/* =========================================================
   梦梦AI 官网 · 共享样式
   纯静态页面，零外部依赖，字体使用系统中文黑体。
   版面：中性纸底 + 一套松绿主色 + 发丝分隔线 + 大字标题。
   ========================================================= */

:root {
  --paper: #f2f4ef;
  --surface: #fbfcf8;
  --ink: #141a16;
  --ink-2: #414a43;
  --ink-3: #5e675f;
  --line: #dce0d6;
  --line-2: #c6ccbf;
  --brand: #12695a;
  --brand-ink: #0b4b40;
  --brand-tint: #e2ece6;
  --radius: 10px;
  --wrap: 1180px;
  --gutter: clamp(20px, 5vw, 40px);
  --font: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei",
    "Source Han Sans SC", "Noto Sans CJK SC", "Noto Sans SC", system-ui,
    -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

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

html {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: 88px;
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

::selection {
  background: var(--brand-tint);
  color: var(--brand-ink);
}

:focus-visible {
  outline: 2px solid var(--brand);
  outline-offset: 3px;
}

a {
  color: var(--brand-ink);
  text-underline-offset: 3px;
}

p {
  margin: 0 0 12px;
}

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

.skip {
  position: absolute;
  left: 12px;
  top: -64px;
  z-index: 100;
  padding: 10px 14px;
  border-radius: 6px;
  background: var(--ink);
  color: #f6faf6;
  font-size: 14px;
  text-decoration: none;
  transition: top 0.15s ease;
}

.skip:focus {
  top: 12px;
}

/* ---------- 页头 ---------- */

.site-head {
  position: sticky;
  top: 0;
  z-index: 30;
  background: var(--paper);
  border-bottom: 1px solid var(--line);
}

@supports (backdrop-filter: blur(6px)) {
  .site-head {
    background: color-mix(in srgb, var(--paper) 88%, transparent);
    backdrop-filter: blur(8px);
  }
}

.head-inner {
  display: flex;
  align-items: center;
  gap: clamp(16px, 2vw, 32px);
  height: 68px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  flex: none;
  font-size: 19px;
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--ink);
  text-decoration: none;
}

.brand svg {
  display: block;
  width: 22px;
  height: 22px;
  color: var(--brand);
}

.nav {
  display: flex;
  align-items: center;
  gap: clamp(14px, 2vw, 28px);
  margin-left: auto;
}

.nav a {
  position: relative;
  padding: 6px 0;
  font-size: 14px;
  color: var(--ink-2);
  text-decoration: none;
  white-space: nowrap;
}

.nav a::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 1px;
  background: currentColor;
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.18s ease;
}

.nav a:hover,
.nav a:focus-visible {
  color: var(--ink);
}

.nav a:hover::after,
.nav a:focus-visible::after,
.nav a[aria-current="page"]::after {
  transform: scaleX(1);
}

.head-tag {
  flex: none;
  padding: 6px 11px;
  border: 1px solid #cfe0d7;
  border-radius: 999px;
  background: var(--brand-tint);
  color: var(--brand-ink);
  font-size: 12px;
  line-height: 1;
  white-space: nowrap;
}

/* ---------- 首屏 ---------- */

.hero {
  display: grid;
  grid-template-columns: minmax(0, 1.04fr) minmax(0, 0.96fr);
  gap: clamp(32px, 4.5vw, 64px);
  align-items: start;
  padding-top: clamp(48px, 6.5vw, 88px);
  padding-bottom: clamp(40px, 5vw, 64px);
}

.hero-copy h1 {
  margin: 0 0 18px;
  font-size: clamp(58px, 8.6vw, 116px);
  font-weight: 700;
  line-height: 0.94;
  letter-spacing: -0.03em;
  color: var(--ink);
}

.hero-copy h1 .logo-ai {
  font-weight: 600;
  letter-spacing: -0.05em;
}

.platform-tag {
  display: inline-block;
  margin: 0 0 20px;
  padding: 6px 12px;
  border: 1px solid #cfe0d7;
  border-radius: 999px;
  background: var(--brand-tint);
  color: var(--brand-ink);
  font-size: 12.5px;
  line-height: 1.4;
}

