:root {
  --ink: #17191b;
  --ink-soft: #4e5659;
  --paper: #f7f8f5;
  --line: #d9ddda;
  --coral: #e65d50;
  --coral-dark: #c9473b;
  --mint: #82c4b1;
  --sun: #edc95e;
  --blue: #b5dbe5;
  --white: #ffffff;
  --radius: 6px;
  --content-width: 1120px;
}

* { box-sizing: border-box; }

html { background: var(--paper); scroll-behavior: smooth; }

body {
  min-width: 320px;
  margin: 0;
  padding-bottom: 92px;
  color: var(--ink);
  background: var(--paper);
  font-family: "Microsoft YaHei", "PingFang SC", system-ui, sans-serif;
  font-size: 16px;
  line-height: 1.5;
  letter-spacing: 0;
}
main { padding-bottom: 90px; }
.site-message { position: fixed; z-index: 100; top: 12px; right: 12px; max-width: min(360px, calc(100% - 24px)); padding: 10px 12px; color: #75342e; border: 1px solid #e9b2ad; border-radius: 4px; background: #fff4f2; font-size: 13px; }

button, input { font: inherit; }
button { cursor: pointer; }
button:focus-visible, a:focus-visible, video:focus-visible { outline: 3px solid var(--sun); outline-offset: 3px; }

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  height: 58px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 clamp(18px, 5vw, 64px);
  color: var(--white);
  background: var(--ink);
}

.brand { display: inline-flex; align-items: center; gap: 9px; color: inherit; font-weight: 700; text-decoration: none; }
.brand-logo { display: block; width: 34px; height: 34px; flex: 0 0 34px; border-radius: 4px; background: #000; object-fit: contain; }
.header-meta { color: #d9dfdc; font-size: 13px; }

.page-tabs {
  position: sticky;
  top: 58px;
  z-index: 18;
  display: block;
  min-height: 94px;
  padding: 7px clamp(12px, 4vw, 48px) 8px;
  overflow-x: auto;
  border-bottom: 1px solid var(--line);
  background: #eef7f5;
  scrollbar-width: none;
}
.page-tabs::-webkit-scrollbar { display: none; }

.tabs-guide {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  width: min(100%, var(--content-width));
  margin: 0 auto 7px;
}
.tabs-guide strong { color: var(--ink); font-size: 14px; }
.tabs-guide span { color: #526460; font-size: 12px; }
.tabs-list { display: flex; gap: 8px; width: min(100%, var(--content-width)); margin: 0 auto; }

.tab-button {
  flex: 0 0 auto;
  min-width: 126px;
  height: 46px;
  display: grid;
  grid-template-columns: 24px 1fr auto;
  align-items: center;
  gap: 7px;
  padding: 0 10px;
  color: var(--tab-text, var(--ink));
  border: 1px solid var(--tab-border, #c9d3d0);
  border-radius: var(--radius);
  background: var(--tab-bg, var(--white));
  font-size: 15px;
  text-align: left;
  font-weight: 700;
}
.tab-button span { color: #b14a42; font-size: 11px; font-weight: 800; }
.tab-button b { font-weight: 800; }
.tab-button i { color: #60706c; font-size: 11px; font-style: normal; font-weight: 700; }
.tab-button:not(.is-active):hover { border-color: var(--coral); background: #fff !important; }
.tab-button.is-active { color: var(--tab-active-text, var(--white)); border-color: var(--tab-active-bg, var(--coral)); background: var(--tab-active-bg, var(--coral)); box-shadow: inset 0 -3px 0 var(--tab-active-shadow, #c8473d); }
.tab-button.is-active span, .tab-button.is-active i { color: #fff3d4; }

.page-panel { display: none; }
.page-panel[hidden] { display: none !important; }
.page-panel.is-active { display: block; animation: panel-in 260ms ease-out; }
@keyframes panel-in { from { opacity: 0; transform: translateY(5px); } to { opacity: 1; transform: translateY(0); } }

