:root {
  --background: #000000;
  --surface: #0a0a0a;
  --surface-active: #121212;
  --text: #f5f5f5;
  --muted: #8a8a8a;
  --faint: #565656;
  --border: #1c1c1c;
  --border-strong: #2e2e2e;
  --accent: #ffffff;
  --accent-ink: #000000;
  --header-height: 72px;
  --page-gutter: clamp(24px, 4vw, 64px);
  --card-width: clamp(272px, 22vw, 336px);
  --card-height: clamp(252px, 20vw, 296px);
  --card-gap: clamp(12px, 1vw, 18px);
  --fx-mid: clamp(150px, 30vh, 300px);
  color-scheme: dark;
  font-family:
    Inter, ui-sans-serif, -apple-system, BlinkMacSystemFont, "SF Pro Display",
    "PingFang SC", "Microsoft YaHei", sans-serif;
  font-synthesis: none;
  text-rendering: optimizeLegibility;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-width: 320px;
  min-height: 100vh;
  overflow-x: hidden;
  background: var(--background);
  color: var(--text);
  -webkit-font-smoothing: antialiased;
}

::selection {
  color: var(--accent-ink);
  background: var(--accent);
}

button,
a {
  -webkit-tap-highlight-color: transparent;
}

button {
  font: inherit;
}

a {
  color: inherit;
  text-decoration: none;
}

svg {
  display: block;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
  border: 0;
}

.skip-link {
  position: fixed;
  top: 10px;
  left: 10px;
  z-index: 30;
  padding: 10px 16px;
  color: var(--accent-ink);
  background: var(--accent);
  border-radius: 999px;
  transform: translateY(-160%);
  transition: transform 180ms ease;
}

.skip-link:focus {
  transform: translateY(0);
}

.site-header {
  position: relative;
  z-index: 5;
  display: flex;
  height: var(--header-height);
  padding: 0 var(--page-gutter);
  align-items: center;
  justify-content: space-between;
  background: rgba(0, 0, 0, 0.72);
  border-bottom: 1px solid #141414;
  backdrop-filter: saturate(1.2) blur(12px);
}

.brand {
  font-size: clamp(19px, 1.7vw, 24px);
  font-weight: 680;
  letter-spacing: -0.03em;
}

.site-nav {
  display: flex;
  height: 100%;
  gap: clamp(28px, 3.5vw, 52px);
  align-items: center;
}

.site-nav a {
  position: relative;
  display: grid;
  height: 100%;
  align-items: center;
  color: var(--muted);
  font-size: 15px;
  font-weight: 500;
  letter-spacing: 0.01em;
  transition: color 180ms ease;
}

.site-nav a:hover,
.site-nav a:focus-visible,
.site-nav a.is-current {
  color: var(--text);
}

.site-nav a.is-current::after {
  position: absolute;
  right: 0;
  bottom: -1px;
  left: 0;
  height: 2px;
  background: var(--accent);
  content: "";
}

/* ---------- Hero：纯黑 + 光影 ---------- */

.hero {
  position: relative;
  display: flex;
  min-height: clamp(660px, 92vh, 960px);
  padding: 0 var(--page-gutter) clamp(64px, 9vh, 104px);
  flex-direction: column;
  justify-content: flex-end;
  overflow: hidden;
  text-align: center;
}

.hero-fx {
  position: absolute;
  inset: 0;
  z-index: 1;
  pointer-events: none;
  opacity: 0;
}

.is-ready .hero-fx {
  opacity: 1;
  transition: opacity 1.4s ease 100ms;
}

.fx-halo {
  position: absolute;
  top: var(--fx-mid);
  left: 50%;
  width: min(1100px, 150vw);
  height: min(1100px, 150vw);
  background: radial-gradient(
    circle,
    rgba(255, 255, 255, 0.18) 0%,
    rgba(255, 255, 255, 0.06) 34%,
    transparent 62%
  );
  transform: translate(-50%, -50%);
}

