/* 学见官网 · 基础与布局 */

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

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

body {
  margin: 0;
  background: var(--ink-1000);
  color: var(--paper);
  font-family: var(--font-body);
  font-size: var(--fs-body);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
}

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

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

img, svg, canvas {
  display: block;
  max-width: 100%;
}

::selection {
  background: var(--cinnabar);
  color: #fff;
}

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

/* 跳到主要内容 */
.skip-link {
  position: absolute;
  left: 16px;
  top: -80px;
  z-index: 100;
  padding: 12px 20px;
  background: var(--cinnabar);
  color: #fff;
  border-radius: var(--radius-pill);
  font-size: var(--fs-small);
  transition: top var(--dur-state) var(--ease-out);
}

.skip-link:focus {
  top: 16px;
}

/* 全局底纹：深墨渐变（单层，无平铺，无噪点） */
.page-bg {
  position: fixed;
  inset: 0;
  z-index: -2;
  background:
    radial-gradient(1100px 700px at 18% -10%, rgba(201, 56, 42, 0.13), transparent 62%),
    radial-gradient(900px 620px at 88% 8%, rgba(46, 125, 107, 0.09), transparent 65%),
    radial-gradient(1200px 900px at 50% 120%, rgba(201, 56, 42, 0.07), transparent 70%),
    radial-gradient(60% 45% at 50% 0%, rgba(255, 255, 255, 0.03), transparent 70%),
    var(--ink-1000);
  background-repeat: no-repeat;
  background-size: cover;
}

/* 顶部进度线 */
.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  height: 2px;
  width: 100%;
  transform: scaleX(0);
  transform-origin: 0 50%;
  background: linear-gradient(90deg, var(--cinnabar), var(--cinnabar-bright));
  z-index: 60;
  pointer-events: none;
}

/* 容器 */
.container {
  width: min(100% - 48px, var(--container));
  margin-inline: auto;
}

.section {
  position: relative;
  padding-block: var(--section-y);
}

.section--tight {
  padding-block: clamp(64px, 8vw, 112px);
}

/* 区块标题 */
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: var(--fs-tiny);
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--paper-45);
}

.eyebrow::before {
  content: "";
  width: 24px;
  height: 1px;
  background: var(--cinnabar);
}

.section-title {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: var(--fs-h2);
  line-height: 1.18;
  letter-spacing: -0.02em;
  margin-top: var(--gap-md);
  max-width: 20ch;
  text-wrap: balance;
}

.section-lead {
  margin-top: var(--gap-sm);
  max-width: 52ch;
  color: var(--paper-70);
  font-size: var(--fs-lead);
}

/* 导航 */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 50;
  padding: 18px 0;
  transition: background var(--dur-layout) var(--ease-out),
    backdrop-filter var(--dur-layout) var(--ease-out),
    border-color var(--dur-layout) var(--ease-out);
  border-bottom: 1px solid transparent;
}

.nav.is-scrolled {
  background: rgba(7, 7, 10, 0.72);
  backdrop-filter: blur(18px) saturate(140%);
  border-bottom-color: var(--line);
}

.nav__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--gap-md);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  font-family: var(--font-display);
  font-size: 20px;
  letter-spacing: 0.08em;
}

.brand__mark {
  width: 34px;
  height: 34px;
  border-radius: 9px;
  display: grid;
  place-items: center;
  background: linear-gradient(155deg, var(--cinnabar-bright), #93251b);
  box-shadow: 0 6px 24px rgba(201, 56, 42, 0.32);
  font-size: 17px;
  color: #fff;
}

.nav__links {
  display: flex;
  align-items: center;
  gap: 28px;
  font-size: var(--fs-small);
  color: var(--paper-70);
}

.nav__links a {
  position: relative;
  transition: color var(--dur-state) var(--ease-out);
}

.nav__links a::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -6px;
  width: 100%;
  height: 1px;
  background: var(--cinnabar);
  transform: scaleX(0);
  transform-origin: 0 50%;
  transition: transform var(--dur-state) var(--ease-out);
}

