:root {
  color-scheme: light;
  --bg: #fff;
  --tutorial-bg: #f6f7f5;
  --surface: #fff;
  --surface-raised: #eef0ee;
  --ink: #161823;
  --muted: #687078;
  --line: rgba(22, 24, 35, 0.22);
  --accent: #4f36ff;
  --page: min(1040px, calc(100% - 56px));
}

* { box-sizing: border-box; }
html { min-width: 320px; background: var(--bg); }
body { min-height: 100vh; margin: 0; background: var(--bg); color: var(--ink); font-family: "Noto Sans SC", "Microsoft YaHei", sans-serif; line-height: 1.6; }
a { color: inherit; text-decoration: none; }
button { font: inherit; }
button:focus-visible, a:focus-visible { outline: 3px solid var(--accent); outline-offset: 4px; }

.help-header { position: sticky; z-index: 20; top: 0; width: 100%; margin: 0; border-bottom: 1px solid rgba(22, 24, 35, 0.14); background: rgba(255, 255, 255, 0.94); backdrop-filter: blur(18px); -webkit-backdrop-filter: blur(18px); }
.help-header-inner { display: grid; width: var(--page); min-height: 76px; margin-inline: auto; grid-template-columns: minmax(0, 1fr) auto minmax(0, 1fr); align-items: center; gap: 26px; }
.brand { display: inline-flex; align-items: center; gap: 11px; font-size: 15px; font-weight: 700; }
.brand img { width: 38px; height: 38px; border-radius: 9px; }
.brand i { margin-inline: 5px; color: var(--muted); font-style: normal; font-weight: 400; }
.help-header .header-actions { display: flex; align-items: center; justify-self: end; gap: 12px; }
.help-header .desktop-nav { display: flex; align-items: center; justify-self: center; gap: 28px; }
.help-header .desktop-nav a { position: relative; padding: 8px 0 7px; color: var(--muted); font-size: 14px; transition: color 160ms ease; }
.help-header .desktop-nav a:hover { color: var(--ink); }
.help-header .desktop-nav a.is-active { color: var(--ink); }
.help-header .desktop-nav a.is-active::after { position: absolute; bottom: 0; left: 50%; width: 2em; height: 4px; border-radius: 999px; background: var(--accent); box-shadow: 0 3px 7px rgba(55, 34, 215, 0.4); content: ""; transform: translateX(-50%); }
.help-header .menu-toggle { display: none; min-height: 40px; padding: 0 14px; border: 1px solid var(--line); border-radius: 999px; background: transparent; color: var(--ink); cursor: pointer; font-size: 13px; font-weight: 700; }
.help-header .mobile-menu { display: none; }
.help-header .mobile-menu[hidden] { display: none; }
.help-header .mobile-menu a.is-active { color: var(--ink); font-weight: 700; }
.help-footer a:hover { color: var(--accent); }

.button { display: inline-flex; min-height: 48px; align-items: center; justify-content: center; gap: 14px; padding: 0 20px; border: 1px solid transparent; border-radius: 999px; cursor: pointer; font-size: 14px; font-weight: 700; letter-spacing: 0.01em; transition: transform 160ms ease, background-color 160ms ease, border-color 160ms ease, color 160ms ease, box-shadow 160ms ease; }
.button:hover { transform: translateY(-2px); }
.button:active { transform: translateY(0) scale(0.98); }
.button-primary { background: var(--ink); color: #fff; box-shadow: 0 8px 18px rgba(22, 24, 35, 0.14); }
.button-primary:hover { background: var(--accent); box-shadow: 0 12px 24px rgba(79, 54, 255, 0.2); }
.help-header .button-primary { background: var(--accent); }
.help-header .button-primary:hover { background: var(--accent); }
.button-small { min-height: 40px; padding-inline: 16px; font-size: 13px; }

.help-main { width: var(--page); margin: 0 auto; padding: 54px 0 100px; }
.intro { margin: 0 auto 34px; text-align: center; }
.eyebrow { margin: 0 0 10px; color: var(--muted); font: 11px/1.5 Consolas, monospace; letter-spacing: 0.12em; }
h1, h2, h3, p { margin-top: 0; }
.intro h1 { margin-bottom: 0; font-size: clamp(30px, 4vw, 42px); line-height: 1.2; }

