/* ============================================================
   四季官网 · 共享样式 /assets/site.css
   1 基础重置 / 2 变量 / 3 中文排版 / 4 通用组件 / 5 头部 / 6 页脚 / 7 响应式与偏好
   ============================================================ */

/* ---------- 1 基础重置 ---------- */
*,
*::before,
*::after { box-sizing: border-box; }

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

body,
h1, h2, h3, h4, h5,
p, ul, ol, li,
figure, blockquote, dl, dd {
  margin: 0;
  padding: 0;
}

ul, ol { list-style: none; }

button {
  font: inherit;
  color: inherit;
  background: none;
  border: 0;
  cursor: pointer;
}

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

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

[hidden] { display: none !important; }

/* ---------- 2 变量 ---------- */
:root {
  --paper: #F7F3EA;
  --paper-warm: #EFE6D6;
  --ink: #16302A;
  --ink-deep: #0D1512;
  --spring: #E8A7B5;
  --summer: #6EA6BE;
  --autumn: #DFA057;
  --winter: #3E6A55;
  --mist: #79897F;
  --vermilion: #C24A31;

  --season: var(--spring);
  --scroll-progress: 0%;

  --rail-w: 88px;
  --radius-card: 24px;
  --radius-pill: 999px;

  --space-1: 24px;
  --space-2: 48px;
  --space-3: 88px;
  --space-4: 132px;

  --font-heading: 'Noto Serif SC', 'Source Han Serif SC', 'Songti SC', 'STSong', serif;
  --font-body: 'Noto Sans SC', 'PingFang SC', 'Microsoft YaHei', system-ui, -apple-system, sans-serif;
  --font-mono: 'IBM Plex Mono', 'JetBrains Mono', ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;

  --ease-soft: cubic-bezier(0.2, 0.6, 0.2, 1);
}

html[data-season="spring"] { --season: var(--spring); }
html[data-season="summer"] { --season: var(--summer); }
html[data-season="autumn"] { --season: var(--autumn); }
html[data-season="winter"] { --season: var(--winter); }

/* ---------- 3 中文排版 ---------- */
body {
  min-height: 100vh;
  font-family: var(--font-body);
  font-size: 17px;
  line-height: 1.85;
  color: var(--ink);
  background-color: var(--paper);
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: 2;
  pointer-events: none;
  opacity: 0.035;
  background-image: radial-gradient(var(--ink-deep) 0.5px, transparent 0.5px);
  background-size: 4px 4px;
}

h1, h2, h3, h4 {
  font-family: var(--font-heading);
  font-weight: 700;
  line-height: 1.28;
  letter-spacing: -0.01em;
  color: var(--ink-deep);
}

h1 { font-size: clamp(40px, 6vw, 64px); line-height: 1.14; }
h2 { font-size: clamp(26px, 3vw, 34px); }
h3 { font-size: 20px; font-weight: 500; line-height: 1.5; }

p + p { margin-top: 1.2em; }

a:focus-visible,
button:focus-visible,
[tabindex]:focus-visible {
  outline: 2px solid var(--winter);
  outline-offset: 3px;
  border-radius: 6px;
}

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

/* ---------- 4 通用组件 ---------- */
.wrap {
  width: 100%;
  max-width: 1280px;
  margin-inline: auto;
  padding-inline: clamp(20px, 4.4vw, 56px);
}

.site-main {
  display: block;
  padding-top: clamp(84px, 9vw, 112px);
  padding-bottom: clamp(64px, 8vw, 112px);
}

hr {
  border: 0;
  border-top: 1px dashed rgba(22, 48, 42, 0.22);
  margin: var(--space-2) 0;
}

.index-label {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--mist);
  line-height: 1.6;
}

.lead {
  max-width: 46ch;
  font-size: clamp(18px, 1.6vw, 21px);
  line-height: 1.75;
  color: var(--ink);
}

/* 按钮 */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 14px 26px;
  border-radius: var(--radius-pill);
  border: 1px solid transparent;
  font-size: 16px;
  line-height: 1;
  transition: background-color 0.25s var(--ease-soft),
              color 0.25s var(--ease-soft),
              transform 0.25s var(--ease-soft),
              border-color 0.25s var(--ease-soft);
}

.btn:hover { transform: translateY(-2px); }

.btn--solid {
  background-color: var(--winter);
  color: var(--paper);
}

.btn--solid:hover { background-color: var(--ink); }

.btn--ghost {
  background-color: transparent;
  border-color: rgba(22, 48, 42, 0.28);
  color: var(--ink);
}

.btn--ghost:hover {
  background-color: var(--paper-warm);
  border-color: rgba(22, 48, 42, 0.4);
}

/* 面包屑 */
.breadcrumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  font-size: 14px;
  line-height: 1.6;
  color: var(--mist);
}

