/* =========================================================
   Material Design 3 — Base & Components
   ========================================================= */

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

html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }

body {
  font-family: "Roboto", "Roboto Flex", "WenQuanYi Micro Hei", "Microsoft YaHei", system-ui, sans-serif;
  background-color: var(--md-sys-color-background);
  color: var(--md-sys-color-on-background);
  font-size: var(--md-sys-typescale-body-large-font);
  line-height: var(--md-sys-typescale-body-large-line-height);
  -webkit-font-smoothing: antialiased;
  transition: background-color var(--md-sys-motion-duration-medium2) var(--md-sys-motion-easing-standard),
              color var(--md-sys-motion-duration-medium2) var(--md-sys-motion-easing-standard);
}

img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
ul { list-style: none; }
button { font-family: inherit; cursor: pointer; border: none; background: none; }

::selection {
  background-color: var(--md-sys-color-primary-container);
  color: var(--md-sys-color-on-primary-container);
}

/* 滚动条（用 surface-variant） */
::-webkit-scrollbar { width: 10px; height: 10px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb {
  background: var(--md-sys-color-surface-variant);
  border-radius: var(--md-sys-shape-corner-full);
}

/* ---------- Typography Roles ---------- */
.md-typescale-display-large {
  font-size: var(--md-sys-typescale-display-large-font);
  font-weight: var(--md-sys-typescale-display-large-weight);
  line-height: var(--md-sys-typescale-display-large-line-height);
  letter-spacing: var(--md-sys-typescale-display-large-tracking);
}
.md-typescale-display-small {
  font-size: var(--md-sys-typescale-display-small-font);
  font-weight: var(--md-sys-typescale-display-small-weight);
  line-height: var(--md-sys-typescale-display-small-line-height);
}
.md-typescale-headline-large {
  font-size: var(--md-sys-typescale-headline-large-font);
  font-weight: var(--md-sys-typescale-headline-large-weight);
  line-height: var(--md-sys-typescale-headline-large-line-height);
}
.md-typescale-headline-medium {
  font-size: var(--md-sys-typescale-headline-medium-font);
  font-weight: var(--md-sys-typescale-headline-medium-weight);
  line-height: var(--md-sys-typescale-headline-medium-line-height);
}
.md-typescale-headline-small {
  font-size: var(--md-sys-typescale-headline-small-font);
  font-weight: var(--md-sys-typescale-headline-small-weight);
  line-height: var(--md-sys-typescale-headline-small-line-height);
}
.md-typescale-title-large {
  font-size: var(--md-sys-typescale-title-large-font);
  font-weight: var(--md-sys-typescale-title-large-weight);
  line-height: var(--md-sys-typescale-title-large-line-height);
}
.md-typescale-title-medium {
  font-size: var(--md-sys-typescale-title-medium-font);
  font-weight: var(--md-sys-typescale-title-medium-weight);
  line-height: var(--md-sys-typescale-title-medium-line-height);
  letter-spacing: var(--md-sys-typescale-title-medium-tracking);
}
.md-typescale-title-small {
  font-size: var(--md-sys-typescale-title-small-font);
  font-weight: var(--md-sys-typescale-title-small-weight);
  line-height: var(--md-sys-typescale-title-small-line-height);
  letter-spacing: var(--md-sys-typescale-title-small-tracking);
}
.md-typescale-body-large {
  font-size: var(--md-sys-typescale-body-large-font);
  font-weight: var(--md-sys-typescale-body-large-weight);
  line-height: var(--md-sys-typescale-body-large-line-height);
  letter-spacing: var(--md-sys-typescale-body-large-tracking);
}
.md-typescale-body-medium {
  font-size: var(--md-sys-typescale-body-medium-font);
  font-weight: var(--md-sys-typescale-body-medium-weight);
  line-height: var(--md-sys-typescale-body-medium-line-height);
  letter-spacing: var(--md-sys-typescale-body-medium-tracking);
}
.md-typescale-body-small {
  font-size: var(--md-sys-typescale-body-small-font);
  font-weight: var(--md-sys-typescale-body-small-weight);
  line-height: var(--md-sys-typescale-body-small-line-height);
  letter-spacing: var(--md-sys-typescale-body-small-tracking);
}
.md-typescale-label-large {
  font-size: var(--md-sys-typescale-label-large-font);
  font-weight: var(--md-sys-typescale-label-large-weight);
  line-height: var(--md-sys-typescale-label-large-line-height);
  letter-spacing: var(--md-sys-typescale-label-large-tracking);
}
.md-typescale-label-medium {
  font-size: var(--md-sys-typescale-label-medium-font);
  font-weight: var(--md-sys-typescale-label-medium-weight);
  line-height: var(--md-sys-typescale-label-medium-line-height);
  letter-spacing: var(--md-sys-typescale-label-medium-tracking);
}

