/* ============================================================
   废纸桶 · 应用介绍页
   天空蓝主调 —— 雾白纸 / 冷调卡片 / 霞鹜文楷
   ============================================================ */

/* ---------- 主题变量 ---------- */
:root {
  --bg-page: #f1f2f4;
  --bg-card: #f8f9fb;
  --bg-sunken: #e9ecf0;
  --bg-mist: #e6eef5;
  --ink: #2b3038;
  --ink-muted: #5e656f;
  --ink-faint: #9aa1ab;
  --sky: #4a7fa8;
  --sky-deep: #345d80;
  --sky-soft: #8ab4d4;
  --mist: #6b8589;
  --slate: #6b7280;
  --dusk: #8a7a9b;
  --clay: #a87561;
  --line: #d9dce2;
  --line-strong: #b8bcc4;
  --shadow-paper: 0 1px 2px rgba(45, 60, 80, 0.04), 0 6px 24px -10px rgba(45, 60, 80, 0.08);
  --shadow-lift: 0 2px 4px rgba(45, 60, 80, 0.06), 0 16px 40px -12px rgba(45, 60, 80, 0.14);
  --radius-sm: 6px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --ease-out: cubic-bezier(0.22, 0.61, 0.36, 1);
  --ease-soft: cubic-bezier(0.4, 0, 0.2, 1);
}

[data-theme="dark"] {
  --bg-page: #1a1d22;
  --bg-card: #232830;
  --bg-sunken: #2a2f37;
  --bg-mist: #1f2832;
  --ink: #e8eaef;
  --ink-muted: #a0a5af;
  --ink-faint: #767b85;
  --sky: #8ab4d4;
  --sky-deep: #a8c8e0;
  --sky-soft: #6b95b8;
  --mist: #9ab4b8;
  --slate: #9ca3af;
  --dusk: #b09bc0;
  --clay: #d4a08a;
  --line: #363a42;
  --line-strong: #464b54;
  --shadow-paper: 0 1px 2px rgba(0, 0, 0, 0.3), 0 6px 24px -10px rgba(0, 0, 0, 0.5);
  --shadow-lift: 0 2px 4px rgba(0, 0, 0, 0.4), 0 16px 40px -12px rgba(0, 0, 0, 0.6);
}

/* ---------- 重置 ---------- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  font-family: "LXGW WenKai Screen", "霞鹜文楷", "Songti SC", "STSong", "SimSun", serif;
  background: var(--bg-page);
  color: var(--ink);
  font-size: 16px;
  line-height: 1.85;
  letter-spacing: 0.02em;
  word-break: break-word;
  overflow-x: hidden;
  min-height: 100vh;
  transition: background 0.4s var(--ease-out), color 0.4s var(--ease-out);
}
img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
button { font: inherit; color: inherit; background: none; border: none; cursor: pointer; }
em { font-style: normal; color: var(--sky-deep); font-weight: 500; }
[data-theme="dark"] em { color: var(--sky); }

/* ---------- 纸纤维纹理 ---------- */
.paper-grain {
  position: fixed; inset: 0; z-index: 0; pointer-events: none;
  opacity: 0.45;
  background-image:
    radial-gradient(circle at 20% 30%, rgba(93, 130, 99, 0.04) 0, transparent 1px),
    radial-gradient(circle at 80% 60%, rgba(107, 133, 137, 0.04) 0, transparent 1px),
    radial-gradient(circle at 50% 80%, rgba(125, 106, 82, 0.03) 0, transparent 1px);
  background-size: 7px 7px, 11px 11px, 13px 13px;
  mix-blend-mode: multiply;
}
[data-theme="dark"] .paper-grain { opacity: 0.3; mix-blend-mode: screen; }

/* 背景柔光层 */
body::before {
  content: "";
  position: fixed; inset: 0; z-index: 0; pointer-events: none;
  background:
    radial-gradient(ellipse 80% 50% at 20% 0%, rgba(93, 130, 99, 0.06), transparent 70%),
    radial-gradient(ellipse 60% 40% at 80% 100%, rgba(107, 133, 137, 0.05), transparent 70%);
  opacity: 1;
  transition: opacity 0.4s var(--ease-out);
}
[data-theme="dark"] body::before {
  background:
    radial-gradient(ellipse 80% 50% at 20% 0%, rgba(142, 179, 148, 0.05), transparent 70%),
    radial-gradient(ellipse 60% 40% at 80% 100%, rgba(154, 180, 184, 0.04), transparent 70%);
}