.fx-crescent {
  position: absolute;
  top: var(--fx-mid);
  left: 50%;
  width: clamp(150px, 17vw, 230px);
  height: clamp(150px, 17vw, 230px);
  border-radius: 50%;
  background: radial-gradient(
    circle at 50% 116%,
    rgba(255, 255, 255, 0.9) 0%,
    rgba(255, 255, 255, 0.5) 12%,
    rgba(255, 255, 255, 0.18) 30%,
    rgba(255, 255, 255, 0.05) 48%,
    transparent 62%
  );
  filter: blur(1.5px);
  transform: translate(-50%, -50%);
  animation: crescent-breathe 6s ease-in-out infinite;
}

.fx-crescent::before {
  position: absolute;
  inset: -32%;
  border-radius: 50%;
  background: radial-gradient(
    circle at 50% 120%,
    rgba(255, 255, 255, 0.5) 0%,
    rgba(255, 255, 255, 0.16) 32%,
    transparent 60%
  );
  filter: blur(34px);
  content: "";
}

.fx-beam {
  position: absolute;
  top: var(--fx-mid);
  left: 50%;
  width: min(780px, 88vw);
  height: clamp(240px, 34vh, 360px);
  background: conic-gradient(
    from 180deg at 50% 0%,
    transparent 46.5%,
    rgba(255, 255, 255, 0.11) 50%,
    transparent 53.5%
  );
  filter: blur(8px);
  transform: translateX(-50%);
}

.fx-stars {
  position: absolute;
  top: calc(var(--fx-mid) - 40px);
  left: 50%;
  width: 2px;
  height: 2px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.85);
  box-shadow:
    -19vw -8vh 0 0 rgba(255, 255, 255, 0.5),
    -13vw 4vh 0 0 rgba(255, 255, 255, 0.35),
    -26vw 2vh 0 0 rgba(255, 255, 255, 0.28),
    16vw -9vh 0 0 rgba(255, 255, 255, 0.55),
    23vw 3vh 0 0 rgba(255, 255, 255, 0.32),
    9vw -5vh 0 0 rgba(255, 255, 255, 0.42),
    -7vw -11vh 0 0 rgba(255, 255, 255, 0.3);
  animation: twinkle 4.5s ease-in-out infinite alternate;
}

.hero-copy {
  position: relative;
  z-index: 2;
  max-width: 880px;
  margin: 0 auto;
  opacity: 0;
  transform: translateY(18px);
}

.is-ready .hero-copy {
  opacity: 1;
  transform: translateY(0);
  transition:
    opacity 700ms cubic-bezier(0.16, 1, 0.3, 1),
    transform 900ms cubic-bezier(0.16, 1, 0.3, 1);
}

.hero h1 {
  max-width: 880px;
  margin: 0;
  font-size: clamp(42px, 5.4vw, 80px);
  font-weight: 640;
  letter-spacing: -0.045em;
  line-height: 1.18;
  text-wrap: balance;
}

.hero-copy > p {
  max-width: 560px;
  margin: clamp(20px, 3vh, 28px) auto 0;
  color: var(--muted);
  font-size: clamp(16px, 1.5vw, 20px);
  font-weight: 400;
  letter-spacing: 0.02em;
  line-height: 1.7;
}

.hero-actions {
  display: flex;
  margin-top: clamp(30px, 4.5vh, 44px);
  align-items: center;
  flex-wrap: wrap;
  gap: 14px;
  justify-content: center;
}

.primary-action {
  display: inline-flex;
  height: 50px;
  padding: 0 28px;
  align-items: center;
  gap: 12px;
  justify-content: center;
  color: #ededed;
  background: transparent;
  border: 1px solid #363636;
  border-radius: 999px;
  font-size: 15px;
  font-weight: 560;
  letter-spacing: 0.02em;
  transition:
    color 220ms ease,
    background 220ms ease,
    border-color 220ms ease,
    transform 220ms ease;
}

