/* 全局组件：导航、页脚、按钮、卡片、表单 */

/* ========== 顶部导航 ========== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  height: var(--header-height);
  background: var(--color-bg);
  border-bottom: 1px solid var(--color-silver-accent);
  transition: box-shadow var(--transition-fast);
}
.site-header.is-scrolled { box-shadow: var(--shadow-header); }
.site-header .inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--gutter);
}
.site-logo {
  font-size: 20px;
  font-weight: var(--font-semibold);
  color: var(--color-dark);
}
.site-logo:hover { color: var(--color-primary); }
.site-nav {
  display: flex;
  align-items: center;
  gap: var(--space-4);
}
.site-nav a {
  color: var(--color-dark);
  font-size: var(--text-nav);
  font-weight: var(--font-medium);
}
.site-nav a:hover,
.site-nav a.active { color: var(--color-primary); }
.site-nav a.active { position: relative; }
.site-nav a.active::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: -4px;
  height: 2px;
  background: var(--color-primary);
  border-radius: 1px;
}

/* 移动端汉堡菜单 */
.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 40px;
  height: 40px;
  padding: 8px;
  background: none;
  border: none;
  cursor: pointer;
  border-radius: var(--radius-input);
}
.nav-toggle span {
  display: block;
  width: 100%;
  height: 2px;
  background: var(--color-dark);
  border-radius: 1px;
  transition: var(--transition-fast);
}
.nav-toggle[aria-expanded="true"] span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}
.nav-toggle[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
.nav-toggle[aria-expanded="true"] span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}
@media (max-width: 767px) {
  .nav-toggle { display: flex; }
  .site-nav {
    position: fixed;
    top: var(--header-height);
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--color-bg);
    flex-direction: column;
    justify-content: flex-start;
    padding: var(--space-4);
    gap: 0;
    transform: translateX(100%);
    transition: transform var(--transition-fast);
    overflow-y: auto;
  }
  .site-nav.is-open { transform: translateX(0); }
  .site-nav a {
    display: block;
    padding: var(--space-2) 0;
    border-bottom: 1px solid var(--color-silver-accent);
    font-size: 16px;
  }
  .site-nav .btn { margin-top: var(--space-2); }
}

/* ========== 按钮 ========== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 24px;
  font-family: inherit;
  font-size: 16px;
  font-weight: var(--font-medium);
  line-height: 1.5;
  border-radius: var(--radius-btn);
  border: none;
  cursor: pointer;
  transition: background-color var(--transition-fast), transform var(--transition-fast);
}
.btn:focus-visible { outline: 2px solid var(--color-primary); outline-offset: 2px; }
.btn:disabled { opacity: 0.6; cursor: not-allowed; }
.btn-primary {
  background: var(--color-primary);
  color: #fff;
}
.btn-primary:hover:not(:disabled) {
  background: var(--color-primary-hover);
}
.btn-secondary {
  background: transparent;
  color: var(--color-primary);
  border: 1px solid var(--color-primary);
}
.btn-secondary:hover:not(:disabled) {
  background: var(--color-primary-light);
}
.btn-large { padding: 14px 32px; }
.btn-secondary.btn-inverse {
  color: rgba(255,255,255,0.9);
  border-color: rgba(255,255,255,0.6);
}
.btn-secondary.btn-inverse:hover:not(:disabled) {
  background: rgba(255,255,255,0.1);
  color: #fff;
}

/* ========== 卡片（可点击） ========== */
.card {
  padding: var(--space-3);
  background: var(--color-bg);
  border: 1px solid var(--color-silver-accent);
  border-radius: var(--radius-card);
  box-shadow: var(--shadow-card);
  transition: box-shadow var(--transition-fast), transform var(--transition-fast), border-color var(--transition-fast);
}
.card:hover {
  box-shadow: var(--shadow-card-hover);
  border-color: var(--color-primary);
  transform: translateY(-2px);
}
.card-link {
  display: block;
  color: inherit;
  text-decoration: none;
}
.card-link:hover { color: inherit; }
.card-link:focus-visible { outline-offset: 4px; }
.card-icon {
  width: 48px;
  height: 48px;
  margin-bottom: var(--space-2);
  color: var(--color-primary);
}
.card h3 { margin-bottom: var(--space-1); }
.card p {
  font-size: var(--text-small);
  color: var(--color-silver);
  line-height: 1.5;
  margin: 0;
}

/* ========== 页脚 ========== */
.site-footer {
  background: var(--color-dark);
  color: rgba(255,255,255,0.85);
}
.footer-top {
  padding: var(--space-6) var(--gutter);
  max-width: var(--container-max);
  margin: 0 auto;
}
.footer-top .section-title .title,
.footer-top .section-title .subtitle { color: rgba(255,255,255,0.95); }
.footer-top .section-title .subtitle { color: rgba(255,255,255,0.7); }
.footer-contact {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-4);
  margin-bottom: var(--space-4);
}
.footer-contact a {
  color: inherit;
  display: flex;
  align-items: center;
  gap: var(--space-1);
}
.footer-contact a:hover { color: #fff; }
.footer-buttons {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
}
.footer-bottom {
  padding: var(--space-3) var(--gutter);
  border-top: 1px solid rgba(255,255,255,0.1);
  text-align: center;
  font-size: var(--text-small);
  color: rgba(255,255,255,0.6);
}
.footer-bottom a { color: rgba(255,255,255,0.8); }
.footer-bottom .footer-links { margin-top: 8px; }
.footer-bottom .footer-links a:hover { color: #fff; }

/* ========== 表单 ========== */
.form-group {
  margin-bottom: var(--space-3);
}
.form-group label {
  display: block;
  font-size: var(--text-small);
  color: var(--color-dark-secondary);
  margin-bottom: var(--space-1);
}
.form-group label .required { color: var(--color-error); }
.form-group input,
.form-group textarea {
  width: 100%;
  padding: 12px 16px;
  font-family: inherit;
  font-size: 16px;
  line-height: 1.5;
  color: var(--color-dark);
  background: var(--color-bg);
  border: 1px solid var(--color-silver-accent);
  border-radius: var(--radius-input);
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}
.form-group input:focus,
.form-group textarea:focus {
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px var(--color-primary-light);
  outline: none;
}
.form-group input.error,
.form-group textarea.error {
  border-color: var(--color-error);
}
.form-group textarea {
  min-height: 120px;
  resize: vertical;
}
.form-error {
  font-size: 12px;
  color: var(--color-error);
  margin-top: var(--space-1);
}
.form-error-block {
  padding: var(--space-3);
  background: rgba(220, 38, 38, 0.08);
  color: var(--color-error);
  border-radius: var(--radius-input);
  margin-bottom: var(--space-3);
  font-size: var(--text-small);
}
.form-success {
  padding: var(--space-3);
  background: rgba(5, 150, 105, 0.1);
  color: var(--color-success);
  border-radius: var(--radius-input);
  margin-bottom: var(--space-3);
}