/* ==========================================================================
   AI 翻译助手 · 官方宣传站样式
   设计基线：石墨黑底 + 单一电蓝强调色 + 等宽字标注，避免模板化渐变堆叠
   ========================================================================== */

:root {
  color-scheme: dark;

  /* 背景层次 */
  --bg: #07090d;
  --bg-2: #090c11;
  --surface: #0e1218;
  --surface-2: #141922;
  --surface-3: #1b212b;

  /* 描边 */
  --line: rgba(255, 255, 255, 0.075);
  --line-2: rgba(255, 255, 255, 0.14);

  /* 文本 */
  --text: #eef1f6;
  --text-2: #a8b1be;
  --text-3: #7f8896;

  /* 强调色 */
  --accent: #4d8dff;
  --accent-hi: #74a6ff;
  --accent-ink: #05080f;
  --accent-soft: rgba(77, 141, 255, 0.12);
  --accent-line: rgba(77, 141, 255, 0.34);
  --mint: #3ddc97;
  --amber: #ffb457;
  --rose: #ff7a76;

  /* 形状与节奏 */
  --r-s: 8px;
  --r-m: 12px;
  --r-l: 18px;
  --r-xl: 24px;
  --wrap: 1180px;
  --pad: clamp(20px, 5vw, 44px);
  --sec-y: clamp(72px, 10vw, 132px);

  --shadow-l: 0 34px 70px -28px rgba(0, 0, 0, 0.85);
  --shadow-m: 0 18px 40px -22px rgba(0, 0, 0, 0.8);

  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", Roboto, Helvetica, Arial, sans-serif;
  --mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas,
    "Liberation Mono", monospace;

  --ease: cubic-bezier(0.22, 1, 0.36, 1);
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

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

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.7;
  letter-spacing: 0.01em;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

h1,
h2,
h3,
p,
dl,
dd,
figure {
  margin: 0;
}

ul,
ol {
  margin: 0;
  padding: 0;
  list-style: none;
}

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

button {
  font: inherit;
  color: inherit;
}

code,
.mono {
  font-family: var(--mono);
  font-size: 0.9em;
  letter-spacing: 0;
}

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
  border-radius: 4px;
}

.wrap {
  width: 100%;
  max-width: var(--wrap);
  margin: 0 auto;
  padding-inline: var(--pad);
}

.wrap--narrow {
  max-width: 880px;
}

.skip-link {
  position: absolute;
  left: 16px;
  top: -60px;
  z-index: 300;
  padding: 10px 16px;
  background: var(--accent);
  color: var(--accent-ink);
  border-radius: var(--r-s);
  font-weight: 700;
  transition: top 0.18s var(--ease);
}

.skip-link:focus {
  top: 12px;
}

/* ------------------------------------------------------------------ 进度条 */
.progress {
  position: fixed;
  inset: 0 0 auto 0;
  height: 2px;
  z-index: 200;
  background: transparent;
}

.progress__bar {
  display: block;
  height: 100%;
  width: 100%;
  transform: scaleX(0);
  transform-origin: 0 50%;
  background: var(--accent);
}

/* -------------------------------------------------------------------- 导航 */
.nav {
  position: sticky;
  top: 0;
  z-index: 120;
  background: rgba(7, 9, 13, 0.72);
  backdrop-filter: blur(14px) saturate(160%);
  border-bottom: 1px solid transparent;
  transition: border-color 0.25s ease, background 0.25s ease;
}

.nav.is-stuck {
  border-bottom-color: var(--line);
  background: rgba(7, 9, 13, 0.92);
}

.nav__inner {
  display: flex;
  align-items: center;
  gap: 24px;
  min-height: 68px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 11px;
  margin-right: auto;
}

.brand__mark {
  flex: none;
  width: 34px;
  height: 34px;
  display: grid;
  place-items: center;
  border-radius: 10px;
  border: 1px solid var(--accent-line);
  background: var(--accent-soft);
  color: var(--accent);
  font-size: 17px;
  font-weight: 700;
}

