/* 谱记落地页 — 净色画布·墨·朱砂 (与 App Theme 同源, R10 起去纸张暖调)
   排版优先, 单一强调色, 动效克制且尊重 reduced-motion */

:root {
  --paper: #f5f5f7;
  --paper-deep: #ebebef;
  --ink: #17171b;
  --ink-2: #4d4d54;
  --hairline: rgba(23, 23, 27, 0.14);
  --cinnabar: #c8401f;
  --cinnabar-deep: #ab3517;
  --verdigris: #2e7d6b;
  --radius: 18px;
  --w: min(1180px, calc(100vw - 48px));
  font-size: 17px;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

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

body {
  font-family: -apple-system, "SF Pro Text", "PingFang SC", "Hiragino Sans GB",
    "Noto Sans CJK SC", sans-serif;
  background: var(--paper);
  color: var(--ink);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3 { line-height: 1.18; letter-spacing: -0.015em; font-weight: 650; }

img { display: block; max-width: 100%; height: auto; }

/* ---- 导航: 64px 单行 ---- */

.nav {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  gap: 28px;
  height: 64px;
  padding: 0 max(24px, calc((100vw - 1180px) / 2));
  background: color-mix(in srgb, var(--paper) 86%, transparent);
  backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--hairline);
}

.nav-mark {
  display: flex;
  align-items: center;
  gap: 9px;
  font-weight: 700;
  font-size: 1.12rem;
  color: var(--ink);
  text-decoration: none;
}

.mark-dot {
  width: 11px;
  height: 11px;
  border-radius: 50%;
  background: var(--cinnabar);
  display: inline-block;
}

.nav-links {
  display: flex;
  gap: 22px;
  margin-left: auto;
}

.nav-links a {
  color: var(--ink-2);
  text-decoration: none;
  font-size: 0.94rem;
}
.nav-links a:hover { color: var(--ink); }

/* ---- 按钮: 单一意图单一文案 ---- */

.btn {
  display: inline-block;
  border-radius: 999px;
  padding: 11px 22px;
  font-size: 0.97rem;
  font-weight: 600;
  text-decoration: none;
  transition: transform 0.15s ease, background 0.15s ease;
}
.btn:active { transform: translateY(1px) scale(0.99); }

.btn-primary { background: var(--cinnabar); color: #fff; }
.btn-primary:hover { background: var(--cinnabar-deep); }

.btn-ghost {
  color: var(--ink);
  border: 1px solid var(--hairline);
  background: transparent;
}
.btn-ghost:hover { border-color: var(--ink-2); }

.btn-lg { padding: 15px 34px; font-size: 1.06rem; }

/* ---- 主张区: 55/45 非对称, 首屏完整 ---- */

.hero {
  position: relative;
  display: grid;
  grid-template-columns: 11fr 9fr;
  gap: 40px;
  align-items: center;
  width: var(--w);
  margin: 0 auto;
  /* 首屏完整, 但在超高视口上不无限拉伸 */
  min-height: min(calc(100dvh - 64px), 860px);
  padding: 28px 0 0;
  overflow: visible;
}

.hero-copy { padding-bottom: 7vh; }

.hero h1 {
  font-size: clamp(3.2rem, 7.2vw, 5.6rem);
  font-weight: 720;
}

.hero h1 em {
  font-style: normal;
  color: var(--cinnabar);
}

.hero-sub {
  margin-top: 22px;
  font-size: 1.18rem;
  color: var(--ink-2);
  max-width: 30ch;
}

.hero-actions {
  display: flex;
  gap: 14px;
  margin-top: 34px;
  flex-wrap: wrap;
}

.hero-device {
  position: relative;
  z-index: 1;
  align-self: end;
  max-width: 372px;
  justify-self: center;
}

.hero-device img {
  border-radius: 34px;
  border: 1px solid var(--hairline);
  box-shadow:
    0 2px 6px rgba(30, 20, 10, 0.08),
    0 32px 64px -24px rgba(30, 20, 10, 0.32);
}

/* 纸面上的五线: 品牌母题, 不是装饰网格 */
.hero-staff {
  position: absolute;
  inset: auto 0 14vh 0;
  height: 96px;
  background: repeating-linear-gradient(
    to bottom,
    transparent 0 23px,
    var(--hairline) 23px 24px
  );
  mask-image: linear-gradient(to right, transparent, #000 18%, #000 56%, transparent 78%);
  pointer-events: none;
}

/* ---- 事实条 ---- */

.facts {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  width: var(--w);
  margin: 0 auto;
  border-top: 1px solid var(--hairline);
  border-bottom: 1px solid var(--hairline);
}

