@import url("https://fonts.googleapis.com/css2?family=DM+Serif+Display&family=IBM+Plex+Sans:wght@300;400;500;600&display=swap");
@import url("https://cdn.jsdelivr.net/npm/lxgw-wenkai-webfont@1.7.0/style.css");

@property --bg {
  syntax: "<color>";
  inherits: true;
  initial-value: #0f0f10;
}

@property --bg-accent {
  syntax: "<color>";
  inherits: true;
  initial-value: #161718;
}

@property --ink {
  syntax: "<color>";
  inherits: true;
  initial-value: #f2f2f2;
}

@property --muted {
  syntax: "<color>";
  inherits: true;
  initial-value: #a0a0a0;
}

@property --accent {
  syntax: "<color>";
  inherits: true;
  initial-value: #7ad6dc;
}

@property --accent-strong {
  syntax: "<color>";
  inherits: true;
  initial-value: #9ee8ec;
}

@property --card {
  syntax: "<color>";
  inherits: true;
  initial-value: #151516;
}

:root {
  color-scheme: light dark;
  --bg: #0f0f10;
  --bg-accent: #161718;
  --ink: #f2f2f2;
  --muted: #a0a0a0;
  --accent: #7ad6dc;
  --accent-strong: #9ee8ec;
  --card: #151516;
  --shadow: 0 24px 60px rgba(0, 0, 0, 0.45);
  --radius: 24px;
  transition:
    --bg 400ms ease,
    --bg-accent 400ms ease,
    --ink 400ms ease,
    --muted 400ms ease,
    --accent 400ms ease,
    --accent-strong 400ms ease,
    --card 400ms ease;
}

.mode-night {
  --bg: #0f0f10;
  --bg-accent: #17181a;
  --ink: #f1f1f2;
  --muted: #96979b;
  --accent: #8aa0ff;
  --accent-strong: #b7c2ff;
  --card: #151517;
  --shadow: 0 24px 60px rgba(0, 0, 0, 0.55);
}

.mode-moonlight {
  --bg: #0c1116;
  --bg-accent: #16212b;
  --ink: #eef4ff;
  --muted: #95a2b6;
  --accent: #8bd0ff;
  --accent-strong: #bfe8ff;
  --card: #131c24;
  --shadow: 0 24px 60px rgba(8, 12, 20, 0.6);
}

.mode-day {
  color-scheme: light;
  --bg: #f6f0e7;
  --bg-accent: #eadfce;
  --ink: #1c1b19;
  --muted: #5a5248;
  --accent: #3a6a6f;
  --accent-strong: #254a4d;
  --card: #fbf9f6;
  --shadow: 0 24px 60px rgba(28, 27, 25, 0.12);
}

.mode-sunny {
  color-scheme: light;
  --bg: #fff5dc;
  --bg-accent: #f6dfb1;
  --ink: #2b2418;
  --muted: #6b5b40;
  --accent: #d08a2e;
  --accent-strong: #a66512;
  --card: #fff9ee;
  --shadow: 0 24px 60px rgba(142, 101, 35, 0.2);
}

.mode-rainy {
  color-scheme: light;
  --bg: #e6eef2;
  --bg-accent: #cfdde6;
  --ink: #1b2a35;
  --muted: #50626e;
  --accent: #3b6b8a;
  --accent-strong: #2b4e66;
  --card: #f1f6f9;
  --shadow: 0 24px 60px rgba(33, 49, 60, 0.18);
}

.mode-snowy {
  color-scheme: light;
  --bg: #f3f6fb;
  --bg-accent: #e2ebf5;
  --ink: #1c2732;
  --muted: #5a6b7a;
  --accent: #5b8bc7;
  --accent-strong: #3f6fa8;
  --card: #f8fbff;
  --shadow: 0 24px 60px rgba(30, 44, 58, 0.12);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "IBM Plex Sans", system-ui, -apple-system, sans-serif;
  background: radial-gradient(circle at 20% 20%, color-mix(in srgb, var(--bg) 80%, #ffffff 20%) 0%, var(--bg) 45%, var(--bg-accent) 100%);
  color: var(--ink);
}

html[lang="zh-Hans"] body {
  font-family: "LXGW WenKai", "IBM Plex Sans", system-ui, -apple-system, sans-serif;
}

.page {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  position: relative;
  z-index: 2;
}

.shade-canvas {
  position: fixed;
  inset: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: 0;
  mix-blend-mode: multiply;
}

header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 32px 8vw 24px;
}

.brand {
  font-family: "DM Serif Display", serif;
  font-size: 28px;
  letter-spacing: 0.5px;
}

nav {
  display: flex;
  gap: 16px;
  align-items: center;
}

nav a {
  text-decoration: none;
  color: var(--ink);
  font-weight: 500;
}

.lang {
  display: inline-flex;
  gap: 8px;
  background: var(--card);
  padding: 6px;
  border-radius: 999px;
  box-shadow: var(--shadow);
}

.mode-switch {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 10px;
  border-radius: 999px;
  background: color-mix(in srgb, var(--card) 85%, transparent);
  border: 1px solid color-mix(in srgb, var(--ink) 12%, transparent);
  box-shadow: var(--shadow);
  letter-spacing: 0.4em;
  font-size: 12px;
  text-transform: uppercase;
}

.mode-switch button {
  background: transparent;
  border: none;
  color: var(--muted);
  cursor: pointer;
  font-weight: 600;
  padding: 2px 0;
  transition: color 0.2s ease, transform 0.2s ease;
}

.mode-switch button.active {
  color: var(--ink);
  transform: translateY(-1px);
}

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

.lang button {
  border: none;
  background: transparent;
  padding: 6px 12px;
  border-radius: 999px;
  font-weight: 500;
  color: var(--muted);
  cursor: pointer;
}