.brand__text {
  display: flex;
  flex-direction: column;
  line-height: 1.25;
}

.brand__text strong {
  font-size: 15px;
  letter-spacing: 0.01em;
}

.brand__text em {
  font-style: normal;
  font-size: 10.5px;
  color: var(--text-3);
  text-transform: uppercase;
}

.nav__links {
  display: flex;
  align-items: center;
  gap: 4px;
}

.nav__links a {
  position: relative;
  padding: 8px 12px;
  border-radius: var(--r-s);
  font-size: 14px;
  color: var(--text-2);
  transition: color 0.16s ease, background 0.16s ease;
}

.nav__links a:hover {
  color: var(--text);
  background: rgba(255, 255, 255, 0.045);
}

.nav__actions {
  display: flex;
  align-items: center;
  gap: 10px;
}

.burger {
  display: none;
  width: 40px;
  height: 40px;
  padding: 0;
  border: 1px solid var(--line-2);
  border-radius: 10px;
  background: transparent;
  cursor: pointer;
}

.burger span {
  display: block;
  width: 16px;
  height: 1.5px;
  margin: 4px auto;
  background: var(--text);
  transition: transform 0.2s var(--ease), opacity 0.2s ease;
}

.burger[aria-expanded="true"] span:first-child {
  transform: translateY(2.75px) rotate(45deg);
}

.burger[aria-expanded="true"] span:last-child {
  transform: translateY(-2.75px) rotate(-45deg);
}

.nav__mobile {
  display: none;
  flex-direction: column;
  gap: 2px;
  padding: 10px var(--pad) 20px;
  border-top: 1px solid var(--line);
  background: var(--bg-2);
}

.nav__mobile a {
  padding: 12px 4px;
  border-bottom: 1px solid var(--line);
  color: var(--text-2);
}

.nav__mobile .btn {
  margin-top: 14px;
  justify-content: center;
}

/* -------------------------------------------------------------------- 按钮 */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 20px;
  border: 1px solid transparent;
  border-radius: 10px;
  font-size: 14.5px;
  font-weight: 600;
  cursor: pointer;
  white-space: nowrap;
  transition: transform 0.16s var(--ease), background 0.16s ease,
    border-color 0.16s ease, color 0.16s ease;
}

.btn--sm {
  padding: 9px 15px;
  font-size: 13.5px;
}

.btn--primary {
  background: var(--accent);
  color: var(--accent-ink);
  font-weight: 700;
}

.btn--primary:hover {
  background: var(--accent-hi);
  transform: translateY(-1px);
}

.btn--ghost {
  border-color: var(--line-2);
  background: rgba(255, 255, 255, 0.02);
  color: var(--text);
}

.btn--ghost:hover {
  border-color: var(--accent-line);
  background: var(--accent-soft);
  color: var(--accent-hi);
}

/* ------------------------------------------------------------------- 英雄区 */
.hero {
  position: relative;
  padding: clamp(48px, 7vw, 88px) 0 clamp(64px, 9vw, 116px);
  overflow: hidden;
}

.hero__bg {
  position: absolute;
  inset: 0;
  pointer-events: none;
  background-image: linear-gradient(var(--line) 1px, transparent 1px),
    linear-gradient(90deg, var(--line) 1px, transparent 1px);
  background-size: 68px 68px;
  -webkit-mask-image: radial-gradient(130% 78% at 62% 0%, #000 0%, transparent 72%);
  mask-image: radial-gradient(130% 78% at 62% 0%, #000 0%, transparent 72%);
  opacity: 0.75;
}

.hero__bg::after {
  content: "";
  position: absolute;
  inset: -20% -10% auto 25%;
  height: 520px;
  background: radial-gradient(closest-side, rgba(77, 141, 255, 0.22), transparent 100%);
}

.hero__inner {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1.02fr) minmax(0, 1.06fr);
  align-items: center;
  gap: clamp(36px, 5vw, 68px);
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  font-size: 12px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--text-3);
}