.hero-lead {
  margin: 0 0 26px;
  max-width: 32em;
  font-size: clamp(16px, 1.3vw, 18px);
  line-height: 1.85;
  color: var(--ink-2);
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-bottom: 20px;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 46px;
  padding: 0 22px;
  border: 1px solid var(--brand);
  border-radius: 8px;
  background: var(--brand);
  color: #f6faf6;
  font-size: 15px;
  font-weight: 600;
  text-decoration: none;
  transition: background 0.15s ease, border-color 0.15s ease;
}

.btn:hover {
  background: var(--brand-ink);
  border-color: var(--brand-ink);
}

.btn-quiet {
  background: transparent;
  border-color: var(--line-2);
  color: var(--ink);
}

.btn-quiet:hover {
  background: var(--surface);
  border-color: var(--ink-3);
}

.hero-note {
  margin: 0;
  font-size: 13px;
  line-height: 1.75;
  color: var(--ink-3);
}

/* 处理示意：干声 → 翻唱 */

.session {
  padding: 18px 20px 22px;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: var(--surface);
  box-shadow: 0 18px 40px -34px rgba(20, 26, 22, 0.45);
}

.session-top {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--line);
  font-size: 12px;
  color: var(--ink-3);
}

.session-top b {
  font-weight: 600;
  color: var(--ink-2);
  letter-spacing: 0.02em;
}

.track {
  display: grid;
  grid-template-columns: 84px minmax(0, 1fr);
  gap: 14px;
  align-items: center;
  padding: 14px 0;
}

.track + .track {
  border-top: 1px solid var(--line);
}

.track-label {
  font-size: 13px;
  line-height: 1.5;
  color: var(--ink);
}

.track-label em {
  display: block;
  margin-top: 2px;
  font-style: normal;
  font-size: 11px;
  letter-spacing: 0.02em;
  white-space: nowrap;
  color: var(--ink-3);
}

.wave {
  display: block;
  width: 100%;
  height: 56px;
}

.wave--dry {
  color: #b9c2b6;
}

.wave--full {
  color: var(--brand);
}

.session-foot {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  margin-top: 12px;
  padding-top: 12px;
  border-top: 1px solid var(--line);
  font-size: 12px;
  color: var(--ink-3);
}

/* ---------- 首屏数据条 ---------- */

.facts {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  margin: 0;
  border-top: 1px solid var(--line);
}

.fact {
  margin: 0;
  padding: 20px 0;
}

.fact + .fact {
  border-left: 1px solid var(--line);
  padding-left: clamp(20px, 3vw, 40px);
}

.fact dt {
  margin-bottom: 6px;
  font-size: 12px;
  letter-spacing: 0.02em;
  color: var(--ink-3);
}

.fact dd {
  margin: 0;
  font-size: 15px;
  font-weight: 500;
  color: var(--ink);
}

/* ---------- 通用区块 ---------- */

.section {
  padding: clamp(52px, 7vw, 92px) 0;
  border-top: 1px solid var(--line);
}

.sec-head {
  display: grid;
  grid-template-columns: 96px minmax(0, 1fr);
  gap: 0 clamp(20px, 3vw, 36px);
  margin-bottom: clamp(26px, 3.5vw, 44px);
}

.sec-label {
  grid-row: 1 / span 3;
  margin: 10px 0 0;
  font-size: 12.5px;
  line-height: 1.7;
  letter-spacing: 0.02em;
  color: var(--ink-3);
}

.sec-head h2 {
  grid-column: 2;
  margin: 0 0 14px;
  max-width: 22em;
  font-size: clamp(26px, 3.1vw, 38px);
  font-weight: 600;
  line-height: 1.3;
  letter-spacing: -0.015em;
}

.sec-intro {
  grid-column: 2;
  margin: 0;
  max-width: 46em;
  font-size: 16px;
  line-height: 1.85;
  color: var(--ink-2);
}