.hero {
  position: relative;
  isolation: isolate;
  min-height: min(58svh, 580px);
  overflow: hidden;
  color: var(--white);
  background: var(--ink);
}
.hero-image { position: absolute; z-index: -2; width: 100%; height: 100%; object-fit: cover; object-position: center 12%; }
.hero-shade { position: absolute; z-index: -1; inset: 0; background: rgba(12, 14, 16, 0.56); }
.hero-content { width: min(100% - 40px, var(--content-width)); margin: 0 auto; padding-top: clamp(120px, 26vh, 230px); padding-bottom: 42px; }

.eyebrow { margin: 0 0 11px; color: var(--sun); font-size: 13px; font-weight: 700; }
.eyebrow-dark { color: #b03d35; }
h1, h2, h3, p { margin-top: 0; overflow-wrap: anywhere; }
h1 { max-width: 720px; margin-bottom: 14px; font-size: clamp(35px, 6vw, 68px); line-height: 1.13; font-weight: 800; }
h2 { font-size: clamp(25px, 4vw, 38px); line-height: 1.25; }
.hero-copy { max-width: 480px; margin-bottom: 25px; color: #e7e9e6; font-size: clamp(15px, 2vw, 18px); }

.primary-action, .purchase-button, .save-qr-button, .open-wechat-button {
  min-height: 48px;
  padding: 0 20px;
  border: 0;
  border-radius: var(--radius);
  color: var(--white);
  background: var(--coral);
  font-weight: 800;
}
.primary-action:hover, .purchase-button:hover, .save-qr-button:hover { background: var(--coral-dark); }
.primary-action span { margin-left: 8px; }

.section { width: min(100% - 40px, var(--content-width)); margin: 0 auto; padding: clamp(44px, 8vw, 90px) 0; }
.section-heading { max-width: 640px; margin-bottom: 29px; }
.section-heading h2 { margin-bottom: 0; }

.overview-section { background: var(--paper); }
.preview-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 14px; }
.preview-tile { position: relative; aspect-ratio: 4 / 5; overflow: hidden; padding: 0; color: var(--white); border: 0; border-radius: var(--radius); background: var(--ink); text-align: left; }
.preview-tile img { width: 100%; height: 100%; object-fit: cover; transition: transform 240ms ease; }
.preview-tile:hover img { transform: scale(1.035); }
.preview-tile span { position: absolute; right: 12px; bottom: 10px; left: 12px; text-shadow: 0 1px 8px #000; font-weight: 800; }

.process-section { width: 100%; padding-right: max(20px, calc((100% - var(--content-width)) / 2)); padding-left: max(20px, calc((100% - var(--content-width)) / 2)); background: var(--mint); }
.process-section .section-heading { margin-right: auto; margin-left: auto; }
.process-list { width: min(100%, var(--content-width)); display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 28px; margin: 0 auto; padding: 0; list-style: none; }
.process-list li { border-top: 2px solid var(--ink); padding-top: 14px; }
.process-list span, .detail-number { display: block; margin-bottom: 13px; color: #176b5b; font-size: 14px; font-weight: 800; }
.process-list strong { display: block; margin-bottom: 7px; font-size: 20px; }
.process-list p { margin-bottom: 0; color: #273f3a; }

.page-intro { padding-bottom: 28px; }
.page-intro h1 { max-width: 760px; margin-bottom: 12px; color: var(--ink); font-size: clamp(34px, 5vw, 58px); }
.page-intro p:last-child { max-width: 540px; margin-bottom: 0; color: var(--ink-soft); }