.nav__links a:hover {
  color: var(--paper);
}

.nav__links a:hover::after {
  transform: scaleX(1);
}

/* 按钮 */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  height: 48px;
  padding: 0 26px;
  border-radius: var(--radius-pill);
  border: 1px solid transparent;
  font-family: var(--font-body);
  font-size: 15px;
  font-weight: 500;
  cursor: pointer;
  transition: transform var(--dur-micro) var(--ease-out),
    box-shadow var(--dur-state) var(--ease-out),
    background var(--dur-state) var(--ease-out),
    border-color var(--dur-state) var(--ease-out);
}

.btn--primary {
  background: linear-gradient(150deg, var(--cinnabar-bright), #a92a1e);
  color: #fff;
  box-shadow: 0 10px 34px rgba(201, 56, 42, 0.3);
}

.btn--primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 16px 44px rgba(201, 56, 42, 0.42);
}

.btn--primary:active {
  transform: translateY(0) scale(0.985);
}

.btn--ghost {
  background: rgba(243, 239, 230, 0.04);
  border-color: var(--line-strong);
  color: var(--paper);
}

.btn--ghost:hover {
  background: rgba(243, 239, 230, 0.08);
  border-color: rgba(243, 239, 230, 0.26);
  transform: translateY(-2px);
}

.btn--disabled {
  background: rgba(243, 239, 230, 0.06);
  border-color: var(--line);
  color: var(--paper-45);
  cursor: not-allowed;
  box-shadow: none;
}

.btn--lg {
  height: 56px;
  padding: 0 34px;
  font-size: 16px;
}

/* 首屏 */
.hero {
  position: relative;
  min-height: 100svh;
  display: flex;
  align-items: center;
  padding-top: 120px;
  padding-bottom: 88px;
  overflow: hidden;
}

/* 全站粒子背景：固定铺满视口，整页任意位置都能被指针与陀螺仪扰动 */
.ink-bg {
  position: fixed;
  inset: 0;
  width: 100%;
  height: 100%;
  z-index: -1;
  pointer-events: none;
}

.hero__photo {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.85fr);
  align-items: center;
  gap: clamp(32px, 6vw, 88px);
}

.hero__badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 7px 14px;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius-pill);
  font-size: var(--fs-tiny);
  letter-spacing: 0.12em;
  color: var(--paper-70);
  background: rgba(7, 7, 10, 0.4);
}

.hero__badge i {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--jade);
  box-shadow: 0 0 10px var(--jade);
}

.hero__title {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--fs-display);
  line-height: 1;
  letter-spacing: 0.02em;
  margin-top: 26px;
  background: linear-gradient(180deg, #fffaf0 20%, #d8cfc1 92%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.hero__title .ch {
  display: inline-block;
  will-change: transform, opacity;
}

.hero__slogan {
  margin-top: 18px;
  font-family: var(--font-display);
  font-size: clamp(20px, 2.2vw, 28px);
  letter-spacing: 0.2em;
  color: var(--paper-70);
}

.hero__desc {
  margin-top: var(--gap-md);
  max-width: 34ch;
  font-size: var(--fs-lead);
  color: var(--paper-70);
}

.hero__actions {
  margin-top: var(--gap-lg);
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--gap-md);
}

.hero__meta {
  margin-top: var(--gap-md);
  font-family: var(--font-mono);
  font-size: var(--fs-tiny);
  letter-spacing: 0.14em;
  color: var(--paper-28);
}

.hero__hint {
  position: absolute;
  left: 50%;
  bottom: 26px;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.2em;
  color: var(--paper-28);
}

.hero__hint::after {
  content: "";
  width: 1px;
  height: 42px;
  background: linear-gradient(180deg, var(--paper-28), transparent);
}

/* 笔锋 */
.brush {
  width: 100%;
  height: auto;
  overflow: visible;
}

.brush path {
  fill: none;
  stroke-linecap: round;
}

/* 首屏右侧视觉 */
.hero__visual {
  position: relative;
  display: grid;
  place-items: center;
  min-height: min(560px, 62vh);
}