.eyebrow .dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--mint);
  box-shadow: 0 0 0 4px rgba(61, 220, 151, 0.14);
}

.hero__title {
  margin: 22px 0 20px;
  font-size: clamp(38px, 6.4vw, 66px);
  line-height: 1.1;
  letter-spacing: -0.02em;
  font-weight: 800;
}

.hero__title .hl {
  color: var(--accent);
  text-decoration: underline;
  text-decoration-color: var(--accent-line);
  text-decoration-thickness: 4px;
  text-underline-offset: 10px;
}

.hero__lede {
  max-width: 34em;
  color: var(--text-2);
  font-size: clamp(15px, 1.5vw, 17px);
}

.hero__cta {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 30px;
}

.facts {
  display: flex;
  flex-wrap: wrap;
  gap: clamp(20px, 4vw, 44px);
  margin-top: 40px;
  padding-top: 26px;
  border-top: 1px solid var(--line);
}

.fact dt {
  font-size: 22px;
  font-weight: 700;
  color: var(--text);
}

.fact dd {
  font-size: 12.5px;
  color: var(--text-3);
}

/* --------------------------------------------------------------- 浏览器 Mock */
.hero__visual {
  position: relative;
}

.mock {
  position: relative;
  border: 1px solid var(--line-2);
  border-radius: var(--r-l);
  background: var(--surface);
  box-shadow: var(--shadow-l);
  overflow: hidden;
}

.browser__bar {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 11px 14px;
  background: var(--surface-2);
  border-bottom: 1px solid var(--line);
}

.browser__dots {
  display: flex;
  gap: 6px;
}

.browser__dots i {
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--surface-3);
  border: 1px solid var(--line-2);
}

.browser__url {
  flex: 1;
  min-width: 0;
  overflow: hidden;
  white-space: nowrap;
  text-overflow: ellipsis;
  padding: 5px 11px;
  border-radius: 6px;
  background: rgba(0, 0, 0, 0.4);
  font-size: 11px;
  color: var(--text-3);
}

.browser__ext {
  display: grid;
  place-items: center;
  width: 22px;
  height: 22px;
  border-radius: 6px;
  background: var(--accent-soft);
  border: 1px solid var(--accent-line);
  color: var(--accent);
  font-size: 11px;
  font-weight: 700;
}

.browser__body {
  padding: 18px 20px 58px;
}

.doc__meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  font-size: 10px;
  letter-spacing: 0.1em;
  color: var(--text-3);
}

.chip {
  padding: 3px 9px;
  border-radius: 999px;
  border: 1px solid var(--line-2);
  color: var(--text-2);
  letter-spacing: 0.04em;
  transition: color 0.3s ease, border-color 0.3s ease, background 0.3s ease;
}

.chip.is-done {
  color: var(--mint);
  border-color: rgba(61, 220, 151, 0.4);
  background: rgba(61, 220, 151, 0.1);
}

.doc__title {
  margin: 14px 0 12px;
  font-size: 18px;
  line-height: 1.35;
  font-weight: 700;
}

.doc__p {
  margin-bottom: 12px;
  font-size: 13.5px;
  line-height: 1.75;
  color: var(--text-2);
}

.doc__list {
  margin: 4px 0 14px;
  display: grid;
  gap: 7px;
}

.doc__list li {
  position: relative;
  padding-left: 16px;
  font-size: 13px;
  color: var(--text-2);
}

.doc__list li::before {
  content: "";
  position: absolute;
  left: 2px;
  top: 9px;
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--accent-line);
}

.doc__lines {
  display: grid;
  gap: 8px;
}

.doc__lines i,
.bar {
  display: block;
  height: 9px;
  border-radius: 5px;
  background: linear-gradient(90deg, var(--surface-3) 25%, #232a35 50%, var(--surface-3) 75%);
  background-size: 300% 100%;
}

.swap,
.bar.swap2 {
  transition: opacity 0.26s ease, background-color 0.5s ease;
}