/* ---------- 通用容器 ---------- */
body > * { position: relative; z-index: 1; }
.masthead, .essay-block, .platforms, .features, .gallery, .privacy-pledge, .about-block, .foot {
  max-width: 1100px;
  margin: 0 auto;
  padding-left: 28px;
  padding-right: 28px;
}
/* 锚点跳转时预留吸顶导航高度，避免标题被导航遮挡 */
#download, #features, #shots, #privacy, #about {
  scroll-margin-top: 84px;
}

/* ---------- 顶部导航（液态玻璃吸顶） ---------- */
.topnav {
  position: sticky;
  top: 0;
  z-index: 90;
  background: color-mix(in srgb, var(--bg-page) 55%, transparent);
  backdrop-filter: blur(18px) saturate(180%);
  -webkit-backdrop-filter: blur(18px) saturate(180%);
  border-bottom: 1px solid color-mix(in srgb, var(--line) 50%, transparent);
  box-shadow: 0 6px 24px -16px rgba(45, 60, 80, 0.18);
}
.topnav-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 12px 28px;
  display: flex;
  align-items: center;
  gap: 16px;
}
.topnav-brand {
  display: inline-flex; align-items: center; gap: 8px;
  color: var(--ink);
  font-size: 16px;
  letter-spacing: 0.08em;
}
.topnav-brand svg { color: var(--sky); }
.topnav-links {
  display: flex; align-items: center; gap: 4px;
  margin-left: auto;
}
.topnav-links a {
  position: relative;
  font-size: 14px;
  color: var(--ink-muted);
  padding: 6px 14px;
  border-radius: 999px;
  transition: color 0.2s var(--ease-out), background 0.2s var(--ease-out);
}
.topnav-links a:hover { color: var(--sky-deep); background: var(--bg-mist); }
[data-theme="dark"] .topnav-links a:hover { color: var(--sky); }
.topnav-links a.is-active { color: var(--sky-deep); background: var(--bg-mist); }
[data-theme="dark"] .topnav-links a.is-active { color: var(--sky); }
.topnav-mode {
  font-size: 13px; color: var(--ink-muted);
  padding: 6px 14px; border-radius: 999px;
  border: 1px solid var(--line-strong);
  transition: all 0.2s var(--ease-out);
  flex-shrink: 0;
}
.topnav-mode:hover { color: var(--sky-deep); border-color: var(--sky); transform: scale(1.02); }

/* ---------- 报头（双栏：文字 + 桶吉祥物） ---------- */
.masthead {
  text-align: left;
  padding-top: 64px;
  padding-bottom: 88px;
  position: relative;
}
.masthead-grid {
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  gap: 40px;
  align-items: center;
}
.masthead-text { text-align: center; }
.masthead-eyebrow {
  font-size: 13px; letter-spacing: 0.4em; color: var(--sky);
  margin-bottom: 22px;
}
.masthead-title {
  font-size: clamp(38px, 6.4vw, 66px);
  font-weight: 400;
  letter-spacing: 0.08em;
  color: var(--ink);
  line-height: 1.2;
  margin-bottom: 16px;
  position: relative;
}
.masthead-title::after {
  content: "";
  display: block;
  width: 88px; height: 6px;
  margin: 16px auto 0;
  background:
    radial-gradient(ellipse at center, var(--sky-soft) 0%, transparent 70%);
  opacity: 0.6;
}
.masthead-sub {
  font-size: clamp(15px, 2vw, 19px);
  color: var(--ink-muted);
  letter-spacing: 0.12em;
  margin-bottom: 30px;
}
.masthead-rule {
  display: flex; align-items: center; justify-content: center;
  gap: 12px;
  margin-bottom: 20px;
}
.rule-line {
  width: 60px; height: 1px;
  background: linear-gradient(to right, transparent, var(--sky), transparent);
  opacity: 0.6;
}
.rule-dot {
  width: 5px; height: 5px; border-radius: 50%;
  background: var(--sky); opacity: 0.7;
}
.rule-seal {
  font-size: 12px; color: var(--sky-deep);
  letter-spacing: 0.3em;
  padding: 3px 10px;
  border: 1px solid var(--sky);
  border-radius: 4px;
  opacity: 0.85;
  background: var(--bg-card);
}
[data-theme="dark"] .rule-seal { color: var(--sky-soft); border-color: var(--sky-soft); }
.masthead-meta {
  display: flex; align-items: center; justify-content: center;
  gap: 14px;
  font-size: 13px; color: var(--ink-faint);
  letter-spacing: 0.2em;
}
.dot-sep { color: var(--ink-faint); opacity: 0.6; }

