/* ===== 设计令牌（对应 DESIGN.md，改这里前先改图纸） ===== */
:root {
  --bg-deepest: #070a12;
  --bg-base: #0b0f1a;
  --bg-raised: #131a2a;
  --flame: #ff6b35;
  --flame-rgb: 255, 107, 53;
  --ember: #ffc857;
  --text: #f5f0e8;
  --text-dim: rgba(245, 240, 232, 0.6);
  --ease-reveal: cubic-bezier(0.16, 1, 0.3, 1);

  /* 8 倍数间距体系 */
  --s-4: 4px;
  --s-8: 8px;
  --s-12: 12px;
  --s-16: 16px;
  --s-24: 24px;
  --s-32: 32px;
  --s-48: 48px;
  --s-64: 64px;
  --s-96: 96px;
  --s-128: 128px;

  /* 字号四级梯度 */
  --fs-hero: clamp(40px, 8vw, 80px);
  --fs-title: clamp(24px, 4vw, 32px);
  --fs-body: 17px;
  --fs-note: 13px;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  background: var(--bg-deepest);
  color: var(--text);
  font-family: "PingFang SC", "HarmonyOS Sans SC", "Source Han Sans SC", system-ui, sans-serif;
  font-size: var(--fs-body);
  line-height: 1.8;
}

body > .hero,
body > main {
  position: relative;
  z-index: 2;
}

/* ===== 硬分页：有 JS 时任意时刻只显示当前页 ===== */
.js body {
  height: 100vh;
  height: 100dvh;
  overflow: hidden;
}

.js .page {
  display: none;
  position: fixed;
  inset: 0;
  width: 100%;
}

.js .hero.active-page { display: block; }

.js .section.active-page {
  display: flex;
  animation: pageEnter 0.65s var(--ease-reveal) both;
}

@keyframes pageEnter {
  from { opacity: 0; transform: translateY(24px); }
  to { opacity: 1; transform: translateY(0); }
}

/* ===== 全页星空 ===== */
#starfield {
  position: fixed;
  inset: 0;
  width: 100%;
  height: 100%;
  z-index: 0;
  pointer-events: none;
}

/* ===== 光标余光（仅桌面，JS 挂 active） ===== */
.cursor-glow {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 1;
  background: radial-gradient(
    600px circle at var(--mouse-x, 50%) var(--mouse-y, 50%),
    rgba(var(--flame-rgb), 0.05),
    transparent 40%
  );
  opacity: 0;
  transition: opacity 0.3s ease;
}

.cursor-glow.active { opacity: 1; }

/* ===== 左侧圆点导航 ===== */
.page-nav {
  position: fixed;
  left: 28px;
  top: 50%;
  transform: translateY(-50%);
  z-index: 50;
  display: flex;
  flex-direction: column;
  gap: 20px;
}

/* 火色游标：位置与形变由 JS 写 CSS 变量 */
.page-nav::before {
  content: "";
  position: absolute;
  left: calc((8px - var(--dot-w, 8px)) / 2);
  top: var(--dot-top, 0px);
  width: var(--dot-w, 8px);
  height: var(--dot-height, 8px);
  border-radius: var(--dot-br, 50%);
  background: rgba(var(--flame-rgb), 0.6);
  box-shadow: 0 0 6px rgba(var(--flame-rgb), 0.3);
  transition: top 0.45s var(--ease-reveal);
  pointer-events: none;
}

.page-dot {
  position: relative;
  display: block;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: rgba(245, 240, 232, 0.15);
}

.page-dot span {
  position: absolute;
  left: 20px;
  top: 50%;
  transform: translateY(-50%);
  font-size: 12px;
  color: var(--text-dim);
  white-space: nowrap;
  opacity: 0;
  transition: opacity 0.3s;
  pointer-events: none;
}

.page-dot:hover span,
.page-dot:focus-visible span { opacity: 1; }

.page-dot:focus-visible {
  outline: 2px solid rgba(var(--flame-rgb), 0.6);
  outline-offset: 4px;
}

.page-dot.active span { color: var(--ember); }

/* ===== 首屏 ===== */
.hero {
  position: relative;
  height: 100vh;
  height: 100dvh;
  overflow: hidden;
}

.hero canvas {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
}

/* 火在上（canvas 焰心约 40% 高度处），文字在下 */
.hero-text {
  position: absolute;
  left: 50%;
  top: 64%;
  transform: translateX(-50%);
  width: 100%;
  text-align: center;
  padding: 0 var(--s-24);
}

.hero h1 {
  font-size: var(--fs-hero);
  font-weight: 600;
  letter-spacing: 0.04em;
  line-height: 1.3;
}

.hero .hero-sub {
  margin-top: var(--s-24);
  color: var(--text-dim);
}

.hero-tags {
  margin-top: var(--s-24);
  display: flex;
  justify-content: center;
  gap: var(--s-12);
  flex-wrap: wrap;
}

.hero-tags span {
  padding: var(--s-4) var(--s-16);
  font-size: var(--fs-note);
  color: var(--text-dim);
  border: 1px solid rgba(245, 240, 232, 0.15);
  border-radius: 999px;
}

/* 标语入场：每次回到首页都按顺序重播 */
.js .hero-text > * {
  opacity: 0;
  animation: none;
}

.js .hero.active-page .hero-text > * { animation: heroFadeUp 1s ease-out both; }
.js .hero.active-page .hero-text h1 { animation-delay: 0.2s; }
.js .hero.active-page .hero-text .hero-sub { animation-delay: 0.7s; }
.js .hero.active-page .hero-text .hero-tags { animation-delay: 1.2s; }

