:root {
  --bg: #eee5d7;
  --card-bg: #f8f8f8;
  --text: #142849;
  --muted: #55657d;
  --border: #dfd4c7;
  --shadow: 0 28px 80px rgba(20, 40, 73, 0.08);
  --radius: 30px;
  --container: 1120px;
  --sticky-top: 54px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: "Inter", system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  color: var(--text);
  background:
    radial-gradient(circle at top left, rgba(255, 255, 255, 0.35), transparent 28%),
    linear-gradient(180deg, #efe7da 0%, #eadfce 100%);
}

img {
  max-width: 100%;
  display: block;
}

code {
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
  font-size: 0.92em;
}

.container {
  width: min(calc(100% - 48px), var(--container));
  margin-inline: auto;
}

.page-section {
  position: relative;
  overflow: visible;
}

.page-section--intro,
.page-section--outro {
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding: 96px 0;
}

.page-section--intro {
  background:
    radial-gradient(circle at 78% 24%, rgba(122, 60, 255, 0.15), transparent 28%),
    linear-gradient(135deg, #f8efe1 0%, #efe5d4 100%);
}

.page-section--outro {
  background:
    radial-gradient(circle at 22% 30%, rgba(90, 44, 255, 0.12), transparent 28%),
    linear-gradient(135deg, #e8decd 0%, #f5ecdd 100%);
}

.page-section--stack {
  padding: 96px 0 0;
  background:
    linear-gradient(180deg, rgba(255, 255, 255, 0.18), transparent 16%),
    linear-gradient(180deg, #efe7da 0%, #eadfce 100%);
}

.split-section {
  display: grid;
  grid-template-columns: minmax(0, 0.95fr) minmax(300px, 0.85fr);
  gap: clamp(32px, 6vw, 80px);
  align-items: center;
}

.split-section--reverse {
  grid-template-columns: minmax(300px, 0.85fr) minmax(0, 0.95fr);
}

.split-section--reverse .split-section__text {
  order: 2;
}

.split-section__text h1,
.split-section__text h2,
.section-heading h2 {
  margin: 0;
  font-size: clamp(2.4rem, 5vw, 5rem);
  line-height: 1.04;
  letter-spacing: -0.05em;
}

.split-section__text p,
.section-heading p {
  max-width: 720px;
  margin: 22px 0 0;
  font-size: clamp(1rem, 1.3vw, 1.18rem);
  line-height: 1.9;
  color: var(--muted);
}

.section-badge {
  display: inline-flex;
  align-items: center;
  margin-bottom: 18px;
  padding: 9px 15px;
  border-radius: 999px;
  border: 1px solid rgba(90, 44, 255, 0.14);
  background: rgba(255, 255, 255, 0.58);
  color: #6d35ff;
  font-size: 0.84rem;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

body.is-scrolled .section-badge {
  box-shadow: 0 6px 22px rgba(20, 40, 73, 0.08);
}

.section-heading {
  margin-bottom: 64px;
}

.section-heading h2 {
  max-width: 820px;
}

.intro-panel,
.outro-panel {
  position: relative;
  min-height: 430px;
  border-radius: 34px;
  border: 1px solid rgba(20, 40, 73, 0.1);
  background: rgba(255, 255, 255, 0.55);
  box-shadow: 0 30px 90px rgba(20, 40, 73, 0.08);
  overflow: hidden;
  backdrop-filter: blur(8px);
}

.intro-panel::before,
.outro-panel::before {
  content: "";
  position: absolute;
  inset: 0;
  background:
    linear-gradient(135deg, rgba(255, 255, 255, 0.82), transparent 38%),
    radial-gradient(circle at 76% 22%, rgba(122, 60, 255, 0.22), transparent 30%);
}

.intro-panel__line {
  position: absolute;
  left: 12%;
  height: 18px;
  border-radius: 999px;
  background: rgba(90, 44, 255, 0.2);
}

.intro-panel__line--wide {
  top: 28%;
  width: 54%;
}

.intro-panel__line:not(.intro-panel__line--wide) {
  top: 40%;
  width: 38%;
}

.intro-panel__grid {
  position: absolute;
  left: 12%;
  right: 12%;
  bottom: 15%;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
}

.intro-panel__grid span {
  aspect-ratio: 1;
  border-radius: 22px;
  background: linear-gradient(135deg, rgba(122, 60, 255, 0.28), rgba(255, 255, 255, 0.66));
}

.outro-panel__circle {
  position: absolute;
  width: 220px;
  aspect-ratio: 1;
  right: 12%;
  top: 16%;
  border-radius: 50%;
  background: linear-gradient(135deg, rgba(122, 60, 255, 0.25), rgba(255, 255, 255, 0.75));
}

.outro-panel__card {
  position: absolute;
  left: 13%;
  bottom: 20%;
  width: 62%;
  height: 136px;
  border-radius: 28px;
  background: rgba(255, 255, 255, 0.75);
  box-shadow: 0 20px 60px rgba(20, 40, 73, 0.1);
}

