/* ============================================================
   paperdemo · 学术校样风
   米白纸底 + 墨绿 + 琥珀。衬线大标题，等宽小标签。
   ============================================================ */

:root {
  --paper:      #F5F1E6;   /* 页面底：米白纸 */
  --paper-2:    #EDE7D6;   /* 下沉面 */
  --card:       #FCFAF3;   /* 卡面 */
  --ink:        #1C2B26;   /* 标题墨色 */
  --ink-2:      #45564F;   /* 正文 */
  --ink-3:      #71827A;   /* 弱字 */
  --green:      #1F4A3D;   /* 主色：墨绿 */
  --green-deep: #142E26;   /* 暗带 */
  --green-soft: #DCE7DF;   /* 墨绿浅底 */
  --amber:      #B98A2F;   /* 强调金 */
  --amber-deep: #9A6F1F;
  --amber-soft: #F3E8CF;
  --warn:       #A8542F;   /* 提示橙（仅「模拟演示」标记） */
  --line:       #D9D2BC;   /* 发丝线 */
  --line-2:     #C6BC9C;
  --serif: Georgia, "Times New Roman", "Songti SC", "SimSun", serif;
  --sans:  -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
           "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --mono:  ui-monospace, "Cascadia Mono", "SF Mono", Consolas,
           "Courier New", monospace;
  --shadow: 0 1px 2px rgba(28,43,38,.05), 0 12px 32px -12px rgba(28,43,38,.14);
  --ease:  cubic-bezier(.22,.8,.28,1);
}

/* ---------- reset ---------- */
*, *::before, *::after { box-sizing: border-box; }
* { margin: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.75;
  color: var(--ink-2);
  background: var(--paper);
  -webkit-font-smoothing: antialiased;
  text-wrap: pretty;
}
img, svg { display: block; max-width: 100%; }
a { color: inherit; text-decoration: none; }
button { font: inherit; color: inherit; background: none; border: 0; cursor: pointer; }
code { font-family: var(--mono); font-size: .88em; background: var(--green-soft); padding: .1em .38em; border-radius: 3px; color: var(--green); }

.wrap { width: min(1120px, calc(100% - 48px)); margin-inline: auto; }
.wrap-narrow { width: min(820px, calc(100% - 48px)); }

/* ---------- 通用字级 ---------- */
.eyebrow {
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: .18em;
  color: var(--amber-deep);
  margin-bottom: 18px;
}
.eyebrow-dark { color: #D8B46A; }

h1, h2, h3 { font-family: var(--serif); color: var(--ink); font-weight: 700; line-height: 1.28; }
h1 { font-size: clamp(34px, 4.6vw, 54px); letter-spacing: .01em; }
h2 { font-size: clamp(26px, 3.2vw, 38px); }
h3 { font-size: 19px; }

.hl {
  position: relative;
  z-index: 0;
  white-space: nowrap;
}
.hl::before {
  content: "";
  position: absolute;
  left: -.06em; right: -.06em; bottom: .06em;
  height: .42em;
  background: var(--amber-soft);
  z-index: -1;
  transform: rotate(-.8deg);
}

/* ---------- 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 15px;
  font-weight: 600;
  padding: 12px 22px;
  border-radius: 4px;
  border: 1px solid transparent;
  transition: transform .18s var(--ease), box-shadow .18s var(--ease),
              background-color .18s var(--ease), color .18s var(--ease),
              border-color .18s var(--ease);
  will-change: transform;
}
.btn:active { transform: translateY(1px); }
.btn-sm { padding: 9px 16px; font-size: 14px; }
.btn-primary { background: var(--green); color: #F5F1E6; }
.btn-primary:hover { background: #183E33; transform: translateY(-1px); box-shadow: 0 8px 20px -8px rgba(20,46,38,.45); }
.btn-ghost { border-color: var(--line-2); color: var(--ink); background: transparent; }
.btn-ghost:hover { border-color: var(--green); color: var(--green); transform: translateY(-1px); }
.btn-amber { background: var(--amber); color: #FFF9EC; }
.btn-amber:hover { background: var(--amber-deep); transform: translateY(-1px); box-shadow: 0 8px 20px -8px rgba(154,111,31,.5); }
.btn-line { border-color: rgba(245,241,230,.4); color: #F5F1E6; }
.btn-line:hover { border-color: #F5F1E6; transform: translateY(-1px); }