.swap.is-swapping,
.bar.is-swapping {
  opacity: 0.12;
}

.swap.is-flash,
.bar.is-flash {
  background-color: var(--accent-soft);
}

.doc__lines i:nth-child(1) { width: 82%; }
.doc__lines i:nth-child(2) { width: 66%; }
.doc__lines i:nth-child(3) { width: 74%; }

/* 悬浮球 */
.fab {
  position: absolute;
  right: 18px;
  bottom: 18px;
  display: flex;
  flex-direction: column;
  align-items: flex-end;
  gap: 10px;
}

.fab__menu {
  display: flex;
  flex-direction: column;
  gap: 2px;
  padding: 6px;
  min-width: 148px;
  border: 1px solid var(--line-2);
  border-radius: var(--r-m);
  background: var(--surface-2);
  box-shadow: var(--shadow-m);
  opacity: 0;
  transform: translateY(8px) scale(0.97);
  transform-origin: bottom right;
  transition: opacity 0.2s ease, transform 0.2s var(--ease);
}

.fab.is-open .fab__menu {
  opacity: 1;
  transform: none;
}

.fab__item {
  display: flex;
  align-items: center;
  gap: 9px;
  padding: 6px 10px;
  border-radius: 8px;
  font-size: 12.5px;
  color: var(--text-2);
}

.fab__item i {
  font-style: normal;
  font-size: 12px;
  width: 16px;
  text-align: center;
}

.fab__item:first-child {
  background: var(--accent-soft);
  color: var(--accent-hi);
}

.fab__btn {
  display: grid;
  place-items: center;
  width: 46px;
  height: 46px;
  border-radius: 50%;
  background: var(--accent);
  color: var(--accent-ink);
  font-size: 17px;
  font-weight: 700;
  box-shadow: 0 12px 26px -10px rgba(77, 141, 255, 0.7);
}

.mock__replay {
  position: absolute;
  left: 18px;
  bottom: 18px;
  padding: 6px 12px;
  border: 1px solid var(--line-2);
  border-radius: 999px;
  background: rgba(7, 9, 13, 0.7);
  font-size: 11px;
  color: var(--text-3);
  cursor: pointer;
  transition: color 0.16s ease, border-color 0.16s ease;
}

.mock__replay:hover {
  color: var(--accent-hi);
  border-color: var(--accent-line);
}

/* --------------------------------------------------------------- 通用区块 */
.section {
  position: relative;
  padding: var(--sec-y) 0;
  scroll-margin-top: 84px;
}

.section--alt {
  background: var(--bg-2);
  border-block: 1px solid var(--line);
}

.head {
  max-width: 720px;
  margin-bottom: clamp(36px, 5vw, 60px);
}

.head__title {
  margin: 16px 0 14px;
  font-size: clamp(27px, 3.6vw, 42px);
  line-height: 1.18;
  letter-spacing: -0.018em;
  font-weight: 800;
}

.head__lede {
  color: var(--text-2);
  font-size: clamp(14.5px, 1.4vw, 16.5px);
}

/* ------------------------------------------------------- 核心功能：三栏切换 */
.showcase {
  display: grid;
  grid-template-columns: minmax(0, 340px) minmax(0, 1fr);
  gap: clamp(20px, 3vw, 34px);
  align-items: start;
}

.tabs {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.tab {
  display: flex;
  align-items: center;
  gap: 14px;
  width: 100%;
  padding: 16px 16px 16px 18px;
  text-align: left;
  border: 1px solid var(--line);
  border-radius: var(--r-m);
  background: rgba(255, 255, 255, 0.015);
  cursor: pointer;
  transition: border-color 0.18s ease, background 0.18s ease,
    transform 0.18s var(--ease);
}

.tab:hover {
  border-color: var(--line-2);
  background: rgba(255, 255, 255, 0.035);
}

.tab.is-active {
  border-color: var(--accent-line);
  background: var(--accent-soft);
}

.tab__num {
  font-size: 12px;
  color: var(--text-3);
  transition: color 0.18s ease;
}