/* ---------- 功能 ---------- */

.feature-list {
  border-top: 1px solid var(--line);
}

.feature {
  display: grid;
  grid-template-columns: minmax(150px, 0.72fr) minmax(0, 1.9fr);
  gap: 14px clamp(24px, 4vw, 56px);
  padding: clamp(22px, 2.6vw, 30px) 0;
  border-bottom: 1px solid var(--line);
}

.feature h3 {
  margin: 0;
  font-size: 18px;
  font-weight: 600;
  line-height: 1.55;
  letter-spacing: 0.01em;
}

.feature p {
  margin: 0;
  max-width: 62ch;
  font-size: 15.5px;
  line-height: 1.9;
  color: var(--ink-2);
}

.list-note {
  margin: 22px 0 0;
  max-width: 62ch;
  padding-left: 14px;
  border-left: 2px solid var(--brand-tint);
  font-size: 13.5px;
  line-height: 1.85;
  color: var(--ink-3);
}

/* ---------- 三步流程 ---------- */

.flow {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--line);
  list-style: none;
}

.flow li {
  padding: 24px clamp(18px, 2.4vw, 30px) 6px 0;
}

.flow li + li {
  border-left: 1px solid var(--line);
  padding-left: clamp(18px, 2.4vw, 30px);
}

.flow .step {
  display: block;
  margin-bottom: 12px;
  font-size: 12px;
  font-variant-numeric: tabular-nums;
  letter-spacing: 0.14em;
  color: var(--brand);
}

.flow h3 {
  margin: 0 0 8px;
  font-size: 18px;
  font-weight: 600;
  line-height: 1.5;
}

.flow p {
  margin: 0;
  font-size: 15px;
  line-height: 1.85;
  color: var(--ink-2);
}

.flow-note {
  margin: 26px 0 0;
  font-size: 13.5px;
  line-height: 1.85;
  color: var(--ink-3);
}

/* ---------- 价格 ---------- */

.plans {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  border-top: 1px solid var(--line-2);
  border-bottom: 1px solid var(--line-2);
}

.plan {
  display: flex;
  flex-direction: column;
  padding: 26px 0 28px;
}

.plan + .plan {
  border-left: 1px solid var(--line);
  padding-left: clamp(20px, 3vw, 36px);
}

.plan-name {
  margin: 0 0 16px;
  font-size: 14px;
  letter-spacing: 0.02em;
  color: var(--ink-2);
}

.plan-price {
  margin: 0 0 14px;
  font-size: clamp(38px, 4.4vw, 54px);
  font-weight: 600;
  font-variant-numeric: tabular-nums;
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--ink);
}

.plan-desc {
  margin: 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--ink-3);
}

.price-notes {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px clamp(24px, 4vw, 56px);
  margin: 26px 0 0;
  padding: 0;
  list-style: none;
  font-size: 13.5px;
  line-height: 1.85;
  color: var(--ink-2);
}

.price-notes li {
  position: relative;
  padding-left: 14px;
}

.price-notes li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.95em;
  width: 5px;
  height: 1px;
  background: var(--line-2);
}

/* ---------- 常见问题 ---------- */

.faq {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0 clamp(32px, 5vw, 72px);
  margin: 0;
}

.faq > div {
  padding: 20px 0 22px;
  border-top: 1px solid var(--line);
}

.faq dt {
  margin: 0 0 8px;
  font-size: 16px;
  font-weight: 600;
  line-height: 1.6;
}

.faq dd {
  margin: 0;
  font-size: 15px;
  line-height: 1.85;
  color: var(--ink-2);
}

/* ---------- 关于本站 / 协议入口 ---------- */

.about {
  display: grid;
  grid-template-columns: minmax(0, 1.1fr) minmax(0, 0.9fr);
  gap: clamp(28px, 4vw, 56px);
  align-items: start;
}

.about p {
  margin: 0 0 14px;
  max-width: 40em;
  font-size: 15.5px;
  line-height: 1.9;
  color: var(--ink-2);
}

.doc-links {
  border-top: 1px solid var(--line);
}

.doc-link {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 16px;
  padding: 16px 0;
  border-bottom: 1px solid var(--line);
  color: var(--ink);
  font-size: 15.5px;
  text-decoration: none;
}