/* 报头 CTA */
.hero-actions {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: 12px;
  margin-top: 30px;
}
.hero-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 7px;
  font-size: 15px;
  letter-spacing: 0.12em;
  padding: 12px 24px;
  border-radius: 999px;
  border: 1px solid var(--line-strong);
  color: var(--ink);
  background: var(--bg-card);
  box-shadow: var(--shadow-paper);
  transition: all 0.25s var(--ease-out);
  cursor: pointer;
}
.hero-btn:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lift);
  border-color: var(--sky);
  color: var(--sky-deep);
}
[data-theme="dark"] .hero-btn:hover { color: var(--sky); }
.hero-btn.is-primary {
  background: linear-gradient(135deg, var(--sky-deep), var(--sky));
  color: #fff;
  border-color: transparent;
  box-shadow: 0 8px 22px -8px rgba(74, 127, 168, 0.5);
}
.hero-btn.is-primary:hover {
  color: #fff;
  box-shadow: 0 12px 30px -8px rgba(74, 127, 168, 0.6);
  border-color: transparent;
}
.hero-btn.is-ghost { background: transparent; }

/* 状态徽章 */
.hero-note {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: 8px;
  margin-top: 20px;
}
.hero-chip {
  font-size: 12px;
  color: var(--ink-muted);
  letter-spacing: 0.08em;
  padding: 4px 12px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--bg-card);
}
.hero-chip b { color: var(--sky-deep); font-weight: 500; }
[data-theme="dark"] .hero-chip b { color: var(--sky-soft); }
.hero-chip.is-soft { color: var(--ink-faint); border-style: dashed; }

/* 桶吉祥物场景 */
.masthead-visual {
  display: flex;
  align-items: center;
  justify-content: center;
}
.bucket-scene {
  position: relative;
  width: 260px;
  height: 260px;
  display: flex;
  align-items: center;
  justify-content: center;
}
.bucket-shape { display: block; }
.bucket-paper { transform-origin: center center; }
.bucket-paper.p1 { animation: paper-float 5.2s var(--ease-soft) infinite; }
.bucket-paper.p2 { animation: paper-float 6.4s var(--ease-soft) 0.6s infinite; }
.bucket-paper.p3 { animation: paper-float 4.6s var(--ease-soft) 1.2s infinite; }
@keyframes paper-float {
  0%, 100% { transform: translateY(0) rotate(0deg); }
  50% { transform: translateY(-7px) rotate(2.5deg); }
}
.bucket-scene::after {
  content: "";
  position: absolute;
  inset: -30px;
  background: radial-gradient(ellipse at center, var(--bg-mist) 0%, transparent 72%);
  border-radius: 50%;
  z-index: -1;
  opacity: 0.8;
}

/* ---------- 通用段落标题 ---------- */
.section-head {
  text-align: center;
  margin-bottom: 56px;
  position: relative;
}
.section-seal {
  display: inline-flex; align-items: center; justify-content: center;
  width: 40px; height: 40px;
  font-size: 16px; color: var(--sky-deep);
  border: 1.5px solid var(--sky);
  border-radius: 50%;
  margin-bottom: 18px;
  font-weight: 500;
  letter-spacing: 0;
  opacity: 0.9;
  background: var(--bg-card);
}
[data-theme="dark"] .section-seal { color: var(--sky-soft); border-color: var(--sky-soft); }
.section-title {
  font-size: clamp(24px, 3.6vw, 34px);
  font-weight: 400;
  letter-spacing: 0.12em;
  color: var(--ink);
  margin-bottom: 12px;
}
.section-desc {
  font-size: 15px; color: var(--ink-muted);
  letter-spacing: 0.08em;
}