.hero__visual .brush {
  position: absolute;
  top: 4%;
  left: -14%;
  width: 128%;
  opacity: 0.92;
  pointer-events: none;
}

/* 手机模型 */
.phone {
  position: relative;
  justify-self: center;
  width: min(300px, 78%);
  aspect-ratio: 9 / 19.2;
  border-radius: 38px;
  border: 1px solid var(--line-strong);
  background: linear-gradient(165deg, #16161f, #0a0a0f 60%);
  box-shadow: 0 40px 90px rgba(0, 0, 0, 0.6), 0 0 0 8px rgba(255, 255, 255, 0.02) inset;
  padding: 12px;
  will-change: transform;
}

.phone__screen {
  position: relative;
  height: 100%;
  border-radius: 28px;
  overflow: hidden;
  background:
    radial-gradient(120% 90% at 50% 0%, rgba(201, 56, 42, 0.16), transparent 60%),
    var(--ink-950);
  display: flex;
  flex-direction: column;
  gap: 14px;
  padding: 26px 20px;
}

.phone__notch {
  position: absolute;
  top: 12px;
  left: 50%;
  transform: translateX(-50%);
  width: 84px;
  height: 20px;
  border-radius: 12px;
  background: #04040a;
  border: 1px solid rgba(255, 255, 255, 0.06);
}

.phone__head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 8px;
}

.phone__brand {
  font-family: var(--font-display);
  font-size: 17px;
  letter-spacing: 0.18em;
  color: var(--paper);
}

.phone__sub {
  font-family: var(--font-mono);
  font-size: 9px;
  letter-spacing: 0.08em;
  color: var(--paper-28);
}

.phone__modules {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 8px;
  margin-top: 4px;
}

.phone__module {
  position: relative;
  padding: 10px 11px;
  border-radius: 11px;
  border: 1px solid var(--line);
  background:
    radial-gradient(85% 70% at 20% 10%, rgba(243, 239, 230, 0.08), transparent 62%),
    var(--ink-900);
  min-height: 76px;
  display: flex;
  flex-direction: column;
  justify-content: center;
}

.phone__module-num {
  font-family: var(--font-mono);
  font-size: 8px;
  letter-spacing: 0.14em;
  color: var(--cinnabar);
}

.phone__module-glyph {
  font-family: var(--font-display);
  font-size: 19px;
  line-height: 1.2;
  color: rgba(243, 239, 230, 0.74);
}

.phone__module-name {
  font-size: 9px;
  letter-spacing: 0.04em;
  color: var(--paper-45);
  margin-top: 2px;
}

.phone__qrbar {
  margin-top: auto;
  display: flex;
  align-items: center;
  gap: 10px;
  padding-top: 11px;
  border-top: 1px solid var(--line);
}

.phone__qrbox {
  width: 40px;
  height: 40px;
  flex: none;
  border-radius: 6px;
  border: 1px dashed var(--line-strong);
  display: grid;
  place-items: center;
  font-family: var(--font-mono);
  font-size: 7px;
  line-height: 1.2;
  text-align: center;
  color: var(--paper-28);
  background: rgba(243, 239, 230, 0.03);
}

.phone__qrtip {
  font-size: 9px;
  line-height: 1.5;
  color: var(--paper-45);
}

.phone__qrtip strong {
  display: block;
  font-weight: 500;
  color: var(--paper-70);
  font-size: 10px;
}

/* 三支柱 */
.pillars {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1px;
  margin-top: clamp(48px, 6vw, 88px);
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  overflow: hidden;
}

.pillar {
  padding: clamp(28px, 3.4vw, 48px);
  /* 半透明，让底层墨点透出来 */
  background: rgba(11, 11, 16, 0.76);
  transition: background var(--dur-state) var(--ease-out);
}

.pillar:hover {
  background: rgba(18, 18, 26, 0.86);
}

.pillar__num {
  font-family: var(--font-display);
  font-size: 13px;
  letter-spacing: 0.3em;
  color: var(--cinnabar);
}