/* 文本颜色角色 */
.md-on-surface-variant { color: var(--md-sys-color-on-surface-variant); }
.md-primary { color: var(--md-sys-color-primary); }

/* 简介大段落 */
.md-intro {
  max-width: 840px;
  margin: 0 auto;
  text-align: center;
  line-height: 1.8;
  color: var(--md-sys-color-on-surface);
}

/* ---------- Layout 容器 ---------- */
.md-container {
  width: 100%;
  max-width: var(--md-layout-max-width);
  margin: 0 auto;
  padding: 0 var(--md-layout-gutter);
}
.md-section {
  padding: 96px 0;
}
.md-section-header {
  text-align: center;
  margin-bottom: 64px;
}
.md-section-header .md-typescale-headline-small {
  color: var(--md-sys-color-primary);
  text-transform: uppercase;
  letter-spacing: 2px;
  margin-bottom: 12px;
}
.md-section-header h2 {
  font-size: var(--md-sys-typescale-headline-medium-font);
  font-weight: var(--md-sys-typescale-headline-medium-weight);
  line-height: var(--md-sys-typescale-headline-medium-line-height);
  margin-bottom: 16px;
}

/* =========================================================
   组件
   ========================================================= */

/* ---------- Top App Bar (small) ---------- */
.md-top-app-bar {
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--md-top-app-bar-height);
  background-color: var(--md-sys-color-surface);
  display: flex;
  align-items: center;
  padding: 0 var(--md-layout-gutter);
  /* Elevation Level 2: tonal + 轻阴影 */
  border-bottom: 1px solid var(--md-sys-color-outline-variant);
  transition: background-color var(--md-sys-motion-duration-medium2) var(--md-sys-motion-easing-standard);
}
.md-top-app-bar__inner {
  width: 100%;
  max-width: var(--md-layout-max-width);
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}
.md-top-app-bar__brand {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: var(--md-sys-typescale-title-large-font);
  font-weight: var(--md-sys-typescale-title-large-weight);
  color: var(--md-sys-color-on-surface);
}
.md-top-app-bar__logo {
  width: 36px;
  height: 36px;
  border-radius: var(--md-sys-shape-corner-medium);
  background-color: var(--md-sys-color-primary-container);
  color: var(--md-sys-color-on-primary-container);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 20px;
  font-weight: 600;
}
.md-top-app-bar__nav {
  display: flex;
  align-items: center;
  gap: 4px;
}
.md-top-app-bar__nav a {
  position: relative;
  height: 40px;
  padding: 0 16px;
  border-radius: var(--md-sys-shape-corner-full);
  display: flex;
  align-items: center;
  font-size: var(--md-sys-typescale-label-large-font);
  font-weight: var(--md-sys-typescale-label-large-weight);
  letter-spacing: var(--md-sys-typescale-label-large-tracking);
  color: var(--md-sys-color-on-surface);
  overflow: hidden;
  transition: background-color var(--md-sys-motion-duration-short3) var(--md-sys-motion-easing-standard);
}
.md-top-app-bar__nav a::before {
  content: "";
  position: absolute; inset: 0;
  background-color: var(--md-sys-color-on-surface);
  opacity: 0;
  transition: opacity var(--md-sys-motion-duration-short3) var(--md-sys-motion-easing-standard);
}
.md-top-app-bar__nav a:hover::before { opacity: var(--md-state-hover-opacity); }
.md-top-app-bar__nav a:active::before { opacity: var(--md-state-pressed-opacity); }
.md-top-app-bar__nav a > span { position: relative; z-index: 1; }
.md-top-app-bar__nav a.active {
  background-color: var(--md-sys-color-secondary-container);
  color: var(--md-sys-color-on-secondary-container);
}