@keyframes heroFadeUp {
  from { opacity: 0; transform: translateY(16px); }
  to { opacity: 1; transform: translateY(0); }
}

/* scroll hint（放左下，避开中央文字列） */
.scroll-hint {
  position: absolute;
  bottom: 28%;
  left: 8%;
  padding: var(--s-12);
  cursor: pointer;
}

.js .scroll-hint {
  opacity: 0;
  animation: none;
}

.js .hero.active-page .scroll-hint { animation: heroFadeUp 1s ease-out 1.9s both; }

.scroll-arrow {
  display: block;
  width: 16px;
  height: 16px;
  border-right: 2px solid var(--flame);
  border-bottom: 2px solid var(--ember);
  transform: rotate(45deg);
  animation: scrollBounce 2s ease-in-out infinite;
}

@keyframes scrollBounce {
  0%, 100% { transform: rotate(45deg) translateY(0); opacity: 0.6; }
  50% { transform: rotate(45deg) translateY(8px); opacity: 1; }
}

/* ===== 内容板块 ===== */
.section {
  max-width: 720px;
  height: 100vh;
  height: 100dvh;
  margin: 0 auto;
  padding: var(--s-48) var(--s-24);
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  justify-content: safe center;
}

.section-wide { max-width: 1080px; }

.section h2 {
  font-size: var(--fs-title);
  font-weight: 600;
}

/* ===== 滚动点亮（仅 JS 启用；无 JS 直出） ===== */
.js .reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.85s var(--ease-reveal), transform 0.85s var(--ease-reveal);
}

.js .reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ===== 我的故事：时间线逐节点亮 ===== */
.timeline {
  list-style: none;
  margin-top: var(--s-32);
  padding-left: var(--s-24);
  border-left: 1px solid rgba(245, 240, 232, 0.15);
  display: flex;
  flex-direction: column;
  gap: var(--s-24);
}

.timeline li {
  position: relative;
}

/* 无 JS：直出且点亮 */
.timeline li::before {
  content: "";
  position: absolute;
  left: calc(-1 * var(--s-24) - 4px);
  top: 12px;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--flame);
  box-shadow: 0 0 8px rgba(var(--flame-rgb), 0.6);
}

/* 有 JS：先暗藏，逐节点亮 */
.js .timeline li {
  opacity: 0;
  transform: translateY(12px);
  transition: opacity 0.7s var(--ease-reveal), transform 0.7s var(--ease-reveal);
}

.js .timeline li::before {
  background: rgba(var(--flame-rgb), 0.25);
  box-shadow: none;
  transition: background 0.4s, box-shadow 0.4s;
}

.js .timeline li.lit {
  opacity: 1;
  transform: translateY(0);
}

.js .timeline li.lit::before {
  background: var(--flame);
  box-shadow: 0 0 8px rgba(var(--flame-rgb), 0.6);
}

.timeline .year {
  color: var(--flame);
  font-weight: 600;
  margin-right: var(--s-16);
}

.stats {
  display: flex;
  gap: var(--s-48);
  margin-top: var(--s-48);
  flex-wrap: wrap;
}

.stats strong {
  display: block;
  font-size: var(--fs-title);
  font-weight: 600;
  color: var(--ember);
}

.stats span {
  font-size: var(--fs-note);
  color: var(--text-dim);
}

.story-line {
  margin-top: var(--s-48);
  color: var(--text-dim);
}

/* ===== 卡片区 ===== */
.cards {
  margin-top: var(--s-32);
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: var(--s-24);
}

.card {
  background: var(--bg-raised);
  border: 1px solid rgba(245, 240, 232, 0.08);
  border-radius: 12px;
  padding: var(--s-24);
  transition: border-color 0.3s, transform 0.3s;
}

.card:hover {
  border-color: rgba(255, 200, 87, 0.35);
  transform: translateY(-2px);
}

.card h3 {
  font-size: var(--fs-body);
  font-weight: 600;
}

.card p {
  margin-top: var(--s-8);
  font-size: var(--fs-note);
  color: var(--text-dim);
}

.join-line {
  margin-top: var(--s-16);
  color: var(--text-dim);
}

footer {
  margin-top: var(--s-64);
  padding: var(--s-24);
  text-align: center;
  font-size: var(--fs-note);
  color: var(--text-dim);
}

/* ===== 矮视口：收缩首屏，防止标签行溢出 ===== */
@media (max-height: 936px) {
  .hero-text { top: 60%; }
}

@media (max-height: 860px) {
  .hero h1 { font-size: clamp(40px, 6vw, 64px); }
}

/* ===== 手机端 ===== */
@media (max-width: 768px) {
  .page-nav,
  .cursor-glow,
  .scroll-hint { display: none; }

  .section { padding: var(--s-32) var(--s-16); }

  .cards {
    margin-top: var(--s-24);
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: var(--s-12);
  }

  .card { padding: var(--s-16); }
}

/* ===== 弱动效偏好：全部直接显示 ===== */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .js .page.active-page { animation: none; }
  .js .hero.active-page .hero-text > *,
  .js .hero.active-page .scroll-hint { animation: none; opacity: 1; }
  .scroll-arrow { animation: none; }
  .js .reveal,
  .js .timeline li {
    opacity: 1;
    transform: none;
    transition: none;
  }
  .js .timeline li::before {
    background: var(--flame);
  }
}