.primary-action svg {
  width: 19px;
  fill: none;
  stroke: currentColor;
  stroke-linecap: round;
  stroke-linejoin: round;
  stroke-width: 1.7;
  transition: transform 220ms ease;
}

.primary-action:hover,
.primary-action:focus-visible {
  color: var(--accent);
  background: #101010;
  border-color: #9a9a9a;
  transform: translateY(-1px);
}

.primary-action:hover svg,
.primary-action:focus-visible svg {
  transform: translateX(4px);
}

/* ---------- 工具 ---------- */

.tools {
  position: relative;
  z-index: 4;
  padding: clamp(56px, 8vh, 88px) 0 8px;
  border-top: 1px solid #141414;
}

.section-head {
  width: min(1280px, calc(100% - var(--page-gutter) * 2));
  margin: 0 auto clamp(30px, 4.5vh, 44px);
}

.section-head h2 {
  margin: 0;
  font-size: clamp(30px, 3.2vw, 44px);
  font-weight: 640;
  letter-spacing: -0.035em;
  line-height: 1.2;
}

.section-head p {
  margin: 12px 0 0;
  color: #777777;
  font-size: clamp(15px, 1.3vw, 18px);
  font-weight: 400;
  letter-spacing: 0.02em;
}

.carousel {
  width: 100%;
}

.carousel-viewport {
  width: 100%;
  padding: 18px 0 20px;
  overflow: hidden;
  cursor: grab;
  touch-action: pan-y;
}

.carousel-viewport:active {
  cursor: grabbing;
}

.module-track {
  display: flex;
  width: max-content;
  column-gap: var(--card-gap);
  will-change: transform;
}

.module-track.is-animated {
  transition: transform 720ms cubic-bezier(0.2, 0.76, 0.22, 1);
}

.module-card {
  position: relative;
  display: flex;
  width: var(--card-width);
  height: var(--card-height);
  flex: 0 0 var(--card-width);
  padding: clamp(24px, 2.15vw, 32px);
  flex-direction: column;
  justify-content: space-between;
  overflow: hidden;
  color: var(--text);
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 20px;
  opacity: 0.6;
  transform: scale(0.94);
  transition:
    opacity 500ms ease,
    transform 720ms cubic-bezier(0.2, 0.76, 0.22, 1),
    border-color 420ms ease,
    box-shadow 420ms ease;
  user-select: none;
}

.module-card.is-active {
  z-index: 2;
  border-color: rgba(255, 255, 255, 0.85);
  box-shadow:
    0 24px 70px rgba(0, 0, 0, 0.6),
    0 0 36px rgba(255, 255, 255, 0.06);
  opacity: 1;
  outline: none;
  transform: scale(1);
}

.module-card.is-active:focus-visible {
  box-shadow:
    0 0 0 3px rgba(255, 255, 255, 0.18),
    0 24px 70px rgba(0, 0, 0, 0.6);
}

.module-card-top {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
}

.module-icon {
  display: grid;
  width: 54px;
  height: 54px;
  place-items: center;
  color: #cfcfcf;
  background: #141414;
  border: 1px solid #242424;
  border-radius: 15px;
  transition:
    color 320ms ease,
    background 320ms ease,
    border-color 320ms ease;
}

.module-icon svg {
  width: 28px;
  height: 28px;
  fill: none;
  stroke: currentColor;
  stroke-linecap: round;
  stroke-linejoin: round;
  stroke-width: 1.4;
}

.module-card.is-active .module-icon {
  color: var(--accent-ink);
  background: var(--accent);
  border-color: var(--accent);
}

.module-number {
  color: #333333;
  font-family: "SF Pro Display", Inter, sans-serif;
  font-size: clamp(30px, 2.8vw, 42px);
  font-weight: 300;
  letter-spacing: -0.04em;
  line-height: 1;
  transition: color 320ms ease;
}