@media (max-width: 599px) {
  .md-top-app-bar__nav { display: none; }
}

/* ---------- Icon Button ---------- */
.md-icon-button {
  position: relative;
  width: var(--md-comp-icon-button-size);
  height: var(--md-comp-icon-button-size);
  min-width: var(--md-comp-touch-target);
  min-height: var(--md-comp-touch-target);
  border-radius: var(--md-sys-shape-corner-full);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: var(--md-sys-color-on-surface-variant);
  overflow: hidden;
  transition: background-color var(--md-sys-motion-duration-short3) var(--md-sys-motion-easing-standard);
}
.md-icon-button::before {
  content: "";
  position: absolute; inset: 0;
  background-color: currentColor;
  opacity: 0;
  transition: opacity var(--md-sys-motion-duration-short3) var(--md-sys-motion-easing-standard);
}
.md-icon-button:hover::before { opacity: var(--md-state-hover-opacity); }
.md-icon-button:active::before { opacity: var(--md-state-pressed-opacity); }
.md-icon-button svg { position: relative; z-index: 1; width: var(--md-comp-icon-size); height: var(--md-comp-icon-size); }

/* ---------- Buttons ---------- */
.md-button {
  position: relative;
  height: var(--md-comp-button-height);
  min-width: 64px;
  padding: 0 24px;
  border-radius: var(--md-sys-shape-corner-full);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  font-size: var(--md-sys-typescale-label-large-font);
  font-weight: var(--md-sys-typescale-label-large-weight);
  letter-spacing: var(--md-sys-typescale-label-large-tracking);
  line-height: var(--md-sys-typescale-label-large-line-height);
  overflow: hidden;
  transition: background-color var(--md-sys-motion-duration-short3) var(--md-sys-motion-easing-standard),
              box-shadow var(--md-sys-motion-duration-short3) var(--md-sys-motion-easing-standard);
}
.md-button__label { position: relative; z-index: 1; display: inline-flex; align-items: center; gap: 8px; }
.md-button__state {
  position: absolute; inset: 0;
  background-color: currentColor;
  opacity: 0;
  transition: opacity var(--md-sys-motion-duration-short3) var(--md-sys-motion-easing-standard);
}
.md-button:hover .md-button__state { opacity: var(--md-state-hover-opacity); }
.md-button:active .md-button__state { opacity: var(--md-state-pressed-opacity); }

.md-button--filled {
  background-color: var(--md-sys-color-primary);
  color: var(--md-sys-color-on-primary);
  box-shadow: 0 1px 2px rgba(0,0,0,0.30), 0 1px 3px 1px rgba(0,0,0,0.15);
}
.md-button--tonal {
  background-color: var(--md-sys-color-secondary-container);
  color: var(--md-sys-color-on-secondary-container);
}
.md-button--outlined {
  background-color: transparent;
  color: var(--md-sys-color-primary);
  border: 1px solid var(--md-sys-color-outline);
}
.md-button--text {
  background-color: transparent;
  color: var(--md-sys-color-primary);
  padding: 0 12px;
}
.md-button--large { height: 48px; padding: 0 32px; font-size: 15px; }

/* ---------- FAB (M3 用 primaryContainer) ---------- */
.md-fab {
  position: fixed;
  right: 32px;
  bottom: 32px;
  width: var(--md-comp-fab-size);
  height: var(--md-comp-fab-size);
  min-width: var(--md-comp-touch-target);
  min-height: var(--md-comp-touch-target);
  border-radius: var(--md-sys-shape-corner-large);
  background-color: var(--md-sys-color-primary-container);
  color: var(--md-sys-color-on-primary-container);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 3px 5px rgba(0,0,0,0.30), 0 6px 10px 4px rgba(0,0,0,0.15); /* Level 3 */
  z-index: 90;
  transition: background-color var(--md-sys-motion-duration-short3) var(--md-sys-motion-easing-standard),
              box-shadow var(--md-sys-motion-duration-short3) var(--md-sys-motion-easing-standard);
}
.md-fab:hover { box-shadow: 0 5px 5px rgba(0,0,0,0.30), 0 9px 14px 6px rgba(0,0,0,0.15); }
.md-fab:active { box-shadow: 0 2px 5px rgba(0,0,0,0.30), 0 5px 8px 3px rgba(0,0,0,0.15); }
.md-fab svg { width: var(--md-comp-icon-size); height: var(--md-comp-icon-size); }
@media (max-width: 599px) {
  .md-fab { right: 16px; bottom: 16px; }
}