/* ---------- 介绍段（手写信纸） ---------- */
.essay-block {
  padding-top: 16px;
  padding-bottom: 96px;
}
.essay-paper {
  position: relative;
  background: color-mix(in srgb, var(--bg-card) 80%, transparent);
  border: 1px solid var(--line);
  border-top: 1px dashed var(--line-strong);
  border-radius: var(--radius-md);
  padding: 60px 56px 48px;
  box-shadow: var(--shadow-paper), inset 0 1px 0 color-mix(in srgb, #fff 45%, transparent);
  max-width: 860px;
  margin: 0 auto;
  backdrop-filter: blur(10px) saturate(150%);
  -webkit-backdrop-filter: blur(10px) saturate(150%);
}
.essay-tape {
  position: absolute;
  top: -12px; left: 50%;
  transform: translateX(-50%) rotate(-1.2deg);
  width: 96px; height: 24px;
  background: rgba(95, 125, 131, 0.16);
  border: 1px dashed rgba(95, 125, 131, 0.30);
  border-radius: 2px;
}
.essay-paper p {
  font-size: 16px;
  line-height: 2.05;
  color: var(--ink);
  margin-bottom: 16px;
  text-indent: 2em;
}
.essay-paper p:first-child {
  font-size: 18px;
  color: var(--sky-deep);
  text-indent: 0;
  margin-bottom: 24px;
  letter-spacing: 0.1em;
}
[data-theme="dark"] .essay-paper p:first-child { color: var(--sky); }
.essay-sign {
  text-align: right;
  text-indent: 0 !important;
  color: var(--ink-muted) !important;
  font-size: 14px !important;
  margin-top: 28px !important;
  letter-spacing: 0.15em;
}

/* ---------- 四端 ---------- */
.platforms { padding-top: 40px; padding-bottom: 100px; }
.platform-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 18px;
}
.platform-card {
  position: relative;
  background: color-mix(in srgb, var(--bg-card) 72%, transparent);
  border: 1px solid color-mix(in srgb, var(--line) 80%, transparent);
  border-radius: var(--radius-lg);
  padding: 28px 24px 24px;
  text-align: left;
  box-shadow: var(--shadow-paper), inset 0 1px 0 color-mix(in srgb, #fff 40%, transparent);
  transition: border-color 0.25s var(--ease-out), transform 0.25s var(--ease-out), box-shadow 0.25s var(--ease-out), background 0.25s var(--ease-out);
  display: flex;
  flex-direction: column;
  backdrop-filter: blur(10px) saturate(140%);
  -webkit-backdrop-filter: blur(10px) saturate(140%);
}
.platform-card:hover {
  border-color: var(--accent);
  transform: translateY(-3px);
  box-shadow: var(--shadow-lift), inset 0 1px 0 color-mix(in srgb, #fff 50%, transparent);
}
.platform-icon {
  width: 52px; height: 52px;
  display: flex; align-items: center; justify-content: center;
  color: var(--accent);
  background: color-mix(in srgb, var(--accent) 10%, var(--bg-card));
  border-radius: 14px;
  margin-bottom: 16px;
}
.platform-seal {
  position: absolute;
  top: 18px; right: 18px;
  font-size: 11px;
  color: var(--ink-faint);
  letter-spacing: 0.1em;
  opacity: 0.7;
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 2px 9px;
}
.platform-name {
  font-size: 21px;
  font-weight: 400;
  color: var(--ink);
  letter-spacing: 0.08em;
  margin-bottom: 8px;
}
.platform-state {
  font-size: 13px;
  color: var(--ink-muted);
  line-height: 1.7;
  margin-bottom: 18px;
  flex: 1;
}
.platform-cta {
  display: inline-block;
  font-size: 13px;
  letter-spacing: 0.12em;
  padding: 8px 16px;
  color: var(--accent);
  border: 1px solid color-mix(in srgb, var(--accent) 55%, transparent);
  border-radius: 999px;
  text-align: center;
  transition: all 0.2s var(--ease-out);
}
.platform-cta:hover {
  background: color-mix(in srgb, var(--accent) 12%, transparent);
  border-color: var(--accent);
}
.platform-cta.is-wait {
  color: var(--ink-faint);
  border-color: var(--line-strong);
  cursor: not-allowed;
  border-style: dashed;
  background: transparent;
}
.platform-cta.is-wait:hover { background: transparent; }
.platform-card.is-hot {
  background: linear-gradient(180deg, var(--bg-card) 0%, var(--bg-mist) 100%);
  border-color: var(--mist);
}
.platform-card.is-web {
  background: linear-gradient(180deg, var(--bg-card) 0%, var(--bg-mist) 100%);
  border-color: var(--sky-soft);
}