/* ============================================================
   NAV
   ============================================================ */
.nav {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(245,241,230,.88);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid transparent;
  transition: border-color .25s, box-shadow .25s;
}
.nav.scrolled { border-bottom-color: var(--line); box-shadow: 0 2px 16px -8px rgba(28,43,38,.12); }
.nav-in { display: flex; align-items: center; gap: 28px; height: 64px; }
.brand { display: inline-flex; align-items: center; gap: 10px; }
.brand-mark { width: 24px; height: 24px; color: var(--green); flex: none; }
.brand-mark svg { width: 100%; height: 100%; }
.brand-text { display: flex; flex-direction: column; line-height: 1.2; }
.brand-name { font-family: var(--serif); font-weight: 700; font-size: 17px; color: var(--ink); letter-spacing: .01em; }
.brand-sub { font-family: var(--mono); font-size: 10.5px; letter-spacing: .06em; color: var(--ink-3); }
.nav-links { display: flex; gap: 26px; margin-left: auto; }
.nav-links a {
  font-size: 14.5px;
  color: var(--ink-2);
  position: relative;
  padding: 4px 0;
  transition: color .18s;
}
.nav-links a::after {
  content: "";
  position: absolute;
  left: 0; right: 100%; bottom: 0;
  height: 1.5px;
  background: var(--green);
  transition: right .22s var(--ease);
}
.nav-links a:hover { color: var(--green); }
.nav-links a:hover::after { right: 0; }
.nav-cta { flex: none; }
.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  padding: 8px;
  margin-left: auto;
}
.nav-toggle span { width: 20px; height: 2px; background: var(--ink); transition: transform .2s var(--ease); }
.nav-toggle[aria-expanded="true"] span:first-child { transform: translateY(3.5px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] span:last-child { transform: translateY(-3.5px) rotate(-45deg); }
.mobile-menu { border-top: 1px solid var(--line); background: var(--paper); padding: 8px 24px 16px; }
.mobile-menu a { display: block; padding: 11px 0; font-size: 15px; border-bottom: 1px dashed var(--line); }
.mobile-menu a:last-child { border-bottom: 0; }

/* ============================================================
   HERO
   ============================================================ */
.hero { position: relative; padding: clamp(48px, 7vw, 88px) 0 0; overflow: hidden; }
.hero::before {   /* 纸上极淡的纤维噪点 */
  content: "";
  position: absolute; inset: 0;
  background:
    repeating-linear-gradient(0deg, transparent 0 3px, rgba(28,43,38,.012) 3px 4px),
    repeating-linear-gradient(90deg, transparent 0 3px, rgba(28,43,38,.012) 3px 4px);
  pointer-events: none;
}
.hero-in {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1.05fr) minmax(0, 1fr);
  gap: clamp(32px, 5vw, 72px);
  align-items: center;
  padding-bottom: clamp(48px, 6vw, 72px);
}
.hero-copy h1 { margin-bottom: 22px; }
.lede { font-size: 17px; max-width: 30em; }
.hero-acts { display: flex; flex-wrap: wrap; gap: 14px; margin-top: 30px; }
.hero-note {
  font-family: var(--mono);
  font-size: 12px;
  color: var(--ink-3);
  margin-top: 18px;
  letter-spacing: .02em;
}

/* ---------- 手稿卡 ---------- */
.msheet {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 6px;
  box-shadow: var(--shadow);
  overflow: hidden;
  position: relative;
}
.msheet::before {   /* 左侧装订线 */
  content: "";
  position: absolute;
  left: 0; top: 0; bottom: 0;
  width: 3px;
  background: var(--green);
}
.msheet-head {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 13px 18px;
  border-bottom: 1px solid var(--line);
  background: var(--paper-2);
}
.msheet-tag {
  font-family: var(--mono);
  font-size: 10.5px;
  letter-spacing: .16em;
  background: var(--green);
  color: #F5F1E6;
  padding: 3px 8px;
  border-radius: 2px;
}
.msheet-title { font-family: var(--mono); font-size: 12.5px; color: var(--ink-2); }
.msheet-clock {
  margin-left: auto;
  font-family: var(--mono);
  font-size: 11.5px;
  color: var(--ink-3);
  display: inline-flex;
  align-items: center;
  gap: 7px;
}
.msheet-clock::before {
  content: "";
  width: 7px; height: 7px;
  border-radius: 50%;
  background: var(--amber);
  box-shadow: 0 0 0 3px rgba(185,138,47,.18);
}
.msheet-body { padding: 24px 22px 22px; position: relative; }

