);
  background: var(--nav-primary-light);
}

.nav-card--highlight:hover {
  background: #dbe5f9;
}

.nav-card-icon {
  width: 40px;
  height: 40px;
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-size: 16px;
  font-weight: 800;
  flex-shrink: 0;
}

.nav-card-body { min-width: 0; }

.nav-card-name {
  font-size: 14px;
  font-weight: 600;
  line-height: 1.3;
  margin-bottom: 2px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.nav-card-desc {
  font-size: 12px;
  color: var(--nav-text-2);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

/* ========== Footer ========== */
.nav-footer {
  background: #fff;
  border-top: 1px solid var(--nav-border);
  padding: 20px 0;
}

.nav-footer-inner {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 13px;
  color: var(--nav-text-2);
}

.nav-footer a {
  color: var(--nav-primary);
  font-weight: 500;
}

.nav-footer a:hover { text-decoration: underline; }

/* ========== Responsive ========== */
@media (max-width: 768px) {
  .nav-header-inner { gap: 12px; }
  .nav-logo-sep, .nav-logo-sub { display: none; }
  .nav-search { max-width: none; }
  .nav-header-btn { display: none; }
  .nav-grid { grid-template-columns: repeat(auto-fill, minmax(160px, 1fr)); gap: 10px; }
  .nav-card { padding: 10px 12px; gap: 10px; }
  .nav-card-icon { width: 34px; height: 34px; font-size: 14px; border-radius: 8px; }
  .nav-card-name { font-size: 13px; }
  .nav-card-desc { display: none; }
  .nav-section-title { font-size: 16px; }
}