.video-list { width: min(100% - 40px, var(--content-width)); display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 18px; margin: 0 auto; padding-bottom: clamp(44px, 8vw, 90px); }
.video-entry { border-top: 2px solid var(--ink); padding-top: 12px; }
.video-card { position: relative; display: block; width: 100%; aspect-ratio: 9 / 15; margin: 0 0 13px; padding: 0; overflow: hidden; color: var(--white); border: 0; border-radius: var(--radius); background: #0a0a0a; text-align: left; }
.video-card img { display: block; width: 100%; height: 100%; object-fit: cover; }
.video-card::after { position: absolute; inset: 0; content: ""; background: linear-gradient(180deg, rgba(0, 0, 0, 0.04), rgba(0, 0, 0, 0.42)); }
.video-card-play { position: absolute; z-index: 1; top: 50%; left: 50%; display: grid; width: 54px; height: 54px; place-items: center; padding-left: 4px; border: 2px solid rgba(255, 255, 255, 0.82); border-radius: 50%; background: rgba(10, 12, 14, 0.66); font-size: 20px; transform: translate(-50%, -50%); }
.video-card-hint { position: absolute; z-index: 1; right: 12px; bottom: 10px; font-size: 13px; font-weight: 800; }
.video-card:hover img { transform: scale(1.025); }
.video-index { margin-bottom: 4px; color: var(--coral-dark); font-size: 13px; font-weight: 700; }
.video-entry h2 { margin-bottom: 0; font-size: 20px; }

.media-masonry { width: min(100% - 40px, var(--content-width)); columns: 3 230px; column-gap: 14px; margin: 0 auto; padding-bottom: clamp(44px, 8vw, 90px); }
.gallery-item { display: inline-block; width: 100%; margin: 0 0 14px; padding: 0; overflow: hidden; border: 0; border-radius: var(--radius); background: var(--ink); vertical-align: top; }
.gallery-item img { display: block; width: 100%; height: auto; transition: transform 240ms ease; }
.gallery-item:hover img { transform: scale(1.02); }

.chat-grid { width: min(100% - 40px, var(--content-width)); display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 13px; margin: 0 auto; padding-bottom: clamp(44px, 8vw, 90px); }
.chat-shot { padding: 0; overflow: hidden; border: 1px solid var(--line); border-radius: var(--radius); background: var(--white); }
.chat-shot img { display: block; width: 100%; height: auto; }

.detail-list { width: min(100% - 40px, var(--content-width)); display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 1px; margin: 0 auto; border: 1px solid var(--line); background: var(--line); }
.detail-list article { min-height: 210px; padding: clamp(24px, 5vw, 46px); background: var(--white); }
.detail-list article:nth-child(2) { background: var(--blue); }
.detail-list article:nth-child(3) { background: var(--sun); }
.detail-list article:nth-child(4) { background: var(--mint); }
.detail-list h2 { margin-bottom: 10px; font-size: clamp(23px, 3vw, 32px); }
.detail-list p { margin-bottom: 0; color: #3f4848; }
.final-section { text-align: center; }
.final-section h2 { margin-bottom: 22px; }

.purchase-bar {
  position: fixed;
  z-index: 25;
  right: 0;
  bottom: 0;
  left: 0;
  display: grid;
  grid-template-columns: minmax(190px, 280px) 134px;
  align-items: center;
  justify-content: center;
  gap: clamp(18px, 8vw, 240px);
  min-height: 76px;
  padding: 12px 20px;
  border-top: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.96);
  backdrop-filter: blur(8px);
  transition: transform 220ms ease;
}
.purchase-bar.is-hidden { transform: translateY(110%); pointer-events: none; }
.purchase-bar.is-visible { transform: translateY(0); }
.purchase-bar div { display: flex; align-items: baseline; gap: 10px; }
.purchase-bar span { color: var(--ink-soft); font-size: 13px; }
.purchase-bar strong { color: var(--ink); font-size: 17px; }
.purchase-button { width: 100%; min-width: 0; }

