/* 外在 OuterStyle · 纸面墨字，朱红只做标点。零圆角、零投影、1px 细线。 */

:root {
  color-scheme: light;
  --paper: #F4F1EA;
  --paper-2: #E7E1D4;
  --paper-3: #DBD4C5;
  --ink: #0A0A0A;
  --ink-2: #4A4A48;
  --ink-3: #68625A;
  --hair: rgba(10, 10, 10, .14);
  --hair-2: rgba(10, 10, 10, .30);
  --control: #878075;
  --accent: #C0432A;
  --accent-text: #A8371F;
  --on-accent: #FFFFFF;

  --blk-bg: #0C0C0C;
  --blk-ink: #F2F0EA;
  --blk-ink-2: rgba(242, 240, 234, .78);
  --blk-ink-3: rgba(242, 240, 234, .62);
  --blk-hair: rgba(242, 240, 234, .20);
  --blk-accent: #E2603F;
  --blk-on-accent: #0C0C0C;

  --serif: "Iowan Old Style", "Palatino Linotype", "Songti SC", "Source Han Serif SC", "Noto Serif SC", Georgia, serif;
  --sans: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Source Han Sans SC", "Noto Sans SC", "Microsoft YaHei", system-ui, sans-serif;
  --mono: ui-monospace, "SF Mono", SFMono-Regular, Menlo, Consolas, monospace;

  --maxw: 1240px;
  --gutter: clamp(20px, 5vw, 64px);
  --step: clamp(96px, 12vw, 176px);
  --head-h: 64px;
  --ease: cubic-bezier(.22, .61, .36, 1);
  --ease-out: cubic-bezier(.16, 1, .3, 1);
  --dur: 220ms;
}

:root[data-theme="dark"] {
  color-scheme: dark;
  --paper: #0C0C0C;
  --paper-2: #1A1918;
  --paper-3: #242320;
  --ink: #F2F0EA;
  --ink-2: #B9B5AC;
  --ink-3: #918C84;
  --hair: rgba(242, 240, 234, .14);
  --hair-2: rgba(242, 240, 234, .30);
  --control: #7C766D;
  --accent: #E76B4A;
  --accent-text: #E76B4A;
  --on-accent: #0C0C0C;
  --blk-bg: #151412;
}

*, *::before, *::after { box-sizing: border-box; }
html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--head-h) + 20px);
}
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
::selection { background: var(--accent); color: var(--on-accent); }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; }
a { color: inherit; text-decoration: none; }
button { font: inherit; color: inherit; }
h1, h2, h3, p, dl, dd, dt, ol, ul, figure { margin: 0; }
ol, ul { padding: 0; list-style: none; }
img { display: block; max-width: 100%; }
.svg-defs { position: absolute; width: 0; height: 0; overflow: hidden; }

.wrap {
  width: 100%;
  max-width: var(--maxw);
  margin-inline: auto;
  padding-inline: var(--gutter);
}
.skip {
  position: absolute;
  top: 0;
  left: var(--gutter);
  z-index: 80;
  padding: 10px 16px;
  background: var(--ink);
  color: var(--paper);
  transform: translateY(-200%);
}
.skip:focus { transform: none; }