/* ---------- 下载说明 ---------- */
.download-note { padding-top: 24px; }
.download-note-inner {
  position: relative;
  background: var(--bg-sunken);
  border: 1px dashed var(--line-strong);
  border-radius: var(--radius-md);
  padding: 26px 40px 22px 56px;
  max-width: 760px;
  margin: 0 auto;
}
.download-note-mark {
  position: absolute;
  left: 18px; top: 50%;
  transform: translateY(-50%) rotate(-4deg);
  width: 30px; height: 30px;
  display: flex; align-items: center; justify-content: center;
  background: var(--clay);
  color: #fff;
  font-size: 13px;
  border-radius: 6px;
  letter-spacing: 0;
}
[data-theme="dark"] .download-note-mark { color: var(--bg-page); }
.download-note-inner p {
  font-size: 14px;
  color: var(--ink-muted);
  line-height: 1.9;
  margin-bottom: 6px;
}
.download-note-sub {
  font-size: 13px !important;
  color: var(--ink-faint) !important;
}

/* ---------- 功能 ---------- */
.features { padding-top: 40px; padding-bottom: 100px; }
.feature-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
}
.feature-card {
  position: relative;
  background: color-mix(in srgb, var(--bg-card) 70%, transparent);
  border: 1px solid color-mix(in srgb, var(--line) 80%, transparent);
  border-radius: var(--radius-md);
  padding: 28px 24px 26px;
  box-shadow: var(--shadow-paper), inset 0 1px 0 color-mix(in srgb, #fff 40%, transparent);
  transition: border-color 0.25s var(--ease-out), transform 0.25s var(--ease-out), box-shadow 0.25s var(--ease-out);
  --accent: var(--ink-muted);
  backdrop-filter: blur(8px) saturate(140%);
  -webkit-backdrop-filter: blur(8px) saturate(140%);
}
.feature-card:nth-child(4n+1) { --accent: var(--sky); }
.feature-card:nth-child(4n+2) { --accent: var(--mist); }
.feature-card:nth-child(4n+3) { --accent: var(--dusk); }
.feature-card:nth-child(4n+4) { --accent: var(--slate); }
.feature-card:hover {
  border-color: var(--accent);
  transform: translateY(-3px);
  box-shadow: var(--shadow-lift);
}
.feature-num {
  position: absolute;
  top: 16px; right: 18px;
  font-size: 12px;
  color: var(--accent);
  opacity: 0.55;
  letter-spacing: 0.1em;
  transition: opacity 0.25s var(--ease-out);
}
.feature-card:hover .feature-num { opacity: 0.9; }
.feature-card::before {
  content: "";
  display: block;
  width: 26px; height: 3px;
  border-radius: 2px;
  background: var(--accent);
  opacity: 0.7;
  margin-bottom: 14px;
}
.feature-card h3 {
  font-size: 18px;
  font-weight: 400;
  color: var(--ink);
  letter-spacing: 0.06em;
  margin-bottom: 10px;
}
.feature-card p {
  font-size: 14px;
  color: var(--ink-muted);
  line-height: 1.85;
  letter-spacing: 0.02em;
}

/* ---------- 界面画廊 ---------- */
.gallery { padding-top: 40px; padding-bottom: 100px; }
.gallery-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 28px 18px;
}
.shot {
  cursor: pointer;
  transition: transform 0.25s var(--ease-out);
}
.shot:hover { transform: translateY(-3px); }
.phone {
  position: relative;
  background: transparent;
  border: none;
  border-radius: 0;
  padding: 0;
  box-shadow: none;
  overflow: visible;
}
.phone-notch { display: none; }
.phone img {
  width: 100%;
  height: auto;
  object-fit: contain;
  border-radius: 10px;
  background: transparent;
  display: block;
  border: 1px solid var(--line);
  transition: border-color 0.25s var(--ease-out), box-shadow 0.25s var(--ease-out);
  min-height: 120px;
}
.phone img:not([src]) {
  background:
    linear-gradient(var(--bg-mist), var(--bg-mist)) padding-box,
    var(--bg-sunken);
  border-style: dashed;
}
.shot:hover .phone img {
  border-color: var(--line-strong);
  box-shadow: var(--shadow-lift);
}
[data-theme="dark"] .shot:hover .phone img { border-color: var(--ink-faint); }
.shot figcaption {
  margin-top: 10px;
  font-size: 12px;
  color: var(--ink-faint);
  text-align: center;
  letter-spacing: 0.04em;
  line-height: 1.5;
}