.selectors { display: grid; gap: 12px; padding: 22px 0 28px; border-block: 1px solid rgba(22, 24, 35, 0.2); }
.selector-row { display: grid; grid-template-columns: 76px minmax(0, 1fr); align-items: start; gap: 12px; }
.selector-row h2 { margin: 7px 0 0; font-size: 17px; font-weight: 500; white-space: nowrap; }
.selector-options { display: flex; flex-wrap: wrap; gap: 9px 10px; }
.choice { min-height: 40px; padding: 5px 15px; border: 1px solid var(--line); border-radius: 999px; background: transparent; color: var(--ink); cursor: pointer; font-size: 14px; line-height: 1.3; white-space: nowrap; transition: background-color 130ms ease, color 130ms ease, border-color 130ms ease, box-shadow 130ms ease; }
.choice:hover { border-color: var(--accent); color: var(--accent); }
.choice[aria-pressed="true"] { border-color: var(--accent); background: var(--accent); color: #fff; box-shadow: 0 8px 20px rgba(79, 54, 255, 0.18); }
.choice:active { transform: translateY(1px); }

.tutorial { width: 100%; margin: 35px 0 0; padding: 0 calc(76px + 12px); background: transparent; }
.step-list { display: grid; gap: 24px; margin: 0; padding: 0; list-style: none; }
.tutorial-section-title { margin: 22px 0 -10px; color: var(--ink); font-size: 27px; font-weight: 700 !important; line-height: 1.4; }
#tutorial-content :where(*) { font-weight: 350; }
#tutorial-content .tutorial-tip { display: block; width: 100%; max-width: 100%; margin: 0 0 12px; padding-inline: 18px; color: #d9363e; font-size: 19px; font-weight: 700; line-height: 1.55; white-space: normal; overflow-wrap: anywhere; }
.step, .step-group { display: grid; gap: 18px; }
.step-text { display: grid; gap: 12px; padding: 14px 18px; border-radius: 10px; background: var(--tutorial-bg); }
#tutorial-content .step-text h3,
#tutorial-content .step-copy,
#tutorial-content .tutorial-extractor-copy { font-family: inherit; font-size: 19px; font-weight: 350; letter-spacing: 0; line-height: 1.55; }
#tutorial-content .tutorial-download-link,
#tutorial-content .tutorial-extractor .button { font-size: 14px; font-weight: 700; letter-spacing: 0.01em; }
#tutorial-content .step-text h3 { margin: 0; color: var(--ink); }
#tutorial-content .step-copy { margin: 0; color: var(--ink); }
.step-copy code { color: var(--accent); font-family: Consolas, monospace; overflow-wrap: anywhere; }
.tutorial-download-links { display: flex; flex-wrap: wrap; gap: 8px 28px; padding-inline: 18px; }
.tutorial-download-link { flex: 0 0 auto; color: #fff; }
.tutorial-extractor { display: grid; justify-items: start; gap: 12px; padding-inline: 18px; }
.tutorial-extractor-copy { width: calc(100% + 36px); margin: 0 -18px; padding: 14px 18px; border-radius: 10px; background: var(--tutorial-bg); color: var(--ink); }
.tutorial-extractor .button { color: #fff; }

.mock-shot { position: relative; display: grid; min-height: 220px; grid-template-rows: 38px 1fr; overflow: hidden; border: 2px solid var(--line); background: var(--surface); }
.mock-toolbar { display: flex; align-items: center; gap: 7px; padding: 0 12px; border-bottom: 1px solid rgba(22, 24, 35, 0.16); background: var(--surface-raised); }
.mock-dot { width: 8px; height: 8px; border: 1px solid #687078; border-radius: 50%; }
.mock-address { min-width: 0; margin-left: 7px; padding: 3px 9px; border: 1px solid rgba(22, 24, 35, 0.2); color: var(--muted); font: 11px Consolas, monospace; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.mock-body { display: flex; align-items: center; justify-content: center; gap: 18px; padding: 24px; }
.mock-symbol { display: grid; width: 66px; height: 66px; flex: 0 0 auto; place-items: center; border: 1px solid var(--line); color: var(--accent); font: 700 21px Consolas, monospace; }
.mock-copy { display: grid; gap: 7px; max-width: 350px; }
.mock-copy strong { font-size: 16px; }
.mock-copy span { color: var(--muted); font-size: 12px; }
.mock-control { min-height: 34px; display: inline-flex; align-items: center; padding: 0 10px; border: 1px solid var(--line); color: var(--ink); font-size: 12px; }
.mock-control.active { border-color: var(--accent); color: var(--accent); }
.shot-caption { margin: 0; padding: 7px 10px; border: 1px solid var(--line); border-top: 0; color: var(--muted); font-size: 11px; }
.step-figure { margin: 0; }
.tutorial-shot img { display: block; width: 100%; height: auto; border: 0.75px solid #000; border-radius: 8px; }