.module-card.is-active .module-number {
  color: var(--text);
}

.module-copy {
  margin-top: auto;
  padding-top: 26px;
}

.module-copy h3 {
  margin: 0;
  font-size: clamp(22px, 1.9vw, 28px);
  font-weight: 600;
  letter-spacing: -0.03em;
  line-height: 1.25;
}

.module-copy p {
  margin: 10px 0 0;
  color: var(--muted);
  font-size: clamp(14px, 1.05vw, 16px);
  font-weight: 400;
  letter-spacing: 0.02em;
  line-height: 1.55;
}

.module-open {
  position: absolute;
  right: clamp(20px, 2vw, 28px);
  bottom: clamp(18px, 1.8vw, 26px);
  display: grid;
  width: 36px;
  height: 36px;
  padding: 0;
  place-items: center;
  color: #777777;
  background: transparent;
  border: 1px solid #262626;
  border-radius: 50%;
  pointer-events: none;
  transition:
    color 220ms ease,
    background 220ms ease,
    border-color 220ms ease,
    transform 220ms ease;
}

.module-open svg {
  width: 19px;
  fill: none;
  stroke: currentColor;
  stroke-linecap: round;
  stroke-linejoin: round;
  stroke-width: 1.5;
}

.module-card.is-active .module-open {
  color: var(--accent-ink);
  background: var(--accent);
  border-color: var(--accent);
}

.module-card.is-active:hover .module-open {
  transform: translateX(3px);
}

.carousel-controls {
  display: grid;
  width: min(1280px, calc(100% - var(--page-gutter) * 2));
  margin: 14px auto 0;
  grid-template-columns: 42px minmax(0, 1fr) 42px;
  gap: clamp(24px, 4vw, 58px);
  align-items: start;
}

.round-control {
  display: grid;
  width: 42px;
  height: 42px;
  padding: 0;
  place-items: center;
  color: #8a8a8a;
  background: transparent;
  border: 1px solid #222222;
  border-radius: 50%;
  cursor: pointer;
  transition:
    color 180ms ease,
    background 180ms ease,
    border-color 180ms ease;
}

.round-control:hover,
.round-control:focus-visible {
  color: var(--accent);
  background: #0d0d0d;
  border-color: #e5e5e5;
  outline: none;
}

.round-control svg {
  width: 20px;
  fill: none;
  stroke: currentColor;
  stroke-linecap: round;
  stroke-linejoin: round;
  stroke-width: 1.5;
}

.progress {
  position: relative;
  display: grid;
  grid-template-columns: repeat(var(--module-count, 6), 1fr);
}

.progress::before {
  position: absolute;
  top: 10px;
  right: 8.33%;
  left: 8.33%;
  height: 1px;
  background: var(--border);
  content: "";
}

.progress-stop {
  position: relative;
  z-index: 1;
  display: flex;
  padding: 0;
  align-items: center;
  flex-direction: column;
  color: #666666;
  background: transparent;
  border: 0;
  cursor: pointer;
  font-family: "SF Pro Display", Inter, sans-serif;
  font-size: 15px;
  font-weight: 400;
  transition: color 260ms ease;
}

.progress-stop::before {
  width: 15px;
  height: 15px;
  margin: 3px 0 9px;
  background: var(--background);
  border: 1px solid #333333;
  border-radius: 50%;
  content: "";
  transition:
    background 360ms ease,
    border-color 360ms ease,
    box-shadow 360ms ease,
    transform 360ms ease;
}

.progress-stop:hover,
.progress-stop:focus-visible,
.progress-stop.is-current {
  color: var(--accent);
  outline: none;
}

.progress-stop.is-current::before {
  background: var(--accent);
  border-color: var(--accent);
  box-shadow: 0 0 0 5px rgba(255, 255, 255, 0.08);
  transform: scale(1.06);
}

