:root {
  --md-sys-shape-corner-large: 16px;
  --md-sys-shape-corner-medium: 12px;

  --page-padding: 24px;
  --max-width: 900px;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  padding: 0;
  font-family: 'Roboto', sans-serif;
  background: var(--md-sys-color-surface);
  color: var(--md-sys-color-on-surface);
  line-height: 1.6;
}

/* 顶栏 */
.top-app-bar {
  position: sticky;
  top: 0;
  z-index: 10;
  background: var(--md-sys-color-surface-container);
  border-bottom: 1px solid var(--md-sys-color-outline-variant);
}

.top-app-bar__content {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 12px var(--page-padding);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.top-app-bar__title {
  font-size: 22px;
  font-weight: 500;
  color: var(--md-sys-color-primary);
  text-decoration: none;
}

/* 主内容 */
main {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--page-padding);
}

/* Hero */
.hero {
  padding: 72px 0 48px;
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 16px;
}

.hero__logo {
  width: 120px;
  height: 120px;
  background: var(--md-sys-color-primary-container);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 8px;
  border-radius: 50% 50% 50% 50% / 50% 50% 50% 50%;
  animation: flower 16s ease-in-out infinite;
}

@keyframes flower {
  0%   { border-radius: 50% 50% 50% 50% / 50% 50% 50% 50%; }
  10%  { border-radius: 55% 45% 52% 48% / 48% 52% 45% 55%; }
  20%  { border-radius: 60% 40% 57% 43% / 44% 56% 41% 59%; }
  30%  { border-radius: 64% 36% 62% 38% / 40% 60% 37% 63%; }
  40%  { border-radius: 66% 34% 65% 35% / 36% 64% 34% 66%; }
  50%  { border-radius: 63% 37% 68% 32% / 33% 67% 38% 62%; }
  60%  { border-radius: 58% 42% 63% 37% / 38% 62% 44% 56%; }
  70%  { border-radius: 53% 47% 56% 44% / 45% 55% 50% 50%; }
  80%  { border-radius: 48% 52% 51% 49% / 51% 49% 54% 46%; }
  90%  { border-radius: 47% 53% 48% 52% / 53% 47% 51% 49%; }
  100% { border-radius: 50% 50% 50% 50% / 50% 50% 50% 50%; }
}

.hero__logo-text {
  font-size: 32px;
  font-weight: 800;
  color: var(--md-sys-color-on-primary-container);
}

.hero__subtitle {
  color: var(--md-sys-color-on-surface-variant);
  max-width: 480px;
}

.hero__actions {
  display: flex;
  gap: 12px;
  margin-top: 16px;
  flex-wrap: wrap;
  justify-content: center;
}

/* 功能卡片 */
.features {
  padding: 24px 0 48px;
}

.features h2 {
  margin-bottom: 20px;
}

.features__grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 16px;
}

.feature-card {
  background: var(--md-sys-color-surface-container);
  border-radius: var(--md-sys-shape-corner-large);
}

.feature-card__content {
  padding: 24px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.feature-card__content md-icon {
  color: var(--md-sys-color-primary);
}

.feature-card__content h3 {
  margin-top: 4px;
}

.feature-card__content p {
  color: var(--md-sys-color-on-surface-variant);
}

/* 链接列表 */
.links {
  padding: 8px 0 48px;
}

.links md-list {
  background: var(--md-sys-color-surface-container);
  border-radius: var(--md-sys-shape-corner-large);
  overflow: hidden;
}

/* 文档页 */
.doc {
  padding: 40px 0 64px;
}

.doc h1 {
  color: var(--md-sys-color-on-surface);
  margin-bottom: 20px;
  font-weight: 500;
}

.doc h2 {
  color: var(--md-sys-color-primary);
  margin-top: 32px;
  margin-bottom: 12px;
  font-size: 20px;
  font-weight: 500;
}

.doc h3 {
  margin-top: 20px;
  margin-bottom: 8px;
  font-size: 16px;
  font-weight: 500;
}

.doc p,
.doc li {
  color: var(--md-sys-color-on-surface-variant);
  margin-bottom: 8px;
}

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

.doc code {
  background: var(--md-sys-color-surface-container-high);
  padding: 2px 6px;
  border-radius: 4px;
  font-family: 'Roboto Mono', monospace;
  font-size: 0.9em;
  color: var(--md-sys-color-primary);
}

/* 页脚 */
.footer {
  padding: 32px var(--page-padding);
  text-align: center;
  color: var(--md-sys-color-on-surface-variant);
  border-top: 1px solid var(--md-sys-color-outline-variant);
  font-size: 13px;
}