.mblock { position: relative; }
.mblock-label {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: .14em;
  color: var(--ink-3);
  margin-bottom: 8px;
}
.mblock p {
  font-family: var(--serif);
  font-size: 16.5px;
  line-height: 1.9;
  color: var(--ink);
}
.m-origin p { color: var(--ink-2); }

/* 边注：绿色手写感 */
.mnote {
  font-family: var(--serif);
  font-style: italic;
  font-size: 13px;
  line-height: 1.5;
  color: var(--green);
  border-left: 2px solid var(--green);
  padding: 2px 0 2px 10px;
  margin-top: 12px;
  opacity: 0;
  transform: translateX(-6px);
  transition: opacity .4s var(--ease) .1s, transform .4s var(--ease) .1s;
}
.msheet.on .mnote { opacity: 1; transform: none; }

/* 箭头 + 按钮 */
.marrow { display: flex; align-items: center; gap: 14px; margin: 18px 0; }
.marrow-line { flex: 1; height: 1px; background: var(--line-2); }
.mbtn {
  font-family: var(--mono);
  font-size: 12.5px;
  letter-spacing: .04em;
  background: var(--amber);
  color: #FFF9EC;
  padding: 8px 16px;
  border-radius: 3px;
  white-space: nowrap;
  transition: background-color .18s, transform .18s var(--ease);
}
.mbtn:hover { background: var(--amber-deep); transform: translateY(-1px); }
.mbtn.done { background: var(--green-soft); color: var(--green); }

/* 改写结果：未触发时收起 */
.m-result {
  max-height: 0;
  opacity: 0;
  overflow: hidden;
  transition: max-height .5s var(--ease), opacity .35s var(--ease);
}
.msheet.on .m-result { max-height: 220px; opacity: 1; }
.m-result p em { font-style: normal; background: linear-gradient(transparent 62%, var(--amber-soft) 62%); }

/* 仪表 */
.mgauge {
  margin-top: 20px;
  padding: 14px 16px;
  background: var(--green-soft);
  border-radius: 4px;
}
.mgauge-row { display: flex; align-items: baseline; justify-content: space-between; }
.mgauge-key { font-family: var(--mono); font-size: 12px; letter-spacing: .1em; color: var(--green); }
.mgauge-vals { display: inline-flex; align-items: baseline; gap: 8px; }
.mgauge-vals b { font-family: var(--mono); font-size: 19px; color: var(--ink); }
.mgauge-vals b:last-child { color: var(--green); }
.mgauge-vals i { font-style: normal; color: var(--ink-3); }
.mgauge-bars { margin-top: 10px; display: grid; gap: 7px; }
.mgauge-bar { height: 7px; background: rgba(28,43,38,.1); border-radius: 4px; overflow: hidden; }
.mgauge-bar span { display: block; height: 100%; background: var(--warn); border-radius: 4px; transition: width .8s var(--ease); }
.mgauge-bar-ok span { background: var(--green); }
.mgauge-foot { font-family: var(--mono); font-size: 10.5px; color: var(--ink-3); margin-top: 9px; }

/* ---------- ticker ---------- */
.ticker {
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  background: var(--paper-2);
  overflow: hidden;
  padding: 11px 0;
}
.ticker-track {
  display: inline-flex;
  gap: 22px;
  white-space: nowrap;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: .2em;
  color: var(--ink-3);
  animation: ticker 36s linear infinite;
}
@keyframes ticker {
  from { transform: translateX(0); }
  to   { transform: translateX(-50%); }
}

/* ============================================================
   SECTION 通用
   ============================================================ */
.section { padding: clamp(56px, 7.5vw, 96px) 0; }
.section-tint { background: var(--paper-2); }
.section-dark { background: var(--green-deep); }
.section-dark h2, .section-dark h3 { color: #F2EFE3; }
.section-dark .sec-lede { color: #B9C6BE; }
.sec-head { max-width: 640px; margin-bottom: clamp(32px, 4vw, 52px); }
.sec-head h2 { margin-bottom: 16px; }
.sec-lede { font-size: 16.5px; }

