/* =============================================================
 * components.css
 * 组件样式: 按钮、卡片、导航、外部资源面板、回到顶部
 * ============================================================= */

/* ===================== 按钮 ===================== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-xs);
  padding: 12px 28px;
  font-size: 15px;
  font-weight: 600;
  border-radius: var(--radius-pill);
  border: 2px solid transparent;
  transition: all var(--duration-fast) var(--ease-out);
  text-decoration: none;
  white-space: nowrap;
  user-select: none;
  cursor: pointer;
}

.btn--primary {
  background: var(--color-primary);
  color: #fff;
  border-color: var(--color-primary);
}

.btn--primary:hover {
  background: var(--color-primary-dark);
  border-color: var(--color-primary-dark);
  color: #fff;
  transform: translateY(-1px);
  box-shadow: 0 8px 16px rgba(39, 115, 247, 0.25);
}

.btn--primary:active {
  transform: translateY(0);
}

.btn--white {
  background: #fff;
  color: var(--color-primary);
  border-color: #fff;
}

.btn--white:hover {
  background: var(--color-primary);
  color: #fff;
  border-color: var(--color-primary);
}

.btn--lg {
  padding: 14px 30px 13px;
  font-size: 15px;
}

/* ===================== 下载卡 ===================== */
.download-card {
  background: #fff;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--space-lg) var(--space-md);
  text-align: center;
  transition: all var(--duration-base) var(--ease-out);
}

.download-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
  border-color: var(--color-primary);
}

.download-card__icon {
  width: 160px;
  height: 160px;
  margin: 0 auto var(--space-md);
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--color-bg-alt);
  border-radius: var(--radius-md);
  overflow: hidden;
}

.download-card__icon img {
  width: 100%;
  height: 100%;
  object-fit: contain;
  padding: 12px;
}

.download-card__icon--svg {
  background: var(--color-bg-soft);
}

.download-card__icon--svg svg {
  width: 72px;
  height: 72px;
}

.download-card__title {
  font-size: 20px;
  font-weight: 600;
  margin-bottom: var(--space-sm);
}

.download-card__title a {
  color: var(--color-primary);
  text-decoration: none;
}

.download-card__title a:hover {
  color: var(--color-primary-dark);
}

.download-card__desc {
  font-size: 14px;
  color: var(--color-text);
  line-height: 1.8;
  margin: 0;
}

/* ===================== 移动端汉堡菜单 ===================== */
.site-nav__toggle {
  display: none;
  width: 40px;
  height: 40px;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 5px;
  padding: 8px;
  border-radius: var(--radius-sm);
}

.site-nav__toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--color-heading);
  border-radius: 2px;
  transition: all var(--duration-fast) var(--ease-out);
}

.site-nav__toggle[aria-expanded="true"] span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.site-nav__toggle[aria-expanded="true"] span:nth-child(2) {
  opacity: 0;
}

.site-nav__toggle[aria-expanded="true"] span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

@media (max-width: 880px) {
  .site-nav__toggle {
    display: flex;
  }

  .site-nav {
    position: fixed;
    top: 80px;
    right: 0;
    width: min(80%, 320px);
    height: calc(100vh - 80px);
    background: #fff;
    border-left: 1px solid var(--color-border);
    padding: var(--space-md);
    transform: translateX(100%);
    transition: transform var(--duration-base) var(--ease-out);
    box-shadow: var(--shadow-lg);
    overflow-y: auto;
  }

  .site-nav.is-open {
    transform: translateX(0);
  }

  .site-nav__list {
    flex-direction: column;
    align-items: stretch;
  }

  .site-nav__list li {
    margin: 0;
    border-bottom: 1px solid var(--color-border);
  }

  .site-nav__link {
    display: block;
    padding: var(--space-md) var(--space-sm);
    color: var(--color-heading);
  }
}

@media (min-width: 881px) {
  .site-nav__list {
    display: flex;
    align-items: center;
    gap: var(--space-lg);
  }