/* 顶栏 */
.progress {
  position: fixed;
  inset: 0 0 auto;
  z-index: 70;
  height: 2px;
  pointer-events: none;
}
.progress span {
  display: block;
  height: 100%;
  background: var(--accent);
  transform: scaleX(0);
  transform-origin: 0 50%;
}
.site-head {
  position: sticky;
  top: 0;
  z-index: 50;
  background: var(--paper);
  border-bottom: 1px solid transparent;
  transition: border-color var(--dur) var(--ease);
}
.site-head.is-stuck { border-bottom-color: var(--hair); }
.head-in {
  min-height: var(--head-h);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}
.brand {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 2px;
  line-height: 1.1;
}
.brand-en {
  font-family: var(--serif);
  font-size: 19px;
  letter-spacing: -.01em;
  color: var(--ink);
  line-height: 1.1;
}
.brand-cn {
  color: var(--ink-3);
  font-size: 10px;
  letter-spacing: .17em;
  line-height: 1.2;
}
.head-actions { display: flex; align-items: center; gap: 20px; }
.icon-btn {
  width: 36px;
  height: 36px;
  margin-right: -8px;
  display: grid;
  place-items: center;
  border: 0;
  background: transparent;
  color: var(--ink-2);
  cursor: pointer;
  transition: color var(--dur) var(--ease);
}
.icon-btn:hover { color: var(--accent-text); }
.icon-btn svg {
  width: 18px;
  height: 18px;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.5;
  stroke-linecap: round;
  stroke-linejoin: round;
}
.ico-sun { display: none; }
:root[data-theme="dark"] .ico-sun { display: block; }
:root[data-theme="dark"] .ico-moon { display: none; }
.head-dl {
  min-height: 36px;
  display: inline-flex;
  align-items: center;
  gap: 3px;
  border-bottom: 1px solid var(--ink);
  font-size: 13px;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}
.head-dl:hover { color: var(--accent-text); border-color: var(--accent-text); }
.head-dl span { transition: transform var(--dur) var(--ease); }
.head-dl:hover span { transform: translateY(2px); }

/* 按钮 */
.btn {
  min-height: 52px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 0 26px;
  border: 1px solid transparent;
  font-size: 14px;
  font-weight: 500;
  line-height: 1;
  cursor: pointer;
  transition: background-color var(--dur) var(--ease), color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}
.btn-solid { background: var(--ink); color: var(--paper); border-color: var(--ink); }
.btn-solid:hover { background: var(--accent); color: var(--on-accent); border-color: var(--accent); }
.btn-paper { background: var(--blk-ink); color: var(--blk-bg); border-color: var(--blk-ink); }
.btn-paper:hover { background: var(--blk-accent); color: var(--blk-on-accent); border-color: var(--blk-accent); }
.arr { display: inline-block; transition: transform var(--dur) var(--ease); }
.btn:hover .arr { transform: translateX(4px); }
.btn-paper:hover .arr { transform: translateY(3px); }
.quiet-link {
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  color: var(--ink-2);
  font-size: 14px;
  border-bottom: 1px solid var(--hair-2);
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}
.quiet-link:hover { color: var(--ink); border-color: var(--ink); }
.meta {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: .03em;
  color: var(--ink-3);
}

/* 首屏 */
.cover {
  min-height: calc(100vh - var(--head-h));
  min-height: calc(100svh - var(--head-h));
  display: flex;
  flex-direction: column;
}
.cover-main {
  flex: 1;
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding-block: clamp(56px, 10vh, 120px) clamp(48px, 8vh, 96px);
}
.cover-title {
  font-family: var(--serif);
  font-weight: 400;
  font-size: clamp(48px, 10.2vw, 142px);
  line-height: 1.02;
  letter-spacing: -.01em;
  text-wrap: balance;
}
.cover-title .line { display: block; }
.dot { color: var(--accent); }
.cover-sub {
  margin-top: clamp(24px, 3vw, 34px);
  color: var(--ink-2);
  font-size: clamp(16px, 1.4vw, 18px);
}
.cover-actions {
  margin-top: 36px;
  display: flex;
  align-items: center;
  gap: 28px;
  flex-wrap: wrap;
}
.cover-foot {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  border-top: 1px solid var(--hair);
  padding-block: 22px 28px;
}
.scroll-cue { display: flex; align-items: center; gap: 6px; }