.breadcrumbs a {
  color: var(--winter);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
}

.breadcrumbs a:hover { color: var(--ink); }

.crumb-sep { color: rgba(121, 137, 127, 0.7); }

.breadcrumbs [aria-current="page"] { color: var(--ink); }

/* 卡片与旁注 */
.card {
  background-color: var(--paper-warm);
  border-radius: var(--radius-card);
  padding: clamp(22px, 3vw, 34px);
}

.card--note {
  background-color: transparent;
  border: 1px dashed rgba(22, 48, 42, 0.24);
  border-radius: var(--radius-card);
  padding: clamp(20px, 2.6vw, 30px);
}

/* 季节标签 */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 5px 12px;
  border-radius: var(--radius-pill);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  line-height: 1.5;
  background-color: rgba(22, 48, 42, 0.07);
  color: var(--ink);
}

.tag--spring { background-color: var(--spring); color: var(--ink-deep); }
.tag--summer { background-color: var(--summer); color: var(--ink-deep); }
.tag--autumn { background-color: var(--autumn); color: var(--ink-deep); }
.tag--winter { background-color: var(--winter); color: var(--paper); }

/* 图片容器基础规则（页面阶段放置 img） */
.media {
  position: relative;
  display: block;
  overflow: hidden;
  border-radius: var(--radius-card);
  background-color: var(--paper-warm);
  background-image: linear-gradient(
    135deg,
    rgba(232, 167, 181, 0.26),
    rgba(110, 166, 190, 0.22) 48%,
    rgba(223, 160, 87, 0.24) 76%,
    rgba(62, 106, 85, 0.22)
  );
  aspect-ratio: 4 / 3;
}

.media img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.media--tall { aspect-ratio: 3 / 4; }
.media--wide { aspect-ratio: 16 / 9; }
.media--square { aspect-ratio: 1 / 1; }
.media--banner { aspect-ratio: 21 / 9; }

/* 显现动效 */
html.js [data-reveal] {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity 0.32s var(--ease-soft), transform 0.32s var(--ease-soft);
}

html.js [data-reveal].is-visible {
  opacity: 1;
  transform: none;
}

/* 跳转链接 */
.skip-link {
  position: fixed;
  top: 12px;
  left: 12px;
  z-index: 2000;
  padding: 10px 20px;
  border-radius: var(--radius-pill);
  background-color: var(--ink);
  color: var(--paper);
  font-size: 14px;
  line-height: 1.4;
  transform: translateY(-180%);
  transition: transform 0.22s var(--ease-soft);
}

.skip-link:focus-visible {
  transform: translateY(0);
  outline: 2px solid var(--autumn);
  outline-offset: 3px;
}

/* ---------- 5 头部 ---------- */
.site-header {
  position: relative;
  z-index: 900;
}

/* 品牌轨道 */
.brand-rail {
  position: fixed;
  top: 0;
  left: 0;
  z-index: 910;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 26px;
  width: var(--rail-w);
  height: 100vh;
  padding: 30px 0 24px;
  background-color: var(--paper);
  border-right: 1px dashed rgba(22, 48, 42, 0.18);
}

.rail-mark {
  writing-mode: vertical-rl;
  text-orientation: upright;
  padding: 4px 0;
  font-family: var(--font-heading);
  font-size: 25px;
  font-weight: 700;
  letter-spacing: 0.28em;
  color: var(--ink-deep);
  border-radius: 8px;
}

.rail-mark:hover { color: var(--winter); }

.rail-index {
  writing-mode: vertical-rl;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.2em;
  line-height: 1;
  color: var(--mist);
  text-transform: uppercase;
}

.rail-progress {
  position: relative;
  flex: 1 1 auto;
  width: 2px;
  min-height: 60px;
  border-radius: var(--radius-pill);
  background-color: rgba(22, 48, 42, 0.12);
  overflow: hidden;
}

.rail-progress-bar {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: var(--scroll-progress, 0%);
  border-radius: var(--radius-pill);
  background-image: linear-gradient(
    180deg,
    var(--spring),
    var(--summer) 40%,
    var(--autumn) 70%,
    var(--winter)
  );
}

.rail-top {
  display: grid;
  place-items: center;
  width: 38px;
  height: 38px;
  border-radius: var(--radius-pill);
  border: 1px solid rgba(22, 48, 42, 0.25);
  background-color: var(--paper-warm);
  color: var(--ink);
  font-family: var(--font-mono);
  font-size: 15px;
  line-height: 1;
  transition: background-color 0.25s var(--ease-soft),
              color 0.25s var(--ease-soft),
              transform 0.25s var(--ease-soft);
}

.rail-top:hover {
  background-color: var(--winter);
  color: var(--paper);
  transform: translateY(-2px);
}