.tab.is-active .tab__num {
  color: var(--accent);
}

.tab__body {
  display: flex;
  flex-direction: column;
  gap: 3px;
  min-width: 0;
}

.tab__body strong {
  font-size: 15.5px;
  font-weight: 700;
}

.tab__body small {
  font-size: 12.5px;
  color: var(--text-3);
}

.tab__mark {
  margin-left: auto;
  color: var(--text-3);
  opacity: 0;
  transform: translateX(-4px);
  transition: opacity 0.18s ease, transform 0.18s var(--ease);
}

.tab.is-active .tab__mark {
  opacity: 1;
  transform: none;
  color: var(--accent);
}

.panel {
  display: grid;
  gap: 26px;
  padding: clamp(18px, 2.6vw, 26px);
  border: 1px solid var(--line);
  border-radius: var(--r-l);
  background: var(--surface);
  box-shadow: var(--shadow-m);
}

.panel[hidden] {
  display: none;
}

.panel__info h3 {
  font-size: 19px;
  font-weight: 700;
  letter-spacing: -0.01em;
}

.points {
  display: grid;
  gap: 10px;
  margin-top: 16px;
}

.points li {
  position: relative;
  padding-left: 24px;
  font-size: 14.5px;
  color: var(--text-2);
}

.points li::before {
  content: "";
  position: absolute;
  left: 3px;
  top: 10px;
  width: 9px;
  height: 5px;
  border-left: 1.6px solid var(--mint);
  border-bottom: 1.6px solid var(--mint);
  transform: rotate(-45deg);
}

.points code {
  padding: 1px 6px;
  border-radius: 5px;
  background: var(--surface-3);
  color: var(--text);
}

.kbd-row {
  display: flex;
  align-items: center;
  gap: 6px;
  margin-top: 20px;
  padding-top: 16px;
  border-top: 1px solid var(--line);
}

.kbd-label {
  margin-right: 4px;
  font-size: 12.5px;
  color: var(--text-3);
}

kbd {
  padding: 3px 8px;
  border: 1px solid var(--line-2);
  border-bottom-width: 2px;
  border-radius: 6px;
  background: var(--surface-2);
  font-family: var(--mono);
  font-size: 11.5px;
  color: var(--text-2);
}

/* 面板内的可视化演示 */
.mini {
  position: relative;
  border: 1px solid var(--line);
  border-radius: var(--r-m);
  background: var(--bg-2);
  overflow: hidden;
}

.mini__bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 9px 14px;
  border-bottom: 1px solid var(--line);
  background: var(--surface-2);
  font-size: 10.5px;
  letter-spacing: 0.08em;
  color: var(--text-3);
}

.mini__bar b {
  color: var(--accent);
  font-weight: 600;
  letter-spacing: 0.04em;
}

.mini__body {
  display: grid;
  gap: 12px;
  padding: 20px;
}

.bar.w60 { width: 60%; }
.bar.w70 { width: 70%; }
.bar.w75 { width: 75%; }
.bar.w80 { width: 80%; }
.bar.w88 { width: 88%; }
.bar.w90 { width: 90%; }
.bar.w92 { width: 92%; }
.bar.w95 { width: 95%; }

.bar.swap2 {
  height: auto;
  min-height: 0;
  padding: 0;
  border-radius: 0;
  background: none;
  font-size: 13px;
  line-height: 1.7;
  color: var(--text-2);
}

/* 划词面板 */
.mini--ink {
  padding: 22px 20px 96px;
}

.read p {
  margin-bottom: 14px;
  font-size: 14px;
  line-height: 1.8;
  color: var(--text-2);
}

.read mark {
  padding: 2px 3px;
  border-radius: 4px;
  background: rgba(77, 141, 255, 0.2);
  color: var(--text);
  box-shadow: inset 0 -1px 0 var(--accent-line);
}