/* 试一课 */
.kicker {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 12px;
  color: var(--ink-3);
}
.kicker-rule { width: 22px; height: 1px; background: var(--accent); flex: none; }
.lesson {
  background: var(--paper-2);
  border-top: 1px solid var(--hair);
  border-bottom: 1px solid var(--hair);
  padding-block: clamp(64px, 8vw, 112px);
}
.lesson-in {
  display: grid;
  grid-template-columns: minmax(0, 4fr) minmax(0, 7fr);
  gap: clamp(32px, 5vw, 72px);
  align-items: start;
}
.lesson-left { min-width: 0; }
.lesson-head { max-width: 760px; }
.lesson-head h2 {
  margin-top: 18px;
  font-family: var(--serif);
  font-weight: 400;
  font-size: clamp(38px, 4.2vw, 62px);
  line-height: 1.06;
  letter-spacing: -.01em;
}
.lesson-head h2 span { display: block; }
.lesson-sub { margin-top: 16px; color: var(--ink-2); font-size: 16px; }

.pair {
  grid-column: 2;
  display: grid;
  grid-template-columns: 1fr 1fr;
  border: 1px solid var(--control);
}
.look {
  position: relative;
  display: flex;
  flex-direction: column;
  padding: clamp(16px, 2.4vw, 24px);
  border: 0;
  background: transparent;
  text-align: left;
  cursor: pointer;
  transition: background-color var(--dur) var(--ease), opacity var(--dur) var(--ease);
}
.look + .look { border-left: 1px solid var(--control); }
@media (hover: hover) {
  .look:hover { background: rgba(244, 241, 234, .45); }
  :root[data-theme="dark"] .look:hover { background: rgba(12, 12, 12, .28); }
}
.look[aria-pressed="true"] {
  outline: 2px solid var(--accent);
  outline-offset: -2px;
  background: var(--paper);
}
.look-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  min-height: 18px;
}
.look-id { font-family: var(--mono); font-size: 12px; color: var(--ink-2); }
.look-state {
  font-size: 11px;
  color: var(--accent-text);
  opacity: 0;
  transition: opacity var(--dur) var(--ease);
}
.look[aria-pressed="true"] .look-state { opacity: 1; }
.look-art {
  display: block;
  width: min(100%, 300px);
  margin: 8px auto 0;
  aspect-ratio: 240 / 340;
  background: #F4F1EA;
}
.look-art svg { width: 100%; height: 100%; display: block; }
.look-names {
  display: flex;
  flex-wrap: wrap;
  gap: 5px 16px;
  margin-top: 14px;
  font-family: var(--mono);
  font-size: 11px;
  color: var(--ink-3);
}
.look-names span { display: inline-flex; align-items: center; gap: 6px; }
.sw { display: inline-block; width: 7px; height: 7px; background: var(--piece-1); }
.sw-2 { background: var(--piece-2); }
.sw-3 { background: var(--piece-3); }

.verdict {
  scroll-margin-top: calc(var(--head-h) + 20px);
  display: grid;
  grid-template-rows: 0fr;
  opacity: 0;
  margin-top: 0;
  transition: grid-template-rows .52s var(--ease-out), opacity .34s var(--ease), margin-top .52s var(--ease-out);
}
.verdict.is-open {
  grid-template-rows: 1fr;
  opacity: 1;
  margin-top: clamp(36px, 5vw, 56px);
}
.verdict-clip { overflow: hidden; min-height: 0; }
.verdict-in {
  padding-top: 24px;
  border-top: 1px solid var(--hair-2);
}
.verdict-k { margin-bottom: 12px; font-size: 12px; color: var(--ink-3); }
.verdict-text {
  font-family: var(--serif);
  font-size: clamp(20px, 1.9vw, 26px);
  line-height: 1.55;
}
.roles {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 18px;
  margin-top: 18px;
  font-size: 12px;
  color: var(--ink-2);
}
.roles li { display: flex; align-items: center; gap: 7px; }
.roles .sw { width: 9px; height: 9px; }
.roles span { color: var(--ink-3); }
.verdict-cta { min-height: 46px; margin-top: 22px; padding-inline: 20px; font-size: 13px; }

.js .reveal {
  opacity: 0;
  transform: translateY(12px);
  transition: opacity .7s var(--ease-out), transform .7s var(--ease-out);
}
.js .reveal.in { opacity: 1; transform: none; }