/* 栏目胶囊组 */
.site-nav {
  position: fixed;
  top: 0;
  right: 0;
  z-index: 950;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  max-width: calc(100% - var(--rail-w));
  padding: 16px 24px;
}

.nav-list {
  display: flex;
  align-items: center;
  gap: 2px;
  padding: 6px;
  border-radius: var(--radius-pill);
  border: 1px solid rgba(22, 48, 42, 0.08);
  background-color: rgba(247, 243, 234, 0.84);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
}

.nav-item { display: flex; }

.nav-pill {
  display: inline-block;
  padding: 9px 16px;
  border-radius: var(--radius-pill);
  font-size: 15px;
  line-height: 1.5;
  color: var(--ink);
  white-space: nowrap;
  transition: background-color 0.25s var(--ease-soft),
              color 0.25s var(--ease-soft),
              transform 0.25s var(--ease-soft);
}

.nav-pill:hover {
  background-color: var(--paper-warm);
  transform: translateY(-2px);
}

.nav-pill[aria-current="page"] {
  background-color: var(--winter);
  color: var(--paper);
}

.nav-pill[aria-current="page"]:hover {
  background-color: var(--ink);
  color: var(--paper);
}

.nav-pill--cta {
  padding: 12px 20px;
  background-color: var(--ink);
  color: var(--paper);
}

.nav-pill--cta:hover {
  background-color: var(--winter);
  color: var(--paper);
}

.nav-meta { display: none; }

.nav-meta-line {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--mist);
}

/* 移动端开关 */
.nav-toggle {
  position: fixed;
  top: 12px;
  right: 16px;
  z-index: 960;
  display: none;
  align-items: center;
  gap: 10px;
  padding: 10px 18px 10px 14px;
  border-radius: var(--radius-pill);
  background-color: var(--ink);
  color: var(--paper);
  font-size: 14px;
  line-height: 1.4;
  letter-spacing: 0.06em;
  box-shadow: 0 6px 18px rgba(13, 21, 18, 0.2);
}

.nav-toggle-bars {
  position: relative;
  display: block;
  width: 18px;
  height: 2px;
  border-radius: 2px;
  background-color: currentColor;
  transition: background-color 0.2s var(--ease-soft);
}

.nav-toggle-bars::before,
.nav-toggle-bars::after {
  content: "";
  position: absolute;
  left: 0;
  width: 18px;
  height: 2px;
  border-radius: 2px;
  background-color: currentColor;
  transition: transform 0.26s var(--ease-soft), top 0.26s var(--ease-soft);
}

.nav-toggle-bars::before { top: -6px; }
.nav-toggle-bars::after { top: 6px; }

.nav-toggle[aria-expanded="true"] .nav-toggle-bars { background-color: transparent; }
.nav-toggle[aria-expanded="true"] .nav-toggle-bars::before { top: 0; transform: rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle-bars::after { top: 0; transform: rotate(-45deg); }

/* ---------- 6 页脚 ---------- */
.site-footer {
  margin-top: clamp(64px, 9vw, 132px);
  padding: clamp(44px, 6vw, 80px) 0 28px;
  border-top-left-radius: 40px;
  border-top-right-radius: 40px;
  background-image: linear-gradient(180deg, #16302A 0%, #0D1512 78%);
  color: var(--paper);
}

.footer-seasons {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 8px;
  height: 8px;
  margin-bottom: clamp(36px, 5vw, 56px);
}

.season-bar {
  display: block;
  height: 100%;
  border-radius: var(--radius-pill);
}

.season-bar--spring { background-color: var(--spring); }
.season-bar--summer { background-color: var(--summer); }
.season-bar--autumn { background-color: var(--autumn); }
.season-bar--winter { background-color: var(--winter); }

.footer-top {
  display: grid;
  grid-template-columns: 1.6fr 1fr 1fr 1.3fr;
  gap: clamp(24px, 4vw, 56px);
}

.footer-brand { min-width: 0; }

.footer-wordmark {
  font-family: var(--font-heading);
  font-size: 34px;
  font-weight: 700;
  letter-spacing: 0.18em;
  line-height: 1.2;
  color: var(--paper);
}

.footer-line {
  margin-top: 14px;
  max-width: 22ch;
  font-size: 15px;
  line-height: 1.8;
  color: rgba(247, 243, 234, 0.72);
}

.footer-col { min-width: 0; }

.footer-title {
  margin-bottom: 16px;
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.18em;
  line-height: 1.6;
  text-transform: uppercase;
  color: rgba(247, 243, 234, 0.52);
}

.footer-list { display: block; }

.footer-list li + li { margin-top: 10px; }

.footer-list a {
  font-size: 15px;
  line-height: 1.7;
  color: rgba(247, 243, 234, 0.86);
  text-decoration: underline;
  text-decoration-color: transparent;
  text-underline-offset: 4px;
  transition: color 0.22s var(--ease-soft), text-decoration-color 0.22s var(--ease-soft);
}