/* ---------- Hero ---------- */
.md-hero {
  position: relative;
  min-height: calc(100vh - var(--md-top-app-bar-height));
  display: flex;
  align-items: center;
  overflow: hidden;
  background-color: var(--md-sys-color-surface);
}
.md-hero__grid {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 64px;
  align-items: center;
}
.md-hero__content { animation: fade-up var(--md-sys-motion-duration-long2) var(--md-sys-motion-easing-emphasized-decelerate) both; }
.md-hero__eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 16px;
  border-radius: var(--md-sys-shape-corner-full);
  background-color: var(--md-sys-color-secondary-container);
  color: var(--md-sys-color-on-secondary-container);
  margin-bottom: 32px;
}
.md-hero h1 {
  font-size: clamp(40px, 6vw, var(--md-sys-typescale-display-large-font));
  font-weight: var(--md-sys-typescale-display-large-weight);
  line-height: 1.1;
  letter-spacing: var(--md-sys-typescale-display-large-tracking);
  margin-bottom: 24px;
  color: var(--md-sys-color-on-surface);
}
.md-hero h1 .accent { color: var(--md-sys-color-primary); }
.md-hero__lead {
  font-size: var(--md-sys-typescale-headline-small-font);
  font-weight: 400;
  line-height: var(--md-sys-typescale-headline-small-line-height);
  color: var(--md-sys-color-on-surface-variant);
  margin-bottom: 40px;
  max-width: 520px;
}
.md-hero__actions { display: flex; gap: 16px; flex-wrap: wrap; }

/* Hero visual: 用 surface container + 多张卡片模拟产品 */
.md-hero__visual {
  position: relative;
  /* 高度由内容决定（16:9 主体由宽度推导 + gap + 控件条），
     这样 grid 的 align-items:center 才能让它与左侧文字真正同轴居中 */
  display: flex;
  flex-direction: column;
  gap: 16px;
  animation: fade-in var(--md-sys-motion-duration-long2) var(--md-sys-motion-easing-emphasized-decelerate) 120ms both;
}

/* ---------- 轮播主体 ---------- */
.md-hero__slides {
  position: relative;
  width: 100%;
  /* 严格 16:9 */
  aspect-ratio: 16 / 9;
  border-radius: var(--md-sys-shape-corner-extra-large);
  overflow: hidden;
  background-color: var(--md-sys-color-surface-container-highest);
  box-shadow: 0 1px 2px rgba(0,0,0,0.30), 0 6px 12px 4px rgba(0,0,0,0.15); /* Level 3 */
  isolation: isolate;
}

.md-hero__slide {
  position: absolute;
  inset: 0;
  margin: 0;
  opacity: 0;
  transform: scale(1.04);
  transition: opacity var(--md-sys-motion-duration-medium3) var(--md-sys-motion-easing-emphasized),
              transform 600ms var(--md-sys-motion-easing-emphasized);
  will-change: opacity, transform;
}
.md-hero__slide.is-active {
  opacity: 1;
  transform: scale(1);
  z-index: 1;
}
.md-hero__slide img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center;
}

/* 图片底部渐变 + 说明文字（用 on-surface 保证双主题可读） */
.md-hero__caption {
  position: absolute;
  left: 0; right: 0; bottom: 0;
  display: flex;
  flex-direction: column;
  gap: 2px;
  padding: 56px 28px 22px;
  color: var(--md-sys-color-on-surface);
  background: linear-gradient(
    to top,
    rgba(0,0,0,0.62) 0%,
    rgba(0,0,0,0.34) 55%,
    rgba(0,0,0,0) 100%
  );
}
.md-hero__caption,
.md-hero__caption > * { color: #fff; }
.md-hero__caption > .md-typescale-body-small { opacity: 0.9; }