.lang button.active {
  background: var(--accent);
  color: #fff;
}

main {
  flex: 1;
  padding: 32px 8vw 80px;
  display: grid;
  gap: 64px;
}

.hero {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 32px;
  align-items: center;
}

.hero h1 {
  font-family: "DM Serif Display", serif;
  font-size: clamp(32px, 4vw, 56px);
  margin: 0 0 16px;
}

.hero p {
  font-size: 18px;
  color: var(--muted);
  line-height: 1.6;
  margin: 0 0 24px;
}

.cta {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.cta a {
  text-decoration: none;
  padding: 12px 20px;
  border-radius: 999px;
  font-weight: 600;
}

.cta a.primary {
  background: var(--accent);
  color: #fff;
}

.cta a.secondary {
  background: transparent;
  color: var(--accent-strong);
  border: 1px solid var(--accent-strong);
}

.features {
  display: grid;
  gap: 24px;
}

.story {
  display: grid;
  gap: 32px;
}

.story-header h2 {
  font-size: 28px;
  margin: 0 0 8px;
}

.story-header p {
  margin: 0;
  color: var(--muted);
  font-size: 18px;
}

.story-grid {
  display: grid;
  gap: 32px;
}

.story-item {
  display: grid;
  gap: 24px;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  align-items: center;
  background: var(--card);
  padding: 24px;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.story-item:nth-child(even) .story-media {
  order: 2;
}

.story-media img {
  width: 100%;
  height: auto;
  border-radius: 18px;
  display: block;
  box-shadow: 0 20px 40px rgba(0, 0, 0, 0.25);
}

.story-text h3 {
  margin: 0 0 8px;
  font-size: 22px;
}

.story-text p {
  margin: 0;
  color: var(--muted);
  line-height: 1.6;
}

.features h2,
.download h2 {
  font-size: 28px;
  margin: 0 0 12px;
}

.feature-grid {
  display: grid;
  gap: 16px;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
}

.feature {
  background: var(--card);
  padding: 24px;
  border-radius: 20px;
  box-shadow: var(--shadow);
}

.feature h3 {
  margin: 0 0 8px;
}

.feature p {
  margin: 0;
  color: var(--muted);
}

.assistant {
  background: var(--card);
  padding: 32px;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  display: grid;
  gap: 12px;
}

.assistant p {
  margin: 0;
  color: var(--muted);
}

.assistant-grid {
  display: grid;
  gap: 16px;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
}

.download {
  background: var(--card);
  padding: 32px;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  display: grid;
  gap: 12px;
}

.download a {
  width: fit-content;
}

footer {
  padding: 24px 8vw 40px;
  color: var(--muted);
  font-size: 14px;
}

.atmosphere {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 1;
  overflow: hidden;
}

.overlay {
  position: absolute;
  inset: 0;
  opacity: 0;
  transition: opacity 400ms ease;
}

.overlay-moonlight {
  background:
    radial-gradient(circle at 20% 15%, rgba(122, 208, 255, 0.22), transparent 45%),
    radial-gradient(circle at 70% 10%, rgba(255, 255, 255, 0.2), transparent 40%),
    radial-gradient(circle, rgba(255, 255, 255, 0.28) 1px, transparent 1px);
  background-size: 100% 100%, 100% 100%, 120px 120px;
  mix-blend-mode: screen;
  animation: twinkle 6s ease-in-out infinite;
}

.overlay-sunny {
  background:
    radial-gradient(circle at 20% 20%, rgba(255, 214, 140, 0.35), transparent 55%),
    radial-gradient(circle at 80% 10%, rgba(255, 237, 186, 0.28), transparent 60%),
    linear-gradient(120deg, rgba(255, 210, 120, 0.18), transparent 55%);
  animation: sway 7s ease-in-out infinite;
}

.overlay-rainy {
  background:
    repeating-linear-gradient(120deg, rgba(84, 110, 130, 0.18) 0 2px, transparent 2px 12px),
    radial-gradient(circle at 50% 15%, rgba(210, 226, 240, 0.4), transparent 55%);
  background-size: 180px 180px, 100% 100%;
  animation: rain 0.8s linear infinite;
  mix-blend-mode: multiply;
}

.overlay-rainy::after {
  content: "";
  position: absolute;
  inset: -20%;
  background: radial-gradient(circle at 50% 20%, rgba(170, 190, 205, 0.35), transparent 60%);
  filter: blur(24px);
  opacity: 0.7;
}

.overlay-snowy {
  background:
    radial-gradient(circle, rgba(255, 255, 255, 0.7) 1px, transparent 2px),
    radial-gradient(circle, rgba(255, 255, 255, 0.5) 1px, transparent 3px);
  background-size: 80px 80px, 140px 140px;
  animation: snow 8s linear infinite;
}

.mode-moonlight .overlay-moonlight,
.mode-sunny .overlay-sunny,
.mode-rainy .overlay-rainy,
.mode-snowy .overlay-snowy {
  opacity: 1;
}

@keyframes twinkle {
  0%,
  100% {
    opacity: 0.75;
  }
  50% {
    opacity: 1;
  }
}

@keyframes sway {
  0%,
  100% {
    transform: translateY(0);
  }
  50% {
    transform: translateY(12px);
  }
}

@keyframes rain {
  0% {
    background-position: 0 0, 0 0;
  }
  100% {
    background-position: 160px 240px, 0 0;
  }
}

@keyframes snow {
  0% {
    background-position: 0 0, 0 0;
  }
  100% {
    background-position: 0 200px, 0 320px;
  }
}

@media (max-width: 720px) {
  header {
    flex-direction: column;
    align-items: flex-start;
    gap: 16px;
  }

  nav {
    flex-wrap: wrap;
  }
}