.footer-list a:hover {
  color: var(--paper);
  text-decoration-color: var(--autumn);
}

.footer-text {
  font-size: 15px;
  line-height: 1.7;
  color: rgba(247, 243, 234, 0.82);
  overflow-wrap: anywhere;
}

.footer-text + .footer-text { margin-top: 10px; }

.footer-base {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px 32px;
  margin-top: clamp(36px, 5vw, 56px);
  padding-top: 22px;
  border-top: 1px dashed rgba(247, 243, 234, 0.22);
  font-size: 13px;
  line-height: 1.7;
  color: rgba(247, 243, 234, 0.62);
}

.footer-note { max-width: 52ch; }

.footer-legal {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
}

.footer-copy {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
}

/* ---------- 7 响应式 ---------- */
@media (max-width: 1199px) and (min-width: 1024px) {
  .nav-pill { padding: 8px 12px; font-size: 14px; }
  .nav-pill--cta { padding: 10px 16px; }
  .site-nav { padding: 14px 18px; gap: 8px; }
}

@media (min-width: 1024px) {
  body { padding-left: var(--rail-w); }
}

@media (max-width: 1023px) {
  body { font-size: 16.5px; line-height: 1.8; }

  .brand-rail {
    flex-direction: row;
    align-items: center;
    gap: 14px;
    width: 100%;
    height: 56px;
    padding: 0 108px 0 20px;
    border-right: 0;
    border-bottom: 1px dashed rgba(22, 48, 42, 0.18);
  }

  .rail-mark {
    writing-mode: horizontal-tb;
    text-orientation: mixed;
    font-size: 20px;
    letter-spacing: 0.22em;
    padding: 0;
  }

  .rail-index {
    writing-mode: horizontal-tb;
    font-size: 11px;
    letter-spacing: 0.16em;
  }

  .rail-progress {
    position: absolute;
    left: 0;
    bottom: -1px;
    width: 100%;
    height: 2px;
    min-height: 0;
    flex: 0 0 auto;
    border-radius: 0;
    background-color: rgba(22, 48, 42, 0.1);
  }

  .rail-progress-bar {
    top: 0;
    left: 0;
    width: var(--scroll-progress, 0%);
    height: 100%;
    border-radius: 0;
    background-image: linear-gradient(
      90deg,
      var(--spring),
      var(--summer) 38%,
      var(--autumn) 68%,
      var(--winter)
    );
  }

  .rail-top { display: none; }

  .nav-toggle { display: inline-flex; }

  .site-nav {
    top: auto;
    right: 0;
    bottom: 0;
    left: 0;
    flex-direction: column;
    flex-wrap: nowrap;
    align-items: stretch;
    gap: 14px;
    max-width: none;
    padding: 22px 20px calc(22px + env(safe-area-inset-bottom, 0px));
    border-top-left-radius: 28px;
    border-top-right-radius: 28px;
    background-color: var(--paper);
    box-shadow: 0 -18px 42px rgba(13, 21, 18, 0.18);
    transform: translateY(112%);
    visibility: hidden;
    transition: transform 0.32s var(--ease-soft), visibility 0.32s var(--ease-soft);
  }

  .site-nav[data-open] {
    transform: translateY(0);
    visibility: visible;
  }

  .nav-list {
    flex-direction: column;
    align-items: stretch;
    gap: 4px;
    padding: 0;
    border: 0;
    border-radius: 0;
    background-color: transparent;
    backdrop-filter: none;
    -webkit-backdrop-filter: none;
  }

  .nav-item { display: block; }

  .nav-pill {
    display: block;
    padding: 14px 16px;
    border-radius: 18px;
    font-size: 16px;
  }

  .nav-pill--cta {
    display: block;
    text-align: center;
    padding: 15px 20px;
    border-radius: 18px;
    font-size: 16px;
  }

  .nav-meta {
    display: block;
    padding-top: 14px;
    border-top: 1px dashed rgba(22, 48, 42, 0.2);
  }

  .nav-meta-line + .nav-meta-line { margin-top: 6px; }

  body.nav-open { overflow: hidden; }

  .site-main { padding-top: 80px; }

  .footer-top { grid-template-columns: 1fr 1fr; }
  .footer-brand { grid-column: 1 / -1; }
  .footer-base { flex-direction: column; align-items: flex-start; }
}

@media (max-width: 599px) {
  .site-footer {
    border-top-left-radius: 28px;
    border-top-right-radius: 28px;
  }

  .footer-top { grid-template-columns: 1fr; gap: 30px; }
  .footer-wordmark { font-size: 28px; }
  .footer-line { max-width: none; }
  .footer-seasons { gap: 6px; height: 7px; }
}

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

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

  html.js [data-reveal] {
    opacity: 1;
    transform: none;
    transition: none;
  }
}