.read__dim {
  color: var(--text-3) !important;
}

.selcard {
  position: absolute;
  left: 46%;
  bottom: 18px;
  width: min(300px, 78%);
  border: 1px solid var(--line-2);
  border-radius: var(--r-m);
  background: var(--surface-2);
  box-shadow: var(--shadow-m);
  overflow: hidden;
}

.selcard__head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 7px 12px;
  border-bottom: 1px solid var(--line);
  background: var(--accent-soft);
  font-size: 10.5px;
  letter-spacing: 0.08em;
  color: var(--accent);
}

.selcard__head span {
  padding: 2px 7px;
  border-radius: 5px;
  background: rgba(255, 255, 255, 0.06);
  color: var(--text-3);
}

.selcard__src {
  padding: 10px 12px 0;
  font-size: 12px;
  color: var(--text-3);
}

.selcard__dst {
  padding: 4px 12px 12px;
  font-size: 14px;
  font-weight: 600;
}

/* 总结面板 */
.mini--split {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1.05fr);
  gap: 18px;
  padding: 20px;
  align-items: start;
}

.read--faded {
  display: grid;
  gap: 12px;
  opacity: 0.45;
}

.sum {
  border: 1px solid var(--line-2);
  border-radius: var(--r-m);
  background: var(--surface-2);
  overflow: hidden;
}

.sum__head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 8px 12px;
  border-bottom: 1px solid var(--line);
  background: var(--accent-soft);
  font-size: 10.5px;
  letter-spacing: 0.08em;
  color: var(--accent);
}

.sum__head span {
  color: var(--text-3);
}

.sum__body {
  min-height: 210px;
  padding: 12px 14px;
  font-size: 13px;
  line-height: 1.75;
  color: var(--text-2);
}

.sum__body h4 {
  margin: 0 0 8px;
  padding-left: 8px;
  border-left: 3px solid var(--accent);
  font-size: 12.5px;
  color: var(--text);
}

.sum__body li {
  position: relative;
  margin-bottom: 6px;
  padding-left: 15px;
}

.sum__body li::before {
  content: "";
  position: absolute;
  left: 3px;
  top: 9px;
  width: 4px;
  height: 4px;
  border-radius: 50%;
  background: var(--accent-line);
}

.sum__caret {
  display: inline-block;
  width: 7px;
  height: 14px;
  vertical-align: -2px;
  background: var(--accent);
  animation: caret 1s steps(2, jump-none) infinite;
}

@keyframes caret {
  0%, 100% { opacity: 1; }
  50% { opacity: 0; }
}

/* ------------------------------------------------------------ 更多能力网格 */
.grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 14px;
}

.card {
  padding: 24px 22px;
  border: 1px solid var(--line);
  border-radius: var(--r-l);
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.035), rgba(255, 255, 255, 0) 62%);
  transition: border-color 0.2s ease, transform 0.2s var(--ease);
}

.card:hover {
  border-color: var(--line-2);
  transform: translateY(-3px);
}

.card__icon {
  display: grid;
  place-items: center;
  width: 38px;
  height: 38px;
  margin-bottom: 16px;
  border-radius: 10px;
  border: 1px solid var(--line-2);
  background: var(--surface-2);
  font-size: 16px;
  color: var(--accent);
}

.card h3 {
  margin-bottom: 8px;
  font-size: 16px;
  font-weight: 700;
}

.card p {
  font-size: 14px;
  color: var(--text-2);
}

/* ------------------------------------------------------------ 安装步骤 */
.install {
  display: grid;
  grid-template-columns: minmax(0, 1.55fr) minmax(0, 1fr);
  gap: clamp(20px, 3vw, 36px);
  align-items: start;
}

.steps {
  counter-reset: step;
}

.step {
  display: flex;
  gap: 18px;
  padding: 22px 0;
  border-top: 1px solid var(--line);
}

.step:last-child {
  border-bottom: 1px solid var(--line);
}

.step__num {
  flex: none;
  padding-top: 2px;
  font-size: 13px;
  color: var(--accent);
}