.site-footer {
  display: flex;
  min-height: 96px;
  margin-top: clamp(48px, 7vh, 80px);
  padding: 26px var(--page-gutter) 30px;
  align-items: center;
  justify-content: center;
  color: #555555;
  border-top: 1px solid #141414;
  font-size: 13px;
  font-weight: 450;
  letter-spacing: 0.1em;
}

.module-notice {
  position: fixed;
  right: 24px;
  bottom: 24px;
  z-index: 20;
  max-width: calc(100% - 48px);
  padding: 13px 22px;
  color: var(--accent-ink);
  background: var(--accent);
  border-radius: 999px;
  box-shadow: 0 18px 48px rgba(0, 0, 0, 0.55);
  font-size: 14px;
  font-weight: 550;
  letter-spacing: 0.01em;
  opacity: 0;
  pointer-events: none;
  transform: translateY(12px);
  transition:
    opacity 220ms ease,
    transform 280ms cubic-bezier(0.16, 1, 0.3, 1);
}

.module-notice.is-visible {
  opacity: 1;
  transform: translateY(0);
}

@keyframes crescent-breathe {
  0%,
  100% {
    opacity: 0.92;
    transform: translate(-50%, -50%) scale(1);
  }
  50% {
    opacity: 1;
    transform: translate(-50%, -50%) scale(1.03);
  }
}

@keyframes twinkle {
  0% {
    opacity: 0.35;
  }
  100% {
    opacity: 0.75;
  }
}

@media (max-width: 1080px) {
  :root {
    --card-width: 300px;
    --card-height: 272px;
  }

  .hero h1 {
    font-size: clamp(40px, 6vw, 68px);
  }
}

@media (max-width: 760px) {
  :root {
    --header-height: 64px;
    --page-gutter: 20px;
    --card-width: min(82vw, 340px);
    --card-height: 284px;
    --card-gap: 12px;
    --fx-mid: clamp(120px, 22vh, 190px);
  }

  .brand {
    font-size: 20px;
  }

  .site-nav {
    gap: 24px;
  }

  .site-nav a {
    font-size: 13px;
  }

  .hero {
    min-height: 620px;
    padding-bottom: 56px;
  }

  .hero h1 {
    font-size: clamp(37px, 10.5vw, 54px);
    letter-spacing: -0.04em;
    line-height: 1.22;
  }

  .hero-copy > p {
    max-width: 22em;
    margin-top: 18px;
    font-size: 15px;
    line-height: 1.7;
  }

  .hero-actions {
    margin-top: 28px;
  }

  .primary-action {
    height: 48px;
    padding: 0 24px;
    font-size: 14px;
  }

  .tools {
    padding-top: 52px;
  }

  .section-head {
    margin-bottom: 26px;
  }

  .carousel-viewport {
    padding: 14px 0 14px;
  }

  .module-card {
    padding: 26px;
    opacity: 0.38;
    transform: scale(0.92);
  }

  .module-card.is-active {
    transform: scale(1);
  }

  .module-copy h3 {
    font-size: 26px;
  }

  .module-copy p {
    padding-right: 26px;
    font-size: 15px;
  }

  .carousel-controls {
    width: calc(100% - 32px);
    margin-top: 8px;
    grid-template-columns: 38px minmax(0, 1fr) 38px;
    gap: 12px;
  }

  .round-control {
    width: 38px;
    height: 38px;
  }

  .progress-stop span {
    display: none;
  }

  .progress-stop::before {
    width: 12px;
    height: 12px;
    margin-top: 4px;
  }

  .progress::before {
    top: 10px;
  }

  .site-footer {
    min-height: 84px;
    margin-top: 44px;
    padding-bottom: 26px;
    font-size: 11px;
  }

  .module-notice {
    right: 16px;
    bottom: 16px;
    max-width: calc(100% - 32px);
  }
}

@media (max-width: 420px) {
  .site-nav a:first-child {
    display: none;
  }

  .hero h1 {
    font-size: 36px;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}