.pillar__title {
  margin-top: 18px;
  font-family: var(--font-display);
  font-size: var(--fs-h3);
  font-weight: 600;
}

.pillar__text {
  margin-top: 12px;
  color: var(--paper-70);
  font-size: 15px;
  max-width: 30ch;
}

/* 关于 */
.about__grid {
  display: grid;
  grid-template-columns: minmax(0, 0.9fr) minmax(0, 1.1fr);
  gap: clamp(32px, 5vw, 80px);
  align-items: start;
}

.about__body p {
  color: var(--paper-70);
  font-size: 16.5px;
  line-height: 1.95;
}

.about__body p + p {
  margin-top: 18px;
}

.about__body strong {
  color: var(--paper);
  font-weight: 500;
}

.about__facts {
  margin-top: 36px;
  display: grid;
  gap: 12px;
}

.about__fact {
  display: flex;
  align-items: baseline;
  gap: 14px;
  padding: 16px 18px;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: rgba(243, 239, 230, 0.02);
}

.about__fact b {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--cinnabar);
  flex: none;
}

.about__fact span {
  font-size: 14.5px;
  color: var(--paper-70);
}

/* 适合谁 */
.personas {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
  margin-top: clamp(40px, 5vw, 64px);
}

.persona {
  padding: 28px 24px;
  border-radius: var(--radius-md);
  border: 1px solid var(--line);
  background: rgba(11, 11, 16, 0.76);
  transition: border-color var(--dur-state) var(--ease-out), transform var(--dur-state) var(--ease-out);
}

.persona:hover {
  border-color: rgba(201, 56, 42, 0.42);
  transform: translateY(-3px);
}

.persona__tag {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.18em;
  color: var(--paper-28);
}

.persona__title {
  margin-top: 14px;
  font-family: var(--font-display);
  font-size: 21px;
  font-weight: 600;
}

.persona__text {
  margin-top: 8px;
  font-size: 14.5px;
  color: var(--paper-70);
  line-height: 1.8;
}

/* FAQ */
.faq {
  margin-top: clamp(40px, 5vw, 64px);
  border-top: 1px solid var(--line);
}

.faq__item {
  border-bottom: 1px solid var(--line);
}

.faq__item summary {
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 22px 4px;
  font-size: 17px;
  color: var(--paper);
  transition: color var(--dur-state) var(--ease-out);
}

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

.faq__item summary::after {
  content: "+";
  font-family: var(--font-mono);
  font-size: 18px;
  color: var(--cinnabar);
  transition: transform var(--dur-state) var(--ease-out);
}

.faq__item[open] summary::after {
  transform: rotate(45deg);
}

.faq__item summary:hover {
  color: #fff;
}

.faq__answer {
  padding: 0 4px 22px;
  color: var(--paper-70);
  font-size: 15px;
  line-height: 1.85;
  max-width: 72ch;
}

/* 功能：交错布局 */
.features {
  margin-top: clamp(48px, 6vw, 96px);
  display: flex;
  flex-direction: column;
  gap: clamp(56px, 7vw, 104px);
}

.feature {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  align-items: center;
  gap: clamp(32px, 5vw, 80px);
}

.feature:nth-child(even) .feature__visual {
  order: -1;
}

.feature__index {
  font-family: var(--font-mono);
  font-size: var(--fs-tiny);
  letter-spacing: 0.24em;
  color: var(--cinnabar);
}

.feature__title {
  margin-top: 14px;
  font-family: var(--font-display);
  font-size: var(--fs-h3);
  font-weight: 600;
  letter-spacing: -0.01em;
}

.feature__text {
  margin-top: 12px;
  max-width: 38ch;
  color: var(--paper-70);
  font-size: 15px;
}