.step__body h3 {
  font-size: 16.5px;
  font-weight: 700;
}

.step__body p {
  margin-top: 7px;
  font-size: 14px;
  color: var(--text-2);
}

.copyline {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  margin-top: 12px;
}

.copyline code {
  padding: 7px 12px;
  border: 1px solid var(--line);
  border-radius: var(--r-s);
  background: var(--surface-2);
  font-size: 12.5px;
  color: var(--text);
}

.copy {
  padding: 6px 13px;
  border: 1px solid var(--line-2);
  border-radius: var(--r-s);
  background: transparent;
  font-size: 12.5px;
  color: var(--text-2);
  cursor: pointer;
  transition: color 0.16s ease, border-color 0.16s ease, background 0.16s ease;
}

.copy:hover {
  color: var(--accent-hi);
  border-color: var(--accent-line);
  background: var(--accent-soft);
}

.copy.is-done {
  color: var(--mint);
  border-color: rgba(61, 220, 151, 0.4);
}

.copyline__hint {
  font-size: 12px;
  color: var(--text-3);
}

.notice {
  position: sticky;
  top: 92px;
  padding: 22px;
  border: 1px solid var(--line);
  border-radius: var(--r-l);
  background: var(--surface);
}

.notice h3 {
  margin-bottom: 14px;
  font-size: 11px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--text-3);
}

.notice li {
  position: relative;
  margin-bottom: 11px;
  padding-left: 16px;
  font-size: 13.5px;
  color: var(--text-2);
}

.notice li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 10px;
  width: 6px;
  height: 1px;
  background: var(--amber);
}

.notice code,
.notice .mono {
  color: var(--text);
}

/* ------------------------------------------------------------ 兼容服务 */
.compat {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1.25fr);
  gap: clamp(20px, 3vw, 36px);
  align-items: start;
}

.chips {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.chip2 {
  padding: 9px 15px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--surface);
  font-size: 13.5px;
  color: var(--text-2);
  transition: border-color 0.18s ease, color 0.18s ease;
}

.chip2:hover {
  border-color: var(--accent-line);
  color: var(--text);
}

.code {
  border: 1px solid var(--line-2);
  border-radius: var(--r-l);
  background: var(--surface);
  overflow: hidden;
  box-shadow: var(--shadow-m);
}

.code__head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 14px;
  border-bottom: 1px solid var(--line);
  background: var(--surface-2);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--text-3);
}

.code__dots {
  display: flex;
  gap: 5px;
}

.code__dots i {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--surface-3);
  border: 1px solid var(--line-2);
}

.code pre {
  margin: 0;
  padding: 18px;
  overflow-x: auto;
  font-size: 12.5px;
  line-height: 1.85;
  color: var(--text-2);
}

.c-k { color: var(--accent); }
.c-s { color: #9fd2ff; }
.c-v { color: var(--mint); }
.c-c { color: var(--text-3); }

/* ------------------------------------------------------------ FAQ */
.faq {
  display: grid;
  gap: 10px;
}

.qa {
  border: 1px solid var(--line);
  border-radius: var(--r-m);
  background: var(--surface);
  overflow: hidden;
  transition: border-color 0.2s ease;
}

.qa[open] {
  border-color: var(--line-2);
}

.qa summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 18px 20px;
  font-size: 15.5px;
  font-weight: 600;
  cursor: pointer;
  list-style: none;
}

.qa summary::-webkit-details-marker {
  display: none;
}

.qa__icon {
  position: relative;
  flex: none;
  width: 14px;
  height: 14px;
}

.qa__icon::before,
.qa__icon::after {
  content: "";
  position: absolute;
  inset: 50% 0 auto 0;
  height: 1.5px;
  background: var(--text-3);
  transition: transform 0.22s var(--ease), background 0.2s ease;
}

.qa__icon::after {
  transform: rotate(90deg);
}

.qa[open] .qa__icon::after {
  transform: rotate(0);
  background: var(--accent);
}