.doc-link:hover {
  color: var(--brand-ink);
  text-decoration: underline;
  text-underline-offset: 4px;
}

.doc-link span {
  flex: none;
  color: var(--ink-3);
  font-size: 12.5px;
}

/* ---------- 页脚 ---------- */

.site-foot {
  margin-top: clamp(56px, 7vw, 96px);
  padding: clamp(40px, 5vw, 60px) 0 26px;
  background: #101714;
  color: #cfd7cf;
}

.foot-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.85fr);
  gap: clamp(28px, 4vw, 48px);
  padding-bottom: 30px;
  border-bottom: 1px solid rgba(246, 250, 246, 0.14);
}

.foot-word {
  margin: 0 0 8px;
  font-size: clamp(26px, 2.6vw, 32px);
  font-weight: 700;
  letter-spacing: -0.02em;
  color: #f3f7f2;
}

.foot-tag {
  margin: 0 0 18px;
  font-size: 14px;
  line-height: 1.7;
  color: #96a398;
}

.foot-links {
  display: flex;
  flex-wrap: wrap;
  gap: 20px;
  margin: 0;
}

.foot-links a {
  padding-bottom: 2px;
  border-bottom: 1px solid rgba(216, 223, 215, 0.35);
  color: #d8dfd7;
  font-size: 13.5px;
  text-decoration: none;
}

.foot-links a:hover {
  color: #ffffff;
  border-color: #ffffff;
}

.foot-info {
  display: grid;
  gap: 10px;
  align-content: start;
  font-size: 14px;
  line-height: 1.75;
}

.foot-info p {
  margin: 0;
}

.foot-info a {
  padding-bottom: 1px;
  border-bottom: 1px solid rgba(237, 242, 236, 0.35);
  color: #edf2ec;
  text-decoration: none;
}

.foot-info a:hover {
  color: #ffffff;
  border-color: #ffffff;
}

.foot-base {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 10px 24px;
  padding-top: 20px;
  font-size: 12.5px;
  line-height: 1.7;
  color: #8c998f;
}

.foot-base p {
  margin: 0;
}

/* ---------- 协议页 ---------- */

.legal {
  padding-top: clamp(40px, 5.5vw, 72px);
}

.legal-head {
  padding-bottom: 26px;
  border-bottom: 1px solid var(--line);
}

.legal-head .sec-label {
  margin: 0 0 14px;
  grid-row: auto;
}

.legal-head h1 {
  margin: 0 0 12px;
  font-size: clamp(32px, 4.2vw, 52px);
  font-weight: 700;
  line-height: 1.14;
  letter-spacing: -0.02em;
}

.legal-meta {
  margin: 0;
  font-size: 13px;
  line-height: 1.8;
  color: var(--ink-3);
}

.legal-layout {
  display: grid;
  grid-template-columns: 190px minmax(0, 1fr);
  gap: clamp(28px, 5vw, 64px);
  align-items: start;
  padding-top: clamp(28px, 4vw, 44px);
}

.toc {
  position: sticky;
  top: 94px;
  padding-left: 16px;
  border-left: 1px solid var(--line);
  font-size: 13px;
  line-height: 1.7;
}

.toc p {
  margin: 0 0 10px;
  font-size: 12px;
  color: var(--ink-3);
}

.toc ol {
  display: grid;
  gap: 8px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.toc a {
  color: var(--ink-2);
  text-decoration: none;
}

.toc a:hover {
  color: var(--brand-ink);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.legal-body {
  max-width: 74ch;
  font-size: 15.5px;
  line-height: 1.95;
  color: var(--ink-2);
}

.legal-body h2 {
  margin: clamp(32px, 4vw, 44px) 0 12px;
  font-size: 19px;
  font-weight: 600;
  line-height: 1.55;
  letter-spacing: 0.01em;
  color: var(--ink);
  scroll-margin-top: 92px;
}