.fact {
  display: flex;
  align-items: baseline;
  gap: 14px;
  padding: 26px 8px;
}

.fact + .fact { border-left: 1px solid var(--hairline); padding-left: 28px; }

.fact strong {
  font-size: 2.6rem;
  font-weight: 720;
  letter-spacing: -0.04em;
  color: var(--cinnabar);
  font-variant-numeric: tabular-nums;
}

.fact span { color: var(--ink-2); font-size: 0.95rem; max-width: 17ch; }

/* ---- 工作流 ---- */

.flow { width: var(--w); margin: 110px auto 0; }

.flow h2 { font-size: clamp(1.9rem, 3.6vw, 2.7rem); max-width: 16ch; }

.flow-steps {
  list-style: none;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 0;
  margin-top: 48px;
  border-top: 1px solid var(--hairline);
}

.flow-steps li { padding: 30px 30px 8px 0; }

.flow-steps li + li { border-left: 1px solid var(--hairline); padding-left: 30px; }

.flow-num {
  display: inline-block;
  font-size: 0.9rem;
  font-weight: 700;
  color: var(--cinnabar);
  border: 1px solid currentColor;
  border-radius: 999px;
  padding: 3px 13px;
  margin-bottom: 18px;
}

.flow-steps h3 { font-size: 1.22rem; margin-bottom: 10px; }
.flow-steps p { color: var(--ink-2); font-size: 0.97rem; max-width: 30ch; }

/* ---- 诚实的 AI: 墨色宣言 ---- */

.honest {
  margin-top: 130px;
  background: var(--ink);
  color: var(--paper);
  text-align: center;
  padding: 96px 24px 104px;
}

.honest-kicker {
  font-size: 0.82rem;
  letter-spacing: 0.22em;
  color: color-mix(in srgb, var(--paper) 55%, transparent);
  text-transform: uppercase;
}

.honest h2 {
  font-size: clamp(2rem, 4.4vw, 3.2rem);
  margin-top: 18px;
}

.honest-body {
  max-width: 36em;
  margin: 22px auto 0;
  color: color-mix(in srgb, var(--paper) 78%, transparent);
}

.ink-scale {
  display: flex;
  justify-content: center;
  gap: clamp(20px, 6vw, 64px);
  margin-top: 56px;
}

.ink {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 14px;
  font-size: 0.92rem;
  color: color-mix(in srgb, var(--paper) 72%, transparent);
}

.ink-note {
  width: 34px;
  height: 34px;
  border-radius: 50% 50% 50% 50% / 58% 58% 42% 42%;
  transform: rotate(-14deg);
}

.ink-high .ink-note { background: var(--paper); }
.ink-mid .ink-note { background: color-mix(in srgb, var(--paper) 52%, transparent); }
.ink-low .ink-note {
  background: transparent;
  border: 2px dashed color-mix(in srgb, var(--paper) 60%, transparent);
}

/* ---- 组合格: 1 大 + 3 小, 背景各异 ---- */

.grid-feature {
  display: grid;
  grid-template-columns: 7fr 5fr;
  gap: 18px;
  width: var(--w);
  margin: 120px auto 0;
}

.gf-cell {
  border: 1px solid var(--hairline);
  border-radius: var(--radius);
  padding: 34px;
  background: #fffdf8;
}

.gf-cell h3 { font-size: 1.3rem; margin-bottom: 10px; }
.gf-cell p { color: var(--ink-2); font-size: 0.98rem; }

.gf-wide { display: flex; flex-direction: column; }
.gf-wide p { max-width: 44ch; }

.gf-wide img {
  margin-top: 28px;
  border-radius: 12px;
  border: 1px solid var(--hairline);
  /* 裁掉 iPad 截图下方空白, 聚焦谱面 */
  aspect-ratio: 16 / 10;
  object-fit: cover;
  object-position: top;
}

.gf-col { display: flex; flex-direction: column; gap: 18px; }
.gf-col .gf-cell { flex: 1; }

.gf-tint {
  background: color-mix(in srgb, var(--cinnabar) 7%, var(--paper));
  border-color: color-mix(in srgb, var(--cinnabar) 26%, transparent);
}

.gf-dark { background: var(--ink); border-color: var(--ink); }
.gf-dark h3 { color: var(--paper); }
.gf-dark p { color: color-mix(in srgb, var(--paper) 72%, transparent); }

/* ---- 练习: 唯一图文分屏 ---- */

.practice {
  display: grid;
  grid-template-columns: 5fr 7fr;
  gap: clamp(32px, 6vw, 88px);
  align-items: center;
  width: var(--w);
  margin: 130px auto 0;
}