/* ---------- 能力网格 ---------- */
.caps-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: 6px;
  overflow: hidden;
}
.cap {
  background: var(--card);
  padding: 26px 24px 22px;
  position: relative;
  transition: background-color .22s var(--ease);
}
.cap::before {
  content: "";
  position: absolute;
  left: 0; top: 0; bottom: 0;
  width: 3px;
  background: var(--green);
  transform: scaleY(0);
  transform-origin: top;
  transition: transform .28s var(--ease);
}
.cap:hover { background: #FFFEF9; }
.cap:hover::before { transform: scaleY(1); }
.cap-idx {
  font-family: var(--mono);
  font-size: 12px;
  color: var(--amber-deep);
  letter-spacing: .08em;
  display: block;
  margin-bottom: 12px;
}
.cap h3 { margin-bottom: 8px; transition: color .2s; }
.cap:hover h3 { color: var(--green); }
.cap p { font-size: 14.5px; line-height: 1.7; }
.cap-tags { display: flex; flex-wrap: wrap; gap: 6px; margin-top: 14px; }
.cap-tags span {
  font-family: var(--mono);
  font-size: 11px;
  color: var(--green);
  background: var(--green-soft);
  padding: 2.5px 8px;
  border-radius: 2px;
}
.cap-tags .t-warn { color: var(--warn); background: #F6E7DA; }

/* ============================================================
   改写演示（暗带）
   ============================================================ */
.demo-panel {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto minmax(0, 1fr);
  gap: clamp(18px, 3vw, 40px);
  align-items: stretch;
}
.demo-col {
  background: rgba(245,241,230,.05);
  border: 1px solid rgba(245,241,230,.14);
  border-radius: 6px;
  padding: 24px 24px 20px;
}
.demo-col-after { border-color: rgba(185,138,47,.45); background: rgba(185,138,47,.07); }
.demo-col-head {
  display: flex;
  align-items: center;
  gap: 9px;
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: .06em;
  color: #B9C6BE;
  margin-bottom: 16px;
}
.dot { width: 8px; height: 8px; border-radius: 50%; flex: none; }
.dot-mute { background: #8A978F; }
.dot-ok { background: var(--amber); }
.demo-text {
  font-family: var(--serif);
  font-size: 17px;
  line-height: 2;
  color: #F2EFE3;
  min-height: 5.2em;
}
.demo-col-after .demo-text { color: #FFF9EC; }
.demo-marks { list-style: none; padding: 0; margin-top: 16px; display: grid; gap: 7px; }
.demo-marks li {
  font-size: 13px;
  color: #93A79D;
  padding-left: 18px;
  position: relative;
}
.demo-marks li::before {
  content: "×";
  position: absolute; left: 0;
  color: #B0826A;
  font-family: var(--mono);
}
.demo-marks-ok li { color: #C9BC93; }
.demo-marks-ok li::before { content: "✓"; color: var(--amber); }
.demo-col-after .demo-marks li { opacity: .45; transition: opacity .4s var(--ease) .5s; }
.demo-panel.done .demo-col-after .demo-marks li { opacity: 1; }

.demo-mid {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 12px;
  min-width: 120px;
}
.demo-mid-hint { font-family: var(--mono); font-size: 11px; color: #7E9188; letter-spacing: .04em; }
.demo-foot {
  font-family: var(--mono);
  font-size: 12px;
  color: #8A978F;
  margin-top: 26px;
  letter-spacing: .02em;
}

/* 改写执行动画 */
.demo-col-after .demo-text { transition: filter .5s var(--ease); }
.demo-panel:not(.done) .demo-col-after .demo-text { filter: blur(5px); opacity: .55; }
.demo-panel.done .demo-col-after .demo-text { filter: none; opacity: 1; }

/* ============================================================
   流程
   ============================================================ */
.flow {
  list-style: none;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 20px;
  counter-reset: flow;
}
.flow-step {
  position: relative;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: 24px 22px;
  transition: transform .22s var(--ease), box-shadow .22s var(--ease);
}
.flow-step:hover { transform: translateY(-3px); box-shadow: var(--shadow); }
.flow-step:not(:last-child)::after {   /* 连接线 */
  content: "";
  position: absolute;
  right: -21px; top: 44px;
  width: 22px;
  border-top: 1.5px dashed var(--line-2);
}
.flow-num {
  font-family: var(--serif);
  font-size: 40px;
  font-weight: 700;
  color: var(--green);
  line-height: 1;
  display: block;
  margin-bottom: 14px;
}
.flow-step h3 { font-size: 17.5px; margin-bottom: 7px; }
.flow-step p { font-size: 14px; line-height: 1.7; }