/* ---------- 底部控件条 ---------- */
.md-hero__controls {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 0 4px;
  /* 脱离文档流挂在图片下方：让 .md-hero__visual 高度 = 图片主体高度，
     图片中心才能与左侧文字中心严格同轴 */
  position: absolute;
  top: 100%;
  left: 0;
  right: 0;
  margin-top: 16px;
}

.md-hero__dots { display: flex; gap: 8px; }

.md-hero__dot {
  width: 24px;
  height: 24px;
  min-width: 24px;
  min-height: 24px;
  border-radius: var(--md-sys-shape-corner-full);
  padding: 0;
  position: relative;
  /* 触控目标 48x48，用 padding 撑大但不影响视觉 */
  box-shadow: 0 0 0 12px transparent;
}
.md-hero__dot::after {
  content: "";
  position: absolute;
  top: 50%; left: 50%;
  transform: translate(-50%, -50%);
  width: 8px; height: 8px;
  border-radius: var(--md-sys-shape-corner-full);
  background-color: var(--md-sys-color-on-surface-variant);
  transition: width var(--md-sys-motion-duration-short4) var(--md-sys-motion-easing-standard),
              height var(--md-sys-motion-duration-short4) var(--md-sys-motion-easing-standard),
              background-color var(--md-sys-motion-duration-short4) var(--md-sys-motion-easing-standard);
}
.md-hero__dot:hover::after { background-color: var(--md-sys-color-primary); }
.md-hero__dot.is-active::after {
  width: 24px;
  height: 8px;
  background-color: var(--md-sys-color-primary);
}
.md-hero__dot:focus-visible {
  outline: 3px solid var(--md-sys-color-primary);
  outline-offset: 2px;
}

.md-hero__pager {
  display: flex;
  align-items: center;
  gap: 4px;
  color: var(--md-sys-color-on-surface-variant);
}
.md-hero__count {
  display: inline-flex;
  align-items: baseline;
  gap: 3px;
  font-variant-numeric: tabular-nums;
  padding: 0 8px;
}
.md-hero__count b {
  font-size: var(--md-sys-typescale-title-small-font);
  font-weight: var(--md-sys-typescale-title-small-weight);
  color: var(--md-sys-color-on-surface);
}
.md-hero__count i { font-style: normal; opacity: 0.6; }

/* 减少动效偏好 */
@media (prefers-reduced-motion: reduce) {
  .md-hero__slide { transition: opacity 1ms linear; transform: none; }
}

@media (max-width: 839px) {
  .md-hero { min-height: auto; padding: 64px 0; }
  .md-hero__grid { grid-template-columns: 1fr; gap: 48px; }
  .md-hero__visual { order: -1; }
  /* 单列时控件条回到文档流，避免溢出与下方文字重叠 */
  .md-hero__controls { position: static; margin-top: 0; }
  .md-hero__caption { padding: 40px 20px 16px; }
}

/* ---------- Feature Cards (filled card 型) ---------- */
.md-features__grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}
.md-card {
  position: relative;
  background-color: var(--md-sys-color-surface-container-low);
  border-radius: var(--md-comp-radius-surface);
  padding: var(--md-comp-card-padding);
  overflow: hidden;
  transition: background-color var(--md-sys-motion-duration-short3) var(--md-sys-motion-easing-standard),
              box-shadow var(--md-sys-motion-duration-short3) var(--md-sys-motion-easing-standard),
              transform var(--md-sys-motion-duration-medium2) var(--md-sys-motion-easing-emphasized);
}
.md-card::before {
  content: "";
  position: absolute; inset: 0;
  background-color: var(--md-sys-color-on-surface);
  opacity: 0;
  transition: opacity var(--md-sys-motion-duration-short3) var(--md-sys-motion-easing-standard);
}
.md-card:hover { transform: translateY(-4px); box-shadow: 0 2px 6px rgba(0,0,0,0.30), 0 4px 10px 3px rgba(0,0,0,0.15); }
.md-card:hover::before { opacity: var(--md-state-hover-opacity); }
.md-card > * { position: relative; z-index: 1; }