.legal-body h2:first-of-type {
  margin-top: 0;
}

.legal-body p {
  margin: 0 0 12px;
}

.legal-body ul {
  margin: 0 0 12px;
  padding-left: 1.35em;
}

.legal-body li {
  margin: 0 0 6px;
}

.legal-body strong {
  color: var(--ink);
  font-weight: 600;
}

.legal-intro {
  margin: 0 0 8px;
  padding: 18px 0;
  border-bottom: 1px solid var(--line);
  color: var(--ink-2);
}

.contact-block {
  margin: 18px 0 0;
  padding: 18px 20px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
  font-size: 14.5px;
  line-height: 2;
}

/* ---------- 进场（仅首屏，一次） ---------- */

@media (prefers-reduced-motion: no-preference) {
  .hero-copy > * {
    animation: rise 0.7s cubic-bezier(0.2, 0.7, 0.2, 1) both;
  }

  .hero-copy > :nth-child(2) {
    animation-delay: 0.05s;
  }

  .hero-copy > :nth-child(3) {
    animation-delay: 0.1s;
  }

  .hero-copy > :nth-child(4) {
    animation-delay: 0.15s;
  }

  .hero-copy > :nth-child(5) {
    animation-delay: 0.2s;
  }

  .session {
    animation: fade 0.8s ease 0.15s both;
  }
}

@keyframes rise {
  from {
    opacity: 0;
    transform: translateY(14px);
  }
  to {
    opacity: 1;
    transform: none;
  }
}

@keyframes fade {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

/* ---------- 响应式 ---------- */

@media (max-width: 1080px) {
  .hero {
    grid-template-columns: minmax(0, 1fr);
    gap: clamp(28px, 4vw, 40px);
  }

  .session {
    max-width: 640px;
  }
}

@media (max-width: 900px) {
  .sec-head {
    grid-template-columns: minmax(0, 1fr);
    gap: 0;
  }

  .sec-label {
    grid-row: auto;
    margin: 0 0 10px;
  }

  .sec-head h2,
  .sec-intro {
    grid-column: 1;
  }

  .feature {
    grid-template-columns: minmax(0, 1fr);
    gap: 8px;
  }

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

  .toc {
    position: static;
    order: -1;
    padding: 16px 0 0;
    border-left: 0;
    border-top: 1px solid var(--line);
  }

  .toc ol {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 8px 20px;
  }
}

@media (max-width: 720px) {
  .head-inner {
    height: 62px;
    gap: 14px;
  }

  .head-tag {
    display: none;
  }

  .nav {
    gap: 16px;
  }

  .nav a {
    font-size: 13px;
  }

  .nav a.opt {
    display: none;
  }

  .hero-copy h1 {
    font-size: clamp(54px, 14vw, 76px);
  }

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

  .fact + .fact {
    padding-left: 0;
    border-left: 0;
    border-top: 1px solid var(--line);
  }

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

  .flow li {
    padding: 22px 0 6px;
  }

  .flow li + li {
    padding-left: 0;
    border-left: 0;
    border-top: 1px solid var(--line);
  }

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

  .plan {
    padding: 24px 0;
    border-bottom: 1px solid var(--line-2);
  }

  .plan + .plan {
    padding-left: 0;
    border-left: 0;
  }

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

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

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

  .track {
    grid-template-columns: minmax(0, 1fr);
    gap: 8px;
  }

  .wave {
    height: 48px;
  }

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

@media (max-width: 420px) {
  .brand {
    font-size: 17px;
  }

  .brand svg {
    width: 20px;
    height: 20px;
  }

  .nav {
    gap: 13px;
  }

  .nav a {
    font-size: 12.5px;
  }

  .plan-price {
    font-size: 40px;
  }

  .foot-base {
    display: grid;
  }
}

/* ---------- 打印 ---------- */

@media print {
  .site-head,
  .skip {
    display: none;
  }

  body {
    background: #ffffff;
  }

  .legal-body {
    max-width: none;
  }

  .site-foot {
    margin-top: 32px;
    background: #ffffff;
    color: #141a16;
  }

  .foot-word,
  .foot-info a,
  .foot-links a {
    color: #141a16;
  }

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