/* ---------- 灯箱 ---------- */
.lightbox {
  position: fixed; inset: 0; z-index: 100;
  background: rgba(20, 18, 14, 0.82);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  display: none;
  align-items: center; justify-content: center;
  padding: 40px 20px;
}
.lightbox.is-open { display: flex; }
.lightbox-stage {
  display: flex; flex-direction: column;
  align-items: center; gap: 18px;
  max-width: 100%; max-height: 100%;
}
.lightbox-phone {
  position: relative;
  background: transparent;
  border: none;
  border-radius: 0;
  padding: 0;
  box-shadow: 0 30px 80px rgba(0, 0, 0, 0.5);
  width: min(360px, 80vw);
  max-height: 80vh;
  overflow: visible;
}
.lightbox-phone .phone-notch { display: none; }
.lightbox-phone img {
  width: 100%;
  height: auto;
  max-height: 80vh;
  object-fit: contain;
  border-radius: 4px;
  display: block;
  background: transparent;
}
.lightbox-stage figcaption {
  color: rgba(255, 255, 255, 0.85);
  font-size: 14px;
  letter-spacing: 0.15em;
}
.lightbox-close, .lightbox-prev, .lightbox-next {
  position: absolute;
  color: rgba(255, 255, 255, 0.9);
  font-size: 18px;
  border: 1px solid rgba(255, 255, 255, 0.3);
  border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  transition: all 0.2s var(--ease-out);
}
.lightbox-close:hover, .lightbox-prev:hover, .lightbox-next:hover {
  background: rgba(255, 255, 255, 0.15);
  border-color: rgba(255, 255, 255, 0.6);
}
.lightbox-close {
  top: 24px; right: 24px;
  font-size: 13px; letter-spacing: 0.1em;
  border-radius: 22px;
  padding: 0 12px;
  height: 44px;
}
.lightbox-prev, .lightbox-next {
  top: 50%; transform: translateY(-50%);
  width: 48px; height: 48px;
  font-size: 28px;
}
.lightbox-prev { left: 24px; }
.lightbox-next { right: 24px; }

/* ---------- 小程序二维码弹层 ---------- */
.qr-modal {
  position: fixed; inset: 0; z-index: 110;
  background: rgba(20, 18, 14, 0.82);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  display: none;
  align-items: center; justify-content: center;
  padding: 40px 20px;
}
.qr-modal.is-open { display: flex; }
.qr-modal-box {
  position: relative;
  background: color-mix(in srgb, var(--bg-card) 78%, transparent);
  border: 1px solid color-mix(in srgb, var(--line) 80%, transparent);
  border-radius: var(--radius-lg);
  padding: 40px 44px 32px;
  text-align: center;
  max-width: 380px;
  width: 100%;
  box-shadow: var(--shadow-lift), inset 0 1px 0 color-mix(in srgb, #fff 45%, transparent);
  backdrop-filter: blur(18px) saturate(180%);
  -webkit-backdrop-filter: blur(18px) saturate(180%);
  animation: qr-pop 0.28s var(--ease-out);
}
@keyframes qr-pop {
  from { opacity: 0; transform: scale(0.92) translateY(8px); }
  to { opacity: 1; transform: scale(1) translateY(0); }
}
.qr-modal-close {
  position: absolute;
  top: 16px; right: 16px;
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--ink-faint);
  border: 1px solid var(--line-strong);
  border-radius: 999px;
  padding: 4px 12px;
  transition: all 0.2s var(--ease-out);
}
.qr-modal-close:hover { color: var(--sky-deep); border-color: var(--sky); }
[data-theme="dark"] .qr-modal-close:hover { color: var(--sky); }
.qr-modal-title { font-size: 22px; letter-spacing: 0.2em; color: var(--ink); margin-bottom: 6px; }
.qr-modal-sub { font-size: 13px; color: var(--ink-muted); letter-spacing: 0.12em; margin-bottom: 24px; }
.qr-modal-img {
  display: inline-block;
  padding: 12px;
  background: #fff;
  border-radius: 12px;
  box-shadow: var(--shadow-paper);
}
.qr-modal-img img { width: 220px; height: 220px; display: block; }
.qr-modal-hint {
  margin-top: 18px;
  font-size: 13px;
  color: var(--ink-faint);
  line-height: 1.8;
  letter-spacing: 0.04em;
}