.feature__visual {
  position: relative;
  aspect-ratio: 4 / 3;
  border-radius: var(--radius-lg);
  border: 1px solid var(--line);
  background:
    radial-gradient(85% 75% at 25% 20%, rgba(201, 56, 42, 0.14), transparent 62%),
    radial-gradient(70% 60% at 80% 85%, rgba(46, 125, 107, 0.1), transparent 60%),
    rgba(11, 11, 16, 0.68);
  overflow: hidden;
  display: grid;
  place-items: center;
}

.feature__visual::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, rgba(255, 255, 255, 0.045), transparent 45%);
  pointer-events: none;
}

.feature__glyph {
  font-family: var(--font-display);
  font-size: clamp(64px, 8vw, 108px);
  color: rgba(243, 239, 230, 0.16);
  transition: transform var(--dur-enter) var(--ease-out), color var(--dur-enter) var(--ease-out);
}

.feature:hover .feature__glyph {
  transform: scale(1.06);
  color: rgba(243, 239, 230, 0.26);
}

/* 下载区 */
.download {
  position: relative;
  padding-block: clamp(96px, 12vw, 168px);
  overflow: hidden;
  border-top: 1px solid var(--line);
}

.download__inner {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: minmax(0, 1.1fr) auto;
  align-items: center;
  gap: clamp(32px, 6vw, 96px);
}

.download__title {
  font-family: var(--font-display);
  font-size: var(--fs-h1);
  font-weight: 600;
  letter-spacing: -0.02em;
  line-height: 1.12;
}

.download__text {
  margin-top: var(--gap-sm);
  color: var(--paper-70);
  max-width: 40ch;
}

.download__actions {
  margin-top: var(--gap-lg);
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--gap-sm);
}

.download__note {
  margin-top: 18px;
  font-family: var(--font-mono);
  font-size: var(--fs-tiny);
  letter-spacing: 0.12em;
  color: var(--paper-45);
}

.qr {
  width: clamp(180px, 20vw, 232px);
  aspect-ratio: 1;
  padding: 18px;
  border-radius: var(--radius-md);
  background: rgba(18, 18, 26, 0.78);
  border: 1px solid var(--line-strong);
  display: grid;
  place-items: center;
  gap: 10px;
  transition: border-color var(--dur-state) var(--ease-out), box-shadow var(--dur-state) var(--ease-out);
}

.qr:hover {
  border-color: rgba(201, 56, 42, 0.5);
  box-shadow: 0 0 0 1px rgba(201, 56, 42, 0.24), 0 0 48px rgba(201, 56, 42, 0.16);
}

/* 二维码占位：不再用 6px 平铺网格线（细密重复纹在滚动时会闪成横竖线） */
.qr__box {
  position: relative;
  width: 100%;
  aspect-ratio: 1;
  border-radius: 8px;
  background:
    radial-gradient(120% 120% at 50% 0%, rgba(243, 239, 230, 0.04), transparent 65%),
    var(--ink-950);
  border: 1px dashed var(--line-strong);
  display: grid;
  place-items: center;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--paper-28);
  text-align: center;
  padding: 12px;
}

.qr__box::before,
.qr__box::after {
  content: "";
  position: absolute;
  width: 18px;
  height: 18px;
  border: 2px solid rgba(243, 239, 230, 0.2);
  border-radius: 3px;
}

.qr__box::before {
  top: 10px;
  left: 10px;
  border-right: 0;
  border-bottom: 0;
}

.qr__box::after {
  right: 10px;
  bottom: 10px;
  border-left: 0;
  border-top: 0;
}

.qr__caption {
  font-size: var(--fs-tiny);
  color: var(--paper-45);
  letter-spacing: 0.08em;
}

/* 页脚 */
.footer {
  border-top: 1px solid var(--line);
  padding-block: clamp(48px, 6vw, 80px) 32px;
  background: rgba(11, 11, 16, 0.88);
}

.footer__grid {
  display: grid;
  grid-template-columns: 1.4fr repeat(2, minmax(0, 0.6fr));
  gap: var(--gap-lg);
}

.footer__brand {
  max-width: 34ch;
}

.footer__slogan {
  margin-top: 14px;
  font-family: var(--font-display);
  letter-spacing: 0.14em;
  color: var(--paper-70);
}