.practice-shot { max-width: 330px; justify-self: center; }

.practice-shot img {
  border-radius: 30px;
  border: 1px solid var(--hairline);
  box-shadow: 0 28px 56px -26px rgba(30, 20, 10, 0.3);
}

.practice h2 { font-size: clamp(1.9rem, 3.6vw, 2.6rem); max-width: 15ch; }

.practice-list {
  list-style: none;
  margin-top: 30px;
  border-top: 1px solid var(--hairline);
}

.practice-list li {
  padding: 16px 0;
  border-bottom: 1px solid var(--hairline);
  color: var(--ink-2);
  font-size: 1.0rem;
}

.practice-list strong { color: var(--ink); font-weight: 650; margin-right: 10px; }

/* ---- 导出 ---- */

.export { width: var(--w); margin: 130px auto 0; }
.export h2 { font-size: clamp(1.9rem, 3.6vw, 2.6rem); }
.export-sub { color: var(--ink-2); margin-top: 12px; max-width: 40ch; }

.export-row {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 36px;
}

.fmt {
  display: flex;
  align-items: center;
  gap: 12px;
  border: 1px solid var(--hairline);
  border-radius: 999px;
  padding: 10px 20px 10px 10px;
  font-size: 0.92rem;
  color: var(--ink-2);
  background: #fffdf8;
}

.fmt strong {
  display: inline-grid;
  place-items: center;
  width: 46px;
  height: 46px;
  border-radius: 50%;
  background: var(--ink);
  color: var(--paper);
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.02em;
}

/* ---- 隐私安静带 ---- */

.privacy {
  margin: 130px auto 0;
  width: var(--w);
  border-block: 1px solid var(--hairline);
  padding: 56px 0;
}

.privacy p {
  font-size: clamp(1.25rem, 2.6vw, 1.7rem);
  font-weight: 600;
  max-width: 30em;
}

.privacy span {
  display: block;
  margin-top: 14px;
  font-size: 0.98rem;
  font-weight: 400;
  color: var(--ink-2);
}

/* ---- 下载 ---- */

.download {
  width: var(--w);
  margin: 120px auto;
  text-align: center;
  background: var(--paper-deep);
  border-radius: calc(var(--radius) * 1.6);
  padding: 84px 24px;
}

.download h2 { font-size: clamp(2rem, 4.4vw, 3rem); }
.download p { color: var(--ink-2); margin: 16px 0 30px; }
.download-foot { font-size: 0.85rem; margin-top: 18px; }

/* ---- 页脚 ---- */

.footer {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 34px;
  width: var(--w);
  margin: 0 auto;
  padding: 30px 0 44px;
  border-top: 1px solid var(--hairline);
  color: var(--ink-2);
  font-size: 0.88rem;
  align-items: center;
}

.footer .mark-dot { width: 8px; height: 8px; margin-right: 7px; }

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

.footer a:hover { color: var(--ink); }

/* ---- 法律与支持页 ---- */

.legal-page {
  width: min(820px, calc(100vw - 48px));
  margin: 84px auto 120px;
}

.legal-page h1 {
  font-size: clamp(2.2rem, 5vw, 3.4rem);
  margin-bottom: 12px;
}

.legal-page h2 {
  font-size: 1.25rem;
  margin: 38px 0 10px;
}

.legal-page p {
  color: var(--ink-2);
  margin-top: 10px;
}

.legal-page a {
  color: var(--cinnabar);
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
}

.legal-updated {
  font-size: 0.94rem;
  color: var(--ink-2);
}

/* ---- 进场揭示 (IntersectionObserver 配合) ---- */

.reveal {
  opacity: 0;
  transform: translateY(22px);
  transition: opacity 0.7s ease, transform 0.7s cubic-bezier(0.22, 1, 0.36, 1);
}

.reveal.is-in { opacity: 1; transform: none; }

@media (prefers-reduced-motion: reduce) {
  .reveal { opacity: 1; transform: none; transition: none; }
  .btn { transition: none; }
}

/* ---- 响应式 ---- */

@media (max-width: 920px) {
  .nav-links { display: none; }

  .hero {
    grid-template-columns: 1fr;
    min-height: auto;
    padding-top: 48px;
    gap: 56px;
  }
  .hero-copy { padding-bottom: 0; }
  .hero-staff { display: none; }
  .hero-device { max-width: 300px; }

  .facts { grid-template-columns: 1fr; }
  .fact + .fact { border-left: 0; border-top: 1px solid var(--hairline); padding-left: 8px; }

  .flow-steps { grid-template-columns: 1fr; }
  .flow-steps li + li { border-left: 0; border-top: 1px solid var(--hairline); padding-left: 0; }

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

  .practice { grid-template-columns: 1fr; }
  .practice-shot { order: 2; }
}