/* ---------- 隐私承诺 ---------- */
.privacy-pledge { padding-top: 40px; padding-bottom: 100px; }
.pledge-paper {
  position: relative;
  background: color-mix(in srgb, var(--bg-card) 80%, transparent);
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  padding: 52px 48px 44px;
  box-shadow: var(--shadow-paper), inset 0 1px 0 color-mix(in srgb, #fff 45%, transparent);
  max-width: 860px;
  margin: 0 auto;
  backdrop-filter: blur(10px) saturate(150%);
  -webkit-backdrop-filter: blur(10px) saturate(150%);
}
.pledge-paper::before {
  content: "";
  position: absolute;
  top: 14px; left: 14px; right: 14px; bottom: 14px;
  border: 1px solid var(--line);
  border-radius: 8px;
  pointer-events: none;
}
.pledge-seal {
  position: absolute;
  top: -20px; right: 36px;
  width: 56px; height: 56px;
  display: flex; align-items: center; justify-content: center;
  background: var(--clay);
  color: #fff;
  border-radius: 8px;
  font-size: 22px;
  letter-spacing: 0;
  transform: rotate(-6deg);
  box-shadow: 0 4px 12px rgba(184, 130, 107, 0.35);
}
[data-theme="dark"] .pledge-seal { color: #1a1c19; }
.pledge-title {
  font-size: 24px;
  font-weight: 400;
  letter-spacing: 0.15em;
  color: var(--ink);
  margin-bottom: 26px;
  text-align: center;
}
.pledge-list { list-style: none; }
.pledge-list li {
  position: relative;
  font-size: 15px;
  line-height: 2;
  color: var(--ink);
  padding-left: 26px;
  margin-bottom: 14px;
  letter-spacing: 0.02em;
}
.pledge-list li::before {
  content: "·";
  position: absolute;
  left: 8px; top: -2px;
  color: var(--sky);
  font-size: 22px;
  font-weight: 700;
}

/* ---------- 关于 ---------- */
.about-block { padding-top: 40px; padding-bottom: 80px; }
.about-card {
  background: var(--bg-card);
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  padding: 12px 32px;
  box-shadow: var(--shadow-paper);
  max-width: 560px;
  margin: 0 auto;
}
.about-row {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  padding: 16px 0;
  border-bottom: 1px dashed var(--line);
  font-size: 15px;
}
.about-row:last-child { border-bottom: none; }
.about-row span:first-child {
  color: var(--ink-muted);
  letter-spacing: 0.15em;
  font-size: 13px;
}
.about-row span:last-child {
  color: var(--ink);
  letter-spacing: 0.04em;
}

/* ---------- 轻提示 toast（液态玻璃 + 类型区分） ---------- */
.toast-box {
  position: fixed;
  left: 50%;
  bottom: 40px;
  transform: translateX(-50%) translateY(18px) scale(0.96);
  z-index: 200;
  max-width: min(86vw, 440px);
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 12px 18px 12px 14px;
  background: color-mix(in srgb, var(--bg-card) 72%, transparent);
  color: var(--ink);
  font-size: 14px;
  letter-spacing: 0.04em;
  line-height: 1.6;
  border-radius: 14px;
  border: 1px solid color-mix(in srgb, var(--line) 80%, transparent);
  box-shadow: var(--shadow-lift), inset 0 1px 0 color-mix(in srgb, #fff 45%, transparent);
  backdrop-filter: blur(16px) saturate(160%);
  -webkit-backdrop-filter: blur(16px) saturate(160%);
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.28s var(--ease-out), transform 0.28s var(--ease-out);
}
.toast-box.is-show {
  opacity: 1;
  transform: translateX(-50%) translateY(0) scale(1);
}
/* toast 图标 */
.toast-icon {
  flex-shrink: 0;
  width: 26px;
  height: 26px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg-mist);
  color: var(--sky-deep);
  font-size: 13px;
  font-weight: 700;
}
.toast-icon.is-ok { color: #2f7d4f; background: color-mix(in srgb, #2f7d4f 14%, var(--bg-card)); }
.toast-icon.is-err { color: #c0523f; background: color-mix(in srgb, #c0523f 14%, var(--bg-card)); }
[data-theme="dark"] .toast-icon.is-ok { color: #6fce92; }
[data-theme="dark"] .toast-icon.is-err { color: #e08a78; }
/* toast 文案 */
.toast-text { flex: 1; }