.tutorial-video-frame { position: relative; width: calc(100% + 176px); margin-inline: -88px; background: #161823; }
.tutorial-video { display: block; width: 100%; height: auto; background: #161823; }
.tutorial-video-play { position: absolute; top: 50%; left: 50%; display: grid; width: 116px; height: 116px; place-items: center; padding: 0; border: 1px solid rgba(255, 255, 255, 0.3); border-radius: 50%; background: rgba(255, 255, 255, 0.7); color: var(--ink); cursor: pointer; filter: drop-shadow(0 2px 10px rgba(0, 0, 0, 0.48)); transform: translate(-50%, -50%); transition: transform 160ms ease; }
.tutorial-video-play:hover { transform: translate(-50%, -50%) scale(1.1); }
.tutorial-video-play:active { transform: translate(-50%, -50%) scale(0.96); }
.tutorial-video-play svg { display: block; width: 86px; height: 86px; opacity: 0.94; }
.tutorial-video-play[hidden] { display: none; }
.video-placeholder { display: grid; min-height: 300px; place-items: center; border: 2px solid var(--line); background: #161823; color: #fff; text-align: center; }
.video-content { display: grid; justify-items: center; gap: 12px; padding: 24px; }
.play-mark { position: relative; width: 58px; height: 58px; border: 1px solid rgba(255, 255, 255, 0.8); border-radius: 50%; }
.play-mark::after { position: absolute; top: 17px; left: 23px; width: 0; height: 0; border-block: 11px solid transparent; border-left: 16px solid var(--accent); content: ""; }
.video-content strong { font-size: 18px; }
.video-content span { color: #a6abb5; font-size: 12px; }
.video-meta { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 16px; color: var(--muted); font: 11px Consolas, monospace; }
.video-meta code { padding: 4px 7px; border: 1px solid var(--line); color: var(--ink); }

.draft-note { margin-top: 24px; padding: 12px 14px; border-left: 3px solid var(--accent); background: var(--surface-raised); color: var(--muted); font-size: 12px; }
.help-footer { width: var(--page); min-height: 68px; margin: auto; display: flex; align-items: center; justify-content: space-between; gap: 18px; border-top: 1px solid rgba(22, 24, 35, 0.16); color: var(--muted); font-size: 12px; }
.help-footer span { color: #7d838a; }

@media (max-width: 1000px) {
  .help-header-inner { display: flex; justify-content: space-between; }
  .help-header .desktop-nav { display: none; }
  .help-header .header-actions > .button { display: none; }
  .help-header .menu-toggle { display: inline-flex; align-items: center; justify-content: center; }
  .help-header .mobile-menu { display: grid; width: var(--page); margin-inline: auto; gap: 2px; padding: 8px 20px 20px; border-top: 1px solid var(--line); background: rgba(246, 247, 245, 0.96); }
  .help-header .mobile-menu[hidden] { display: none; }
  .help-header .mobile-menu a { padding: 12px 0; color: var(--muted); font-size: 15px; }
  .help-header .mobile-menu a.button { justify-self: start; margin-top: 8px; padding: 0 20px; color: #fff; font-size: 14px; }
}

@media (max-width: 640px) {
  :root { --page: calc(100% - 32px); }
  .help-header-inner { min-height: 66px; }
  .brand { gap: 8px; font-size: 13px; }
  .brand img { width: 34px; height: 34px; }
  .help-main { padding: 38px 0 70px; }
  .intro { margin-bottom: 25px; }
  .selectors { gap: 15px; padding: 18px 0 22px; }
  .selector-row { grid-template-columns: 1fr; gap: 8px; }
  .selector-row h2 { margin: 0; font-size: 15px; }
  .selector-options { gap: 8px; }
  .choice { min-height: 38px; padding-inline: 10px; font-size: 12px; }
  .tutorial { width: 100%; margin: 27px 0 0; padding: 0; }
  .tutorial-video-frame { width: calc(100% + 32px); margin-inline: -16px; }
  .tutorial-video-play { width: 88px; height: 88px; }
  .tutorial-video-play svg { width: 66px; height: 66px; }
  #tutorial-content .tutorial-tip { padding-inline: 14px; }
  .step-list { gap: 23px; }
  .step-text { padding: 12px 14px; }
  .tutorial-download-links { gap: 4px 20px; padding-inline: 14px; }
  .tutorial-extractor { padding-inline: 14px; }
  .tutorial-extractor-copy { width: calc(100% + 28px); margin-inline: -14px; padding: 12px 14px; }
  .mock-shot { min-height: 190px; }
  .mock-body { gap: 12px; padding: 16px; }
  .mock-symbol { width: 52px; height: 52px; font-size: 17px; }
  .mock-copy strong { font-size: 14px; }
  .mock-copy span { font-size: 11px; }
  .video-placeholder { min-height: 215px; }
  .help-footer { align-items: start; flex-direction: column; justify-content: center; padding: 18px 0; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { scroll-behavior: auto !important; transition-duration: 0.01ms !important; }
}