.md-card__icon {
  width: 56px; height: 56px;
  border-radius: var(--md-sys-shape-corner-medium);
  display: flex; align-items: center; justify-content: center;
  margin-bottom: 20px;
}
.md-card__icon svg { width: 28px; height: 28px; }
.md-card__title { margin-bottom: 8px; }
.md-card__text { color: var(--md-sys-color-on-surface-variant); }

/* elevated card（加 tonal 层） */
.md-card--elevated {
  background-color: var(--md-sys-color-surface-container-low);
  box-shadow: 0 1px 2px rgba(0,0,0,0.30), 0 1px 3px 1px rgba(0,0,0,0.15); /* Level 1 */
}
.md-card--filled { background-color: var(--md-sys-color-surface-container-high); }
.md-card--outlined {
  background-color: var(--md-sys-color-surface);
  border: 1px solid var(--md-sys-color-outline-variant);
}

@media (max-width: 839px) {
  .md-features__grid { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 599px) {
  .md-features__grid { grid-template-columns: 1fr; }
  .md-section { padding: 64px 0; }
  .md-section-header { margin-bottom: 40px; }
}

/* ---------- Stats ---------- */
.md-stats {
  background-color: var(--md-sys-color-surface-container-low);
}
.md-stats__grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}
.md-stat {
  text-align: center;
  padding: 32px 16px;
  border-radius: var(--md-comp-radius-surface);
  background-color: var(--md-sys-color-surface-container);
}
.md-stat__num {
  font-size: 48px;
  font-weight: var(--md-sys-typescale-display-small-weight);
  line-height: 1;
  color: var(--md-sys-color-primary);
  margin-bottom: 12px;
}
@media (max-width: 839px) { .md-stats__grid { grid-template-columns: repeat(2, 1fr); } }

/* ---------- Product Showcase ---------- */
.md-showcase__grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 64px;
  align-items: center;
}
.md-showcase__grid--single {
  grid-template-columns: 1fr;
  max-width: 900px;
  margin: 0 auto;
}
.md-showcase__list { display: flex; flex-direction: column; gap: 16px; }
.md-showcase__item {
  display: flex;
  gap: 16px;
  padding: 20px;
  border-radius: var(--md-comp-radius-surface);
  background-color: var(--md-sys-color-surface-container-low);
  transition: background-color var(--md-sys-motion-duration-short3) var(--md-sys-motion-easing-standard);
}
.md-showcase__item:hover { background-color: var(--md-sys-color-surface-container); }
.md-showcase__check {
  width: 32px; height: 32px;
  min-width: 32px;
  border-radius: var(--md-sys-shape-corner-full);
  background-color: var(--md-sys-color-tertiary-container);
  color: var(--md-sys-color-on-tertiary-container);
  display: flex; align-items: center; justify-content: center;
}
.md-showcase__check svg { width: 20px; height: 20px; }
.md-showcase__item h4 { margin-bottom: 4px; }
.md-showcase__item p { color: var(--md-sys-color-on-surface-variant); }

.md-showcase__visual {
  border-radius: var(--md-sys-shape-corner-extra-large);
  background-color: var(--md-sys-color-surface-container-high);
  padding: 32px;
  box-shadow: 0 1px 2px rgba(0,0,0,0.30), 0 2px 6px 2px rgba(0,0,0,0.15);
}

/* Tabs */
.md-tabs {
  display: flex;
  gap: 8px;
  margin-bottom: 24px;
  border-bottom: 1px solid var(--md-sys-color-outline-variant);
}
.md-tab {
  position: relative;
  height: 48px;
  padding: 0 16px;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  color: var(--md-sys-color-on-surface-variant);
  font-size: var(--md-sys-typescale-title-small-font);
  font-weight: var(--md-sys-typescale-title-small-weight);
  overflow: hidden;
  transition: color var(--md-sys-motion-duration-short3) var(--md-sys-motion-easing-standard);
}
.md-tab::after {
  content: "";
  position: absolute;
  bottom: 0; left: 16px; right: 16px;
  height: 3px;
  border-radius: var(--md-sys-shape-corner-extra-small) var(--md-sys-shape-corner-extra-small) 0 0;
  background-color: var(--md-sys-color-primary);
  transform: scaleX(0);
  transition: transform var(--md-sys-motion-duration-short4) var(--md-sys-motion-easing-emphasized);
}
.md-tab:hover { color: var(--md-sys-color-on-surface); }
.md-tab.active { color: var(--md-sys-color-primary); }
.md-tab.active::after { transform: scaleX(1); }
.md-tab-panel { display: none; animation: fade-in var(--md-sys-motion-duration-medium2) var(--md-sys-motion-easing-emphasized-decelerate); }
.md-tab-panel.active { display: block; }