.qa[open] .qa__icon::before {
  background: var(--accent);
}

.qa__body {
  padding: 0 20px 20px;
}

.qa__body p {
  font-size: 14px;
  color: var(--text-2);
}

/* ------------------------------------------------------------ 隐私说明带 */
.band {
  border-block: 1px solid var(--line);
  background: var(--bg-2);
  padding: clamp(34px, 5vw, 54px) 0;
}

.band__inner {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: clamp(20px, 4vw, 48px);
}

.band__item span {
  font-size: 11px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--accent);
}

.band__item p {
  margin-top: 8px;
  font-size: 14px;
  color: var(--text-2);
}

/* ------------------------------------------------------------ 页脚 */
.footer {
  padding: clamp(40px, 5vw, 64px) 0 34px;
}

.footer__top {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 28px;
  padding-bottom: 28px;
  border-bottom: 1px solid var(--line);
}

.footer__brand {
  display: flex;
  align-items: center;
  gap: 12px;
}

.footer__brand strong {
  font-size: 15px;
}

.footer__brand p {
  font-size: 13px;
  color: var(--text-3);
}

.footer__nav {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 22px;
  align-items: center;
  font-size: 14px;
  color: var(--text-2);
}

.footer__nav a:hover {
  color: var(--accent-hi);
}

.footer__bottom {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 10px;
  padding-top: 22px;
  font-size: 11.5px;
  color: var(--text-3);
}

/* ------------------------------------------------------------ 滚动入场动效 */
.js [data-reveal] {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity 0.7s var(--ease), transform 0.7s var(--ease);
}

.js [data-reveal][data-delay="1"] { transition-delay: 0.08s; }
.js [data-reveal][data-delay="2"] { transition-delay: 0.16s; }
.js [data-reveal][data-delay="3"] { transition-delay: 0.24s; }

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

/* ------------------------------------------------------------ 响应式断点 */
@media (max-width: 1100px) {
  .hero__inner {
    grid-template-columns: minmax(0, 1fr);
    gap: 44px;
  }

  .hero__visual {
    max-width: 700px;
  }

  .hero__title .hl {
    text-decoration-thickness: 3px;
    text-underline-offset: 7px;
  }
}

@media (max-width: 1024px) {
  .showcase,
  .install,
  .compat {
    grid-template-columns: minmax(0, 1fr);
  }

  .tabs {
    flex-direction: row;
    overflow-x: auto;
    padding-bottom: 4px;
    scrollbar-width: none;
  }

  .tabs::-webkit-scrollbar {
    display: none;
  }

  .tab {
    flex: 0 0 auto;
    padding: 12px 15px;
  }

  .tab__body small,
  .tab__mark {
    display: none;
  }

  .tab__body strong {
    font-size: 14.5px;
    white-space: nowrap;
  }

  .grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .notice {
    position: static;
  }

  .band__inner {
    grid-template-columns: minmax(0, 1fr);
    gap: 22px;
  }
}

@media (max-width: 860px) {
  .nav__links {
    display: none;
  }

  .burger {
    display: block;
  }

  .nav__mobile:not([hidden]) {
    display: flex;
  }

  .nav__actions .btn {
    display: none;
  }
}

@media (max-width: 620px) {
  body {
    font-size: 15.5px;
  }

  .grid {
    grid-template-columns: minmax(0, 1fr);
  }

  .facts {
    gap: 20px 28px;
  }

  .fact dt {
    font-size: 19px;
  }

  .mini--split {
    grid-template-columns: minmax(0, 1fr);
  }

  .mini--ink {
    padding-bottom: 20px;
  }

  .selcard {
    position: static;
    width: 100%;
    margin-top: 16px;
  }

  .step {
    flex-direction: column;
    gap: 8px;
  }

  .code pre {
    font-size: 11.5px;
  }

  .footer__top {
    flex-direction: column;
  }
}

/* ------------------------------------------------------------ 减弱动效 */
@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

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

  .sum__caret {
    animation: none;
  }

  .btn,
  .card,
  .tab,
  .swap,
  .bar.swap2 {
    transition: none;
  }
}