.footer__desc {
  margin-top: 14px;
  font-size: var(--fs-small);
  color: var(--paper-45);
  max-width: 32ch;
}

.footer__title {
  font-family: var(--font-mono);
  font-size: var(--fs-tiny);
  letter-spacing: 0.18em;
  color: var(--paper-28);
  text-transform: uppercase;
  margin-bottom: 16px;
}

.footer__list {
  list-style: none;
  padding: 0;
  display: grid;
  gap: 10px;
  font-size: var(--fs-small);
  color: var(--paper-70);
}

.footer__list a {
  transition: color var(--dur-state) var(--ease-out);
}

.footer__list a:hover {
  color: var(--paper);
}

.footer__bottom {
  margin-top: clamp(40px, 5vw, 64px);
  padding-top: 24px;
  border-top: 1px solid var(--line);
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 12px;
  font-size: var(--fs-tiny);
  color: var(--paper-28);
  font-family: var(--font-mono);
  letter-spacing: 0.06em;
}

/* 占位标记（后期替换素材时方便检索） */
.placeholder-tag {
  position: absolute;
  top: 14px;
  right: 14px;
  padding: 5px 10px;
  border-radius: var(--radius-pill);
  border: 1px solid var(--line-strong);
  background: rgba(7, 7, 10, 0.6);
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.12em;
  color: var(--paper-45);
  z-index: 2;
}

/* 文档页（隐私政策 / 用户协议） */
.doc {
  padding-top: 132px;
  padding-bottom: var(--section-y);
}

.doc__inner {
  max-width: 720px;
}

.doc__title {
  font-family: var(--font-display);
  font-size: var(--fs-h1);
  font-weight: 600;
  letter-spacing: -0.02em;
  line-height: 1.15;
}

.doc__meta {
  margin-top: 14px;
  font-family: var(--font-mono);
  font-size: var(--fs-tiny);
  letter-spacing: 0.1em;
  color: var(--paper-45);
}

.doc h2 {
  font-family: var(--font-display);
  font-size: 22px;
  font-weight: 600;
  margin-top: 44px;
  padding-top: 24px;
  border-top: 1px solid var(--line);
  color: var(--paper);
}

.doc h3 {
  font-size: 17px;
  font-weight: 600;
  margin-top: 26px;
}

.doc p,
.doc li {
  margin-top: 12px;
  color: var(--paper-70);
  font-size: 15.5px;
  line-height: 1.85;
}

.doc ul {
  padding-left: 20px;
}

.doc a {
  color: var(--cinnabar-bright);
  border-bottom: 1px solid rgba(226, 85, 63, 0.4);
}

.doc__back {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 36px;
  font-size: var(--fs-small);
  color: var(--paper-45);
  transition: color var(--dur-state) var(--ease-out);
}

.doc__back:hover {
  color: var(--paper);
}

/* 响应式 */
@media (max-width: 1024px) {
  .hero__photo {
    grid-template-columns: 1fr;
  }

  .hero__visual {
    display: none;
  }

  .hero {
    padding-top: 104px;
  }
}

@media (max-width: 860px) {
  .pillars {
    grid-template-columns: 1fr;
  }

  .about__grid {
    grid-template-columns: 1fr;
  }

  .personas {
    grid-template-columns: 1fr;
  }

  .feature {
    grid-template-columns: 1fr;
    gap: 28px;
  }

  .feature:nth-child(even) .feature__visual {
    order: 0;
  }

  .download__inner {
    grid-template-columns: 1fr;
  }

  .qr {
    width: 176px;
  }

  .footer__grid {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 560px) {
  .container {
    width: calc(100% - 36px);
  }

  .nav__links {
    display: none;
  }

  .hero {
    min-height: 92svh;
    padding-top: 96px;
  }

  .hero__title {
    letter-spacing: 0.01em;
  }

  .footer__grid {
    grid-template-columns: 1fr;
  }
}