/* ---------- 底部 ---------- */
.foot {
  padding-top: 40px;
  padding-bottom: 56px;
  text-align: center;
}
.foot-rule {
  width: 80px; height: 1px;
  background: var(--line-strong);
  margin: 0 auto 28px;
}
.foot-legal {
  display: flex; flex-wrap: wrap;
  align-items: center; justify-content: center;
  gap: 8px 12px;
  font-size: 13px;
  color: var(--ink-muted);
  margin-bottom: 16px;
}
.foot-legal a {
  padding: 4px 4px;
  position: relative;
  transition: color 0.2s var(--ease-out);
}
.foot-legal a::after {
  content: "";
  position: absolute;
  left: 4px; right: 4px; bottom: 2px;
  height: 1px;
  background: currentColor;
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.25s var(--ease-out);
}
.foot-legal a:hover { color: var(--sky-deep); }
[data-theme="dark"] .foot-legal a:hover { color: var(--sky); }
.foot-legal a:hover::after { transform: scaleX(1); }
.foot-copy {
  font-size: 13px;
  color: var(--ink-faint);
  letter-spacing: 0.12em;
  display: flex; flex-wrap: wrap;
  align-items: center; justify-content: center;
  gap: 8px;
}

/* ---------- Reveal 动画（渐进增强） ---------- */
html.js-ready .reveal,
html.js-ready .reveal-stagger {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity 0.7s var(--ease-out), transform 0.7s var(--ease-out);
}
html.js-ready .reveal.is-visible,
html.js-ready .reveal-stagger.is-visible {
  opacity: 1;
  transform: translateY(0);
}
html.js-ready .reveal-stagger.is-visible {
  transition-delay: calc(var(--i, 0) * 90ms);
}

/* ---------- 响应式 ---------- */
@media (max-width: 900px) {
  .masthead-grid { grid-template-columns: 1fr; gap: 28px; }
  .masthead-visual { order: -1; }
  .bucket-scene { width: 200px; height: 200px; }
  .platform-grid { grid-template-columns: repeat(2, 1fr); }
  .feature-grid { grid-template-columns: repeat(2, 1fr); }
  .gallery-grid { grid-template-columns: repeat(3, 1fr); }
  .topnav-inner, .masthead, .essay-block, .platforms, .features, .gallery, .privacy-pledge, .about-block, .foot {
    padding-left: 20px;
    padding-right: 20px;
  }
  .essay-paper { padding: 44px 28px 36px; }
  .pledge-paper { padding: 40px 28px 32px; }
}

@media (max-width: 560px) {
  .topnav-inner { padding: 12px 16px; }
  .topnav-links { gap: 0; }
  .topnav-links a { padding: 6px 10px; font-size: 13px; }
  .topnav-brand span { display: none; }
  .masthead { padding-top: 40px; padding-bottom: 60px; }
  .masthead-eyebrow { font-size: 11px; letter-spacing: 0.3em; }
  .platform-grid { grid-template-columns: 1fr; gap: 14px; }
  .feature-grid { grid-template-columns: 1fr; gap: 14px; }
  .gallery-grid { grid-template-columns: repeat(2, 1fr); gap: 22px 14px; }
  .essay-paper p { font-size: 15px; line-height: 1.95; }
  .pledge-list li { font-size: 14px; }
  .lightbox-prev { left: 8px; }
  .lightbox-next { right: 8px; }
  .lightbox-close { top: 16px; right: 16px; }
  .about-card { padding: 8px 22px; }
  .about-row { font-size: 14px; }
  .hero-btn { font-size: 14px; padding: 11px 18px; }
  .hero-note { font-size: 12px; gap: 8px; }
  .download-note-inner { padding: 26px 22px 22px 48px; }
  .download-note-mark { left: 12px; width: 26px; height: 26px; font-size: 12px; }
  .qr-modal-box { padding: 36px 22px 26px; }
  .qr-modal-img img { width: 180px; height: 180px; }
}

/* ---------- 减少动效 ---------- */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
  }
  html.js-ready .reveal, html.js-ready .reveal-stagger { opacity: 1 !important; transform: none !important; }
}