@media (max-width: 839px) {
  .md-showcase__grid { grid-template-columns: 1fr; gap: 40px; }
}

/* ---------- Timeline (流程) ---------- */
.md-timeline { position: relative; max-width: 900px; margin: 0 auto; }
.md-timeline::before {
  content: "";
  position: absolute;
  left: 24px; top: 0; bottom: 0;
  width: 2px;
  background-color: var(--md-sys-color-outline-variant);
}
.md-timeline__item {
  position: relative;
  padding-left: 72px;
  margin-bottom: 40px;
}
.md-timeline__dot {
  position: absolute;
  left: 0; top: 0;
  width: 48px; height: 48px;
  border-radius: var(--md-sys-shape-corner-full);
  background-color: var(--md-sys-color-primary-container);
  color: var(--md-sys-color-on-primary-container);
  display: flex; align-items: center; justify-content: center;
  font-size: var(--md-sys-typescale-title-medium-font);
  font-weight: var(--md-sys-typescale-title-medium-weight);
  z-index: 1;
}
.md-timeline__card {
  background-color: var(--md-sys-color-surface-container-low);
  border-radius: var(--md-comp-radius-surface);
  padding: 24px;
}
.md-timeline__card h4 { margin-bottom: 8px; }

@media (max-width: 599px) {
  .md-timeline::before { left: 16px; }
  .md-timeline__item { padding-left: 56px; }
  .md-timeline__dot { width: 40px; height: 40px; font-size: 14px; }
}

/* ---------- Pricing Cards ---------- */
.md-pricing__grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  align-items: stretch;
}
.md-pricing-card {
  position: relative;
  background-color: var(--md-sys-color-surface-container-low);
  border-radius: var(--md-comp-radius-surface);
  padding: 32px;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  transition: transform var(--md-sys-motion-duration-medium2) var(--md-sys-motion-easing-emphasized),
              box-shadow var(--md-sys-motion-duration-short3) var(--md-sys-motion-easing-standard);
}
.md-pricing-card:hover { transform: translateY(-6px); }
.md-pricing-card--featured {
  background-color: var(--md-sys-color-primary-container);
  color: var(--md-sys-color-on-primary-container);
  box-shadow: 0 2px 6px rgba(0,0,0,0.30), 0 4px 10px 3px rgba(0,0,0,0.15);
}
.md-pricing-card--featured .md-pricing__price { color: var(--md-sys-color-on-primary-container); }
.md-pricing-card__badge {
  position: absolute;
  top: 20px; right: 20px;
  padding: 4px 12px;
  border-radius: var(--md-sys-shape-corner-full);
  background-color: var(--md-sys-color-tertiary-container);
  color: var(--md-sys-color-on-tertiary-container);
  font-size: var(--md-sys-typescale-label-medium-font);
  font-weight: var(--md-sys-typescale-label-medium-weight);
}
.md-pricing__name { margin-bottom: 12px; }
.md-pricing__price { font-size: 40px; font-weight: 400; color: var(--md-sys-color-primary); margin-bottom: 8px; }
.md-pricing__desc { color: var(--md-sys-color-on-surface-variant); margin-bottom: 24px; }
.md-pricing-card--featured .md-pricing__desc { color: var(--md-sys-color-on-primary-container); opacity: 0.8; }
.md-pricing__features { flex: 1; margin-bottom: 32px; }
.md-pricing__features li {
  display: flex; align-items: center; gap: 12px;
  padding: 8px 0;
  color: var(--md-sys-color-on-surface-variant);
}
.md-pricing-card--featured .md-pricing__features li { color: var(--md-sys-color-on-primary-container); }
.md-pricing__features svg { width: 20px; height: 20px; color: var(--md-sys-color-primary); flex-shrink: 0; }
.md-pricing-card--featured .md-pricing__features svg { color: var(--md-sys-color-on-primary-container); }