/* ============================================================
   场景
   ============================================================ */
.scenes { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 14px; }
.scene {
  display: flex;
  align-items: center;
  gap: 18px;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: 18px 20px;
  transition: transform .2s var(--ease), border-color .2s;
}
.scene:hover { transform: translateY(-2px); border-color: var(--green); }
.scene-wide { grid-column: 1 / -1; }
.scene-idx {
  font-family: var(--serif);
  font-size: 15px;
  font-weight: 700;
  color: var(--green);
  background: var(--green-soft);
  border: 1px solid rgba(31,74,61,.25);
  border-radius: 50%;
  width: 52px; height: 52px;
  flex: none;
  display: grid;
  place-items: center;
}
.scene h3 { font-size: 16.5px; margin-bottom: 2px; }
.scene p { font-size: 13.5px; }

/* ============================================================
   FAQ
   ============================================================ */
.faq { display: grid; gap: 10px; }
.faq-item {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 6px;
  overflow: hidden;
  transition: border-color .2s;
}
.faq-item[open] { border-color: var(--green); }
.faq-item summary {
  list-style: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 17px 20px;
  cursor: pointer;
  font-family: var(--serif);
  font-size: 16.5px;
  font-weight: 700;
  color: var(--ink);
  transition: color .18s;
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after {
  content: "+";
  font-family: var(--mono);
  font-size: 19px;
  color: var(--green);
  flex: none;
  transition: transform .25s var(--ease);
}
.faq-item[open] summary::after { transform: rotate(45deg); }
.faq-item summary:hover { color: var(--green); }
.faq-item p {
  padding: 0 20px 18px;
  font-size: 14.5px;
  line-height: 1.85;
  max-width: 44em;
}

/* ============================================================
   CTA + FOOTER
   ============================================================ */
.cta { background: var(--green); padding: clamp(64px, 8vw, 104px) 0; text-align: center; }
.cta h2 { color: #F5F1E6; margin-bottom: 30px; }
.cta-acts { justify-content: center; margin-top: 0; }
.cta .btn-primary { background: #F5F1E6; color: var(--green-deep); }
.cta .btn-primary:hover { background: #FFFDF6; }

.footer { background: var(--green-deep); color: #9DB0A7; padding: 40px 0 34px; }
.footer-in { display: grid; gap: 14px; }
.footer-brand {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  font-family: var(--serif);
  font-weight: 700;
  font-size: 16px;
  color: #F2EFE3;
}
.footer-brand .brand-mark { width: 20px; height: 20px; color: #D8B46A; }
.footer-note { font-size: 13px; line-height: 1.8; max-width: 46em; }
.footer-meta { font-family: var(--mono); font-size: 11px; letter-spacing: .18em; color: #5F7A6F; }

/* ============================================================
   滚动显现
   ============================================================ */
.rv {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity .6s var(--ease), transform .6s var(--ease);
}
.rv.in { opacity: 1; transform: none; }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .rv { opacity: 1; transform: none; transition: none; }
  .ticker-track { animation: none; }
  * { transition-duration: .01ms !important; animation-duration: .01ms !important; }
}

/* ============================================================
   响应式
   ============================================================ */
@media (max-width: 960px) {
  .hero-in { grid-template-columns: 1fr; gap: 40px; }
  .caps-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .demo-panel { grid-template-columns: 1fr; }
  .demo-mid { flex-direction: row; padding: 4px 0; }
  .flow { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .flow-step:not(:last-child)::after { display: none; }
}

@media (max-width: 720px) {
  .nav-links, .nav-cta { display: none; }
  .nav-toggle { display: flex; }
  .wrap, .wrap-narrow { width: calc(100% - 40px); }
  .caps-grid { grid-template-columns: 1fr; }
  .scenes { grid-template-columns: 1fr; }
  .flow { grid-template-columns: 1fr; }
  .hero { padding-top: 36px; }
  .msheet-body { padding: 18px 16px 16px; }
  .m-result { max-height: 260px; }
  .demo-col { padding: 18px 16px 16px; }
  .demo-text { font-size: 15.5px; }
  .ticker-track { letter-spacing: .14em; }
}