.outro-panel__card--small {
  left: 24%;
  bottom: 34%;
  width: 42%;
  height: 86px;
  background: rgba(122, 60, 255, 0.15);
}

.stack-section {
  /* 注意：这里不能设置 overflow: hidden，否则 sticky 容易被父级裁切或失效。 */
  overflow: visible;
}

.stack-list {
  position: relative;
  padding-bottom: 10vh;
}

.stack-card {
  position: sticky;
  top: calc(var(--sticky-top) + var(--stack-offset, 0px));
  z-index: var(--z, 10);
  margin-bottom: 90px;
}

.stack-card:last-of-type {
  margin-bottom: 0;
}

.stack-bottom-spacer {
  height: clamp(220px, 38vh, 420px);
}

.stack-card__content {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(320px, 476px);
  gap: clamp(24px, 4vw, 56px);
  align-items: center;
  min-height: 520px;
  padding: clamp(28px, 4vw, 42px);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: rgba(248, 248, 248, 0.96);
  box-shadow: var(--shadow);
  overflow: hidden;
  backdrop-filter: blur(6px);
}

.stack-card__content::before {
  content: "";
  position: absolute;
  inset: 0;
  background:
    linear-gradient(135deg, rgba(255, 255, 255, 0.65), transparent 42%),
    radial-gradient(circle at top right, color-mix(in srgb, var(--accent) 12%, transparent), transparent 25%);
  pointer-events: none;
}

.stack-card__content::after {
  content: "";
  position: absolute;
  left: 50%;
  top: 0;
  width: min(44%, 520px);
  height: 10px;
  transform: translateX(-4%);
  border-radius: 0 0 10px 10px;
  background: linear-gradient(90deg, color-mix(in srgb, var(--accent) 75%, white), var(--accent));
  opacity: 0.95;
}

.stack-card__text,
.stack-card__media {
  position: relative;
  z-index: 1;
}

.stack-card__tag {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 18px;
  padding: 8px 14px;
  border-radius: 999px;
  background: color-mix(in srgb, var(--accent) 10%, white);
  color: var(--accent);
  font-size: 0.84rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.stack-card__text h2 {
  margin: 0 0 18px;
  font-size: clamp(2rem, 3vw, 3rem);
  line-height: 1.05;
}

.stack-card__text p {
  margin: 0 0 22px;
  max-width: 560px;
  font-size: 1.06rem;
  line-height: 1.9;
  color: var(--muted);
}

.stack-card__points {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 12px;
}

.stack-card__points li {
  position: relative;
  padding-left: 24px;
  color: var(--text);
  line-height: 1.6;
}

.stack-card__points li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.72em;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  transform: translateY(-50%);
  background: var(--accent);
  box-shadow: 0 0 0 6px color-mix(in srgb, var(--accent) 14%, white);
}

.stack-card__media {
  padding-left: clamp(0px, 1vw, 8px);
}

.stack-card__media img {
  width: 100%;
  border-radius: 22px;
  border: 1px solid rgba(20, 40, 73, 0.08);
  box-shadow: 0 24px 60px rgba(20, 40, 73, 0.12);
}

@media (max-width: 991px) {
  :root {
    --sticky-top: 26px;
  }

  .page-section--intro,
  .page-section--outro {
    min-height: auto;
    padding: 72px 0;
  }

  .page-section--stack {
    padding-top: 72px;
  }

  .split-section,
  .split-section--reverse {
    grid-template-columns: 1fr;
  }

  .split-section--reverse .split-section__text {
    order: 0;
  }

  .intro-panel,
  .outro-panel {
    min-height: 320px;
  }

  .stack-card__content {
    grid-template-columns: 1fr;
    min-height: auto;
  }

  .stack-card__media {
    order: -1;
    padding-left: 0;
  }

  .stack-card__text h2 {
    font-size: clamp(1.7rem, 6vw, 2.4rem);
  }
}

@media (max-width: 640px) {
  .container {
    width: min(calc(100% - 24px), var(--container));
  }

  .page-section--intro,
  .page-section--outro {
    padding: 56px 0;
  }

  .page-section--stack {
    padding-top: 56px;
  }

  .section-heading {
    margin-bottom: 36px;
  }

  .split-section__text h1,
  .split-section__text h2,
  .section-heading h2 {
    font-size: clamp(2rem, 12vw, 3.2rem);
  }

  .intro-panel,
  .outro-panel {
    min-height: 260px;
    border-radius: 26px;
  }

  .stack-card {
    top: calc(var(--sticky-top) + var(--stack-offset-sm, var(--stack-offset, 0px)));
    margin-bottom: 48px;
  }

  .stack-card__content {
    padding: 20px;
    border-radius: 24px;
  }

  .stack-card__content::after {
    width: 56%;
    transform: translateX(-8%);
  }

  .stack-card__text p,
  .stack-card__points li {
    font-size: 0.96rem;
  }
}