  .site-nav__link {
    color: var(--color-heading);
    font-size: 15px;
    font-weight: 500;
    padding: 8px 0;
    position: relative;
  }

  .site-nav__link::after {
    content: '';
    position: absolute;
    left: 0;
    bottom: 0;
    width: 0;
    height: 2px;
    background: var(--color-primary);
    transition: width var(--duration-base) var(--ease-out);
  }

  .site-nav__link:hover::after,
  .site-nav__link.is-active::after {
    width: 100%;
  }
}

/* ===================== 回到顶部 ===================== */
.to-top {
  position: fixed;
  bottom: 30px;
  left: 30px;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--color-primary);
  color: #fff;
  font-size: 20px;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow-md);
  z-index: 90;
  opacity: 0;
  pointer-events: none;
  transform: translateY(20px);
  transition: all var(--duration-base) var(--ease-out);
}

.to-top.is-visible {
  opacity: 1;
  pointer-events: auto;
  transform: translateY(0);
}

.to-top:hover {
  background: var(--color-primary-dark);
  transform: translateY(-2px);
}

/* ===================== 外部资源面板 =====================
   固定在右下角,小尺寸,不抢占主视觉空间
   列出所有 data-ext-id 标记的外部资源
   ============================================================= */
.ext-panel {
  position: fixed;
  bottom: 20px;
  right: 20px;
  width: 320px;
  max-width: calc(100vw - 40px);
  background: #fff;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  z-index: 200;
  font-size: 13px;
  overflow: hidden;
}

.ext-panel__toggle {
  width: 100%;
  display: flex;
  align-items: center;
  gap: var(--space-xs);
  padding: 10px 14px;
  background: var(--color-heading);
  color: #fff;
  font-weight: 600;
  text-align: left;
  font-size: 13px;
}

.ext-panel__toggle:hover {
  background: #2a3a3a;
}

.ext-panel__dot {
  width: 8px;
  height: 8px;
  background: var(--color-accent);
  border-radius: 50%;
  display: inline-block;
  flex-shrink: 0;
  box-shadow: 0 0 0 0 rgba(255, 97, 55, 0.5);
  animation: pulse-dot 2s infinite;
}

.ext-panel__count {
  margin-left: auto;
  background: rgba(255, 255, 255, 0.2);
  border-radius: 999px;
  padding: 2px 8px;
  font-size: 12px;
  min-width: 22px;
  text-align: center;
}

.ext-panel__body {
  max-height: 320px;
  overflow-y: auto;
  padding: var(--space-sm) var(--space-md);
  background: #fafbfc;
}

.ext-panel__body h5 {
  font-size: 12px;
  color: var(--color-heading);
  margin: 4px 0 8px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.ext-panel__list {
  margin: 0 0 var(--space-xs);
  padding: 0;
  list-style: none;
}

.ext-panel__list li {
  padding: 6px 0;
  border-bottom: 1px dashed #e3e6ea;
  font-size: 12px;
  color: #555;
  line-height: 1.5;
  word-break: break-all;
}

.ext-panel__list li:last-child {
  border-bottom: 0;
}

.ext-panel__list code {
  display: inline-block;
  background: #eef3fb;
  color: var(--color-primary);
  padding: 1px 6px;
  border-radius: 4px;
  font-size: 11px;
  font-family: 'SF Mono', 'Consolas', monospace;
  margin-right: 4px;
}

.ext-panel__list .ext-url {
  color: #888;
  font-size: 11px;
  display: block;
  margin-top: 2px;
  word-break: break-all;
}

.ext-panel__hint {
  margin: 0;
  font-size: 11px;
  color: #888;
  line-height: 1.5;
}

.ext-panel__hint code {
  background: #eef3fb;
  padding: 1px 4px;
  border-radius: 3px;
  font-family: 'SF Mono', 'Consolas', monospace;
}

@media (max-width: 480px) {
  .ext-panel {
    bottom: 10px;
    right: 10px;
    width: calc(100vw - 20px);
  }

  .to-top {
    bottom: 80px;
    left: 15px;
  }
}