dialog { border: 0; }
.join-dialog { width: min(100% - 32px, 760px); padding: 0; border-radius: 8px; color: var(--ink); background: var(--white); box-shadow: 0 18px 60px rgba(0, 0, 0, 0.25); }
.join-dialog::backdrop, .media-dialog::backdrop, .video-dialog::backdrop { background: rgba(15, 18, 19, 0.72); }
.join-dialog[open] { display: block; animation: dialog-in 180ms ease-out; }
@keyframes dialog-in { from { opacity: 0; transform: translateY(12px); } to { opacity: 1; transform: translateY(0); } }
.join-dialog > * { margin-right: 24px; margin-left: 24px; }
.dialog-topline { display: flex; align-items: center; justify-content: space-between; margin-top: 23px; margin-bottom: 4px; }
.dialog-topline .eyebrow { margin: 0; }
.icon-button { display: grid; width: 36px; height: 36px; place-items: center; padding: 0; color: var(--ink); border: 1px solid var(--line); border-radius: 50%; background: var(--white); font-size: 24px; line-height: 1; }
.icon-button:hover { background: #f0f2ef; }
.join-dialog-content { display: grid; grid-template-columns: minmax(0, 310px) minmax(0, 1fr); gap: 30px; align-items: center; margin-top: 14px; margin-bottom: 24px; min-width: 0; }
.join-qr-wrap { display: grid; min-width: 0; place-items: center; min-height: 310px; padding: 10px; border: 1px solid var(--line); border-radius: var(--radius); background: #f7f8f5; }
.join-qr { display: block; width: min(100%, 282px); max-width: 100%; height: auto; border-radius: 3px; }
.join-instructions { min-width: 0; }
.join-instructions h2 { margin: 0 0 12px; font-size: 28px; line-height: 1.24; }
.join-instructions > p { margin-bottom: 17px; color: var(--ink-soft); font-size: 14px; }
.join-instructions .join-group-label { display: inline-flex; align-items: center; min-height: 42px; margin: 0 0 10px; padding: 4px 13px; color: #fff; border-left: 5px solid var(--sun); border-radius: 4px; background: var(--coral); font-size: 25px; font-weight: 900; line-height: 1; }
.join-steps { margin: 0 0 22px; padding-left: 20px; color: #30383a; font-size: 14px; }
.join-steps li + li { margin-top: 6px; }
.join-actions { display: flex; gap: 10px; }
.save-qr-button, .open-wechat-button { display: inline-grid; min-height: 46px; place-items: center; padding: 0 15px; border-radius: var(--radius); text-decoration: none; font-size: 14px; }
.open-wechat-button { color: #173f2a; border: 1px solid #74b78d; background: #e4f4e9; font-weight: 800; }
.open-wechat-button:hover { background: #cdebd6; }

.media-dialog { width: min(100% - 24px, 1100px); max-width: 1100px; max-height: calc(100svh - 28px); padding: 46px 12px 12px; overflow: auto; border-radius: 8px; background: #111315; }
.media-dialog .icon-button { position: absolute; top: 8px; right: 8px; color: var(--white); border-color: #53595a; background: #1d2223; }
.media-dialog img { display: block; width: auto; max-width: 100%; max-height: calc(100svh - 82px); margin: 0 auto; object-fit: contain; }
.video-dialog { width: min(100% - 24px, 760px); max-width: 760px; padding: 46px 12px 12px; overflow: hidden; border-radius: 8px; background: #111315; }
.video-dialog .icon-button { position: absolute; z-index: 1; top: 8px; right: 8px; color: var(--white); border-color: #53595a; background: #1d2223; }
.video-dialog-body { display: grid; place-items: center; min-height: 180px; }
.video-dialog-body video { display: block; width: auto; max-width: 100%; max-height: calc(100svh - 92px); background: #000; }