@media (max-width: 839px) { .md-pricing__grid { grid-template-columns: 1fr; max-width: 420px; margin: 0 auto; } }

/* ---------- Testimonials ---------- */
.md-testimonials { background-color: var(--md-sys-color-surface-container-low); }
.md-testimonials__grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}
.md-quote {
  background-color: var(--md-sys-color-surface-container);
  border-radius: var(--md-comp-radius-surface);
  padding: 32px;
  display: flex;
  flex-direction: column;
}
.md-quote__mark { font-size: 56px; color: var(--md-sys-color-primary); line-height: 0.5; margin-bottom: 16px; }
.md-quote p { flex: 1; margin-bottom: 24px; }
.md-quote__author { display: flex; align-items: center; gap: 12px; }
.md-quote__avatar {
  width: 40px; height: 40px;
  border-radius: var(--md-sys-shape-corner-full);
  background-color: var(--md-sys-color-tertiary-container);
  color: var(--md-sys-color-on-tertiary-container);
  display: flex; align-items: center; justify-content: center;
  font-weight: 600;
}
@media (max-width: 839px) { .md-testimonials__grid { grid-template-columns: 1fr; } }

/* ---------- CTA ---------- */
.md-cta {
  text-align: center;
  padding: 96px 24px;
  border-radius: var(--md-sys-shape-corner-extra-large);
  background-color: var(--md-sys-color-primary-container);
  color: var(--md-sys-color-on-primary-container);
}
.md-cta h2 { margin-bottom: 16px; }
.md-cta p { font-size: var(--md-sys-typescale-headline-small-font); margin-bottom: 40px; opacity: 0.85; }
.md-cta .md-button--filled { background-color: var(--md-sys-color-primary); color: var(--md-sys-color-on-primary); }

/* ---------- Footer ---------- */
.md-footer {
  background-color: var(--md-sys-color-surface-container);
  padding: 64px 0 32px;
}
.md-footer__grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 40px;
  margin-bottom: 48px;
}
.md-footer__brand p { color: var(--md-sys-color-on-surface-variant); margin-top: 16px; max-width: 320px; }
.md-footer__col h5 { margin-bottom: 16px; }
.md-footer__col ul { display: flex; flex-direction: column; gap: 12px; }
.md-footer__col a {
  color: var(--md-sys-color-on-surface-variant);
  position: relative;
  overflow: hidden;
}
.md-footer__col a:hover { color: var(--md-sys-color-primary); }
.md-footer__bottom {
  padding-top: 32px;
  border-top: 1px solid var(--md-sys-color-outline-variant);
  display: flex;
  justify-content: space-between;
  align-items: center;
  color: var(--md-sys-color-on-surface-variant);
  font-size: var(--md-sys-typescale-body-small-font);
}
@media (max-width: 839px) { .md-footer__grid { grid-template-columns: 1fr 1fr; } }
@media (max-width: 599px) {
  .md-footer__grid { grid-template-columns: 1fr; }
  .md-footer__bottom { flex-direction: column; gap: 16px; text-align: center; }
}

/* ---------- 动效 ---------- */
@keyframes fade-up {
  from { opacity: 0; transform: translateY(24px); }
  to   { opacity: 1; transform: translateY(0); }
}
@keyframes fade-in {
  from { opacity: 0; }
  to   { opacity: 1; }
}

/* 滚动入场（由 JS 添加 .is-visible） */
.reveal {
  opacity: 0;
  transform: translateY(32px);
  transition: opacity var(--md-sys-motion-duration-medium4) var(--md-sys-motion-easing-emphasized-decelerate),
              transform var(--md-sys-motion-duration-medium4) var(--md-sys-motion-easing-emphasized-decelerate);
}
.reveal.is-visible { opacity: 1; transform: translateY(0); }