/* 它怎么用 */
.app { padding-block: clamp(80px, 9vw, 136px); }
.app-head { max-width: 820px; }
.app-head h2 {
  margin-top: 14px;
  text-wrap: balance;
  font-family: var(--serif);
  font-weight: 400;
  font-size: clamp(32px, 4.6vw, 60px);
  line-height: 1.1;
  letter-spacing: -.01em;
}
.preview {
  display: grid;
  grid-template-columns: minmax(0, 6fr) minmax(0, 5fr);
  gap: clamp(40px, 6vw, 96px);
  align-items: start;
  margin-top: clamp(36px, 5vw, 56px);
}
.preview-steps { border-top: 1px solid var(--hair); }
.pstep {
  display: grid;
  grid-template-columns: 3em minmax(0, 1fr);
  grid-template-areas: "k t" "k d";
  align-items: start;
  width: 100%;
  padding: 20px 0 20px 18px;
  border: 0;
  border-bottom: 1px solid var(--hair);
  background: transparent;
  text-align: left;
  cursor: pointer;
  transition: background-color var(--dur) var(--ease), box-shadow var(--dur) var(--ease);
}
.pstep:hover { background: rgba(244, 241, 234, .42); }
:root[data-theme="dark"] .pstep:hover { background: rgba(12, 12, 12, .28); }
.pstep.is-active { box-shadow: inset 2px 0 0 var(--accent); }
.pstep-k {
  grid-area: k;
  padding-top: 4px;
  font-family: var(--mono);
  font-size: 11px;
  color: var(--ink-3);
}
.pstep.is-active .pstep-k { color: var(--accent-text); }
.pstep-t { grid-area: t; color: var(--ink-2); font-family: var(--serif); font-size: clamp(22px, 2vw, 28px); line-height: 1.2; transition: color var(--dur) var(--ease); }
.pstep.is-active .pstep-t { color: var(--ink); }
.pstep-d { grid-area: d; margin-top: 6px; color: var(--ink-3); font-size: 13px; line-height: 1.7; transition: color var(--dur) var(--ease); }
.pstep.is-active .pstep-d { color: var(--ink-2); }
.preview-stage {
  position: relative;
  width: min(100%, 300px);
  aspect-ratio: 720 / 1050;
  justify-self: center;
  border: 1px solid var(--control);
  background: var(--paper-2);
}
.preview-frame {
  position: absolute;
  inset: 0;
  opacity: 0;
  transition: opacity .32s var(--ease);
}
.preview-frame.is-active { opacity: 1; }
.preview-frame img { width: 100%; height: 100%; object-fit: cover; }

/* 下载 */
.download {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  min-height: 100svh;
  background: var(--blk-bg);
  color: var(--blk-ink);
  border-top: 1px solid var(--blk-hair);
}
.download ::selection { background: var(--blk-accent); color: var(--blk-on-accent); }
.download :focus-visible { outline-color: var(--blk-accent); }
.download-main {
  flex: 1;
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding-block: clamp(88px, 13vh, 160px);
}
.download-main h2 {
  font-family: var(--serif);
  font-weight: 400;
  font-size: clamp(44px, 7.6vw, 104px);
  line-height: 1.03;
  letter-spacing: -.015em;
  text-wrap: balance;
}
.download-meta {
  margin-top: 22px;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: .03em;
  color: var(--blk-ink-3);
}
.download .btn-paper {
  min-height: 58px;
  margin-top: 34px;
  padding-inline: 36px;
  font-size: 15px;
}
.download-note { margin-top: 18px; font-size: 12px; color: var(--blk-ink-3); }
.install {
  max-width: 680px;
  margin-top: clamp(48px, 7vh, 72px);
  border-top: 1px solid var(--blk-hair);
}
.install summary {
  list-style: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding-block: 16px;
  font-size: 12px;
  color: var(--blk-ink-2);
  cursor: pointer;
}
.install summary::-webkit-details-marker { display: none; }
.install summary::after {
  content: "+";
  font-family: var(--mono);
  font-size: 16px;
  line-height: 1;
  color: var(--blk-ink-3);
}
.install[open] summary::after { content: "−"; }
.install-body { padding-bottom: 8px; }
.install-body p {
  max-width: 38em;
  font-size: 12px;
  line-height: 1.75;
  color: var(--blk-ink-2);
}
.install-body .hash {
  margin-top: 14px;
  font-family: var(--mono);
  font-size: 11px;
  color: var(--blk-ink-3);
  overflow-wrap: anywhere;
}