@media (max-width: 720px) {
  body { padding-bottom: 72px; }
  main { padding-bottom: 74px; }
  .site-header { height: 48px; padding: 0 14px; }
  .brand-logo { width: 30px; height: 30px; flex-basis: 30px; }
  .header-meta { font-size: 12px; }
  .page-tabs { top: 48px; min-height: 124px; padding: 6px 10px 7px; }
  .tabs-guide { margin-bottom: 5px; }
  .tabs-guide strong { font-size: 13px; }
  .tabs-guide span { font-size: 11px; }
  .tabs-list { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 7px; }
  .tab-button { min-width: 0; width: 100%; height: 36px; padding: 0 7px; grid-template-columns: 17px 1fr auto; gap: 2px; font-size: 12px; }
  .tab-button span { font-size: 10px; }
  .tab-button i { font-size: 10px; }
  .hero { min-height: 70svh; }
  .hero-content { padding-top: 43svh; }
  .preview-grid { gap: 8px; }
  .preview-tile span { right: 8px; bottom: 7px; left: 8px; font-size: 13px; }
  .process-list { grid-template-columns: 1fr; gap: 24px; }
  .process-list li { display: grid; grid-template-columns: 42px 1fr; column-gap: 12px; }
  .process-list span { grid-row: span 2; margin: 1px 0 0; }
  .process-list strong { margin-bottom: 3px; }
  .process-list p { grid-column: 2; }
  .video-list { grid-template-columns: 1fr; gap: 33px; }
  .video-entry { display: block; }
  .video-card { max-height: 62svh; aspect-ratio: 9 / 14; }
  .chat-grid {
    width: 100%;
    display: grid;
    grid-auto-flow: column;
    grid-auto-columns: minmax(252px, 74vw);
    grid-template-columns: none;
    gap: 12px;
    padding: 0 20px 44px;
    overflow-x: auto;
    overscroll-behavior-inline: contain;
    scroll-snap-type: inline mandatory;
    scrollbar-width: none;
  }
  .chat-grid::-webkit-scrollbar { display: none; }
  .chat-shot { scroll-snap-align: start; }
  .detail-list { grid-template-columns: 1fr; }
  .detail-list article { min-height: 162px; }
  .page-intro h1 { font-size: 32px; }
  .purchase-bar { grid-template-columns: minmax(0, 1fr) 116px; min-height: 62px; gap: 8px; padding: 7px 12px; justify-content: normal; }
  .purchase-bar div { min-width: 0; gap: 6px; white-space: nowrap; }
  .purchase-bar span { font-size: 12px; }
  .purchase-bar strong { font-size: 14px; }
  .purchase-button { min-width: 0; width: 116px; min-height: 48px; padding: 0 10px; }
  .join-dialog { width: min(calc(100vw - 28px), 460px); min-width: 0; max-width: calc(100vw - 28px); max-height: calc(100svh - 18px); overflow: hidden; }
  .join-dialog > * { margin-right: 12px; margin-left: 12px; }
  .dialog-topline { margin-top: 11px; margin-bottom: 3px; }
  .dialog-topline .eyebrow { font-size: 13px; }
  .dialog-topline .icon-button { width: 31px; height: 31px; font-size: 21px; }
  .join-dialog-content { grid-template-columns: minmax(0, 132px) minmax(0, 1fr); gap: 12px; align-items: start; margin-top: 4px; margin-bottom: 12px; }
  .join-qr-wrap { min-height: 0; padding: 4px; }
  .join-qr { width: 100%; max-width: 132px; height: auto; }
  .join-instructions h2 { margin-bottom: 7px; font-size: 20px; line-height: 1.2; }
  .join-instructions .join-group-label { min-height: 31px; margin-bottom: 6px; padding: 3px 8px; border-left-width: 4px; font-size: 20px; }
  .join-steps { margin: 0 0 10px; padding-left: 15px; font-size: 11px; line-height: 1.45; }
  .join-steps li + li { margin-top: 3px; }
  .join-actions { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); }
  .save-qr-button, .open-wechat-button { min-width: 0; min-height: 40px; padding: 0 5px; white-space: nowrap; font-size: 12px; }
}

@media (min-width: 721px) {
  .page-tabs { justify-content: center; }
}