/* 页脚 */
.site-foot {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 12px 32px;
  padding-block: 28px 36px;
  border-top: 1px solid var(--blk-hair);
}
.foot-brand {
  display: flex;
  flex-direction: column;
  gap: 2px;
  line-height: 1.1;
  color: var(--blk-ink);
}
.foot-en {
  font-family: var(--serif);
  font-size: 18px;
  letter-spacing: -.01em;
  color: var(--blk-ink);
}
.foot-cn { font-family: var(--sans); font-size: 10px; letter-spacing: .16em; color: var(--blk-ink-3); }
.foot-links {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 20px;
  justify-self: end;
  font-size: 12px;
  color: var(--blk-ink-2);
}
.foot-links a { padding-bottom: 1px; border-bottom: 1px solid transparent; }
.foot-links a:hover { color: var(--blk-ink); border-color: var(--blk-ink); }
.foot-copy { grid-column: 1 / -1; font-size: 11px; color: var(--blk-ink-3); }

@media (max-width: 900px) {
  .cover-title { font-size: clamp(46px, 11.5vw, 100px); }
  .lesson-in { display: flex; flex-direction: column; }
  .lesson-left { display: contents; }
  .lesson-head { order: 1; }
  .pair { order: 2; grid-column: auto; margin-top: 32px; }
  .verdict { order: 3; }
}
@media (max-width: 720px) {
  .head-actions { gap: 14px; }
  .cover-foot { padding-block: 18px 22px; }
  .look { padding: 12px; }
  .look-art { width: 100%; margin-top: 6px; }
  .look-names { gap: 4px 10px; }
  .site-foot { grid-template-columns: 1fr; }
  .foot-links { justify-self: start; }
  .preview { grid-template-columns: 1fr; gap: 24px; }
  .preview-steps {
    display: flex;
    border-top: 0;
    border-bottom: 1px solid var(--hair);
    overflow-x: auto;
    scrollbar-width: none;
  }
  .preview-steps::-webkit-scrollbar { display: none; }
  .pstep {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 12px 8px;
    border-bottom: 0;
    text-align: center;
  }
  .pstep.is-active { box-shadow: inset 0 -2px 0 var(--accent); }
  .pstep-k { display: none; }
  .pstep-t { font-size: 16px; }
  .pstep-d { display: none; }
  .preview-stage { width: min(100%, 300px); }
}
@media (max-width: 340px) {
  .cover-title { font-size: 44px; }
}
@media (max-width: 560px) {
  .cover-actions { flex-direction: column; align-items: stretch; gap: 8px; }
  .cover-actions .btn { width: 100%; }
  .quiet-link { justify-content: center; border-bottom: 0; }
  .head-dl { font-size: 12px; }
  .download .btn-paper { width: 100%; }
  .verdict-cta { width: 100%; }
  .download-main h2 { font-size: clamp(40px, 12vw, 64px); }
  .install { margin-top: 44px; }
}

@keyframes rise {
  from { opacity: 0; transform: translateY(16px); }
  to { opacity: 1; transform: none; }
}
.js .cover-title { animation: rise .8s var(--ease-out) both; }
.js .cover-sub { animation: rise .8s .08s var(--ease-out) both; }
.js .cover-actions { animation: rise .8s .16s var(--ease-out) both; }
.js .cover-foot { animation: rise .8s .24s var(--ease-out) both; }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: .001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .001ms !important;
  }
  .js .reveal { opacity: 1; transform: none; }
}