/* 泼墨书画圈官网样式
   设计取向：宣纸底色 + 墨色正文 + 朱红印章点缀，和 App 内的橙色主色呼应但更克制。
   纯手写 CSS，无框架依赖。 */

:root {
  --ink: #1f2329;
  --ink-2: #454b54;
  --ink-3: #767d87;
  --paper: #fbf8f2;
  --paper-2: #f4efe4;
  --card: #ffffff;
  --seal: #b0352c;
  --seal-soft: #f6e6e2;
  --accent: #e2701f;
  --accent-soft: #fdf0e4;
  --line: #e6ddcc;
  --line-soft: #efe8da;
  --max: 1100px;
  --serif: "Songti SC", "STSong", "Noto Serif SC", "SimSun", serif;
}

* {
  box-sizing: border-box;
}

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

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  font-size: 16px;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
}

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

img {
  max-width: 100%;
}

.wrap {
  max-width: var(--max);
  margin: 0 auto;
  padding: 0 24px;
}

/* ---------------- 顶部导航 ---------------- */

.hd {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(251, 248, 242, 0.94);
  border-bottom: 1px solid var(--line-soft);
  backdrop-filter: saturate(1.2) blur(8px);
}

.hd-in {
  height: 68px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-family: var(--serif);
  font-size: 19px;
  font-weight: 600;
  letter-spacing: 1px;
  white-space: nowrap;
}

.brand img {
  width: 34px;
  height: 34px;
  border-radius: 9px;
  display: block;
}

.nav {
  display: flex;
  gap: 26px;
  font-size: 14.5px;
  color: var(--ink-2);
}

.nav a {
  padding: 4px 0;
  border-bottom: 1px solid transparent;
  transition: color 0.15s, border-color 0.15s;
}

.nav a:hover {
  color: var(--seal);
  border-bottom-color: var(--seal);
}

.nav a.on {
  color: var(--ink);
  border-bottom-color: var(--ink);
}

/* ---------------- 首屏 ---------------- */

.hero {
  padding: 70px 0 76px;
  border-bottom: 1px solid var(--line-soft);
  background: linear-gradient(180deg, #fdfbf6 0%, var(--paper) 100%);
}

.hero-in {
  display: grid;
  grid-template-columns: 1fr 300px;
  gap: 64px;
  align-items: center;
}

.tag {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  padding: 4px 12px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: #fff;
  color: var(--ink-3);
  font-size: 12.5px;
  letter-spacing: 0.3px;
}

.tag i {
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--accent);
  display: block;
}

h1 {
  font-family: var(--serif);
  font-size: 46px;
  line-height: 1.25;
  letter-spacing: 2px;
  margin: 20px 0 10px;
  font-weight: 600;
}

.hero-sub {
  font-family: var(--serif);
  font-size: 20px;
  color: var(--seal);
  letter-spacing: 3px;
  margin: 0 0 20px;
}

.hero-desc {
  font-size: 16.5px;
  color: var(--ink-2);
  margin: 0 0 30px;
  max-width: 520px;
}

.btns {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  height: 44px;
  padding: 0 24px;
  border-radius: 8px;
  font-size: 15px;
  border: 1px solid transparent;
  transition: transform 0.12s, background 0.15s, border-color 0.15s;
}

.btn:active {
  transform: translateY(1px);
}

.btn-solid {
  background: var(--ink);
  color: #fff;
}

.btn-solid:hover {
  background: #0f1216;
}

.btn-ghost {
  border-color: var(--line);
  color: var(--ink-2);
  background: #fff;
}

.btn-ghost:hover {
  border-color: var(--ink-3);
  color: var(--ink);
}

/* 手机外框 */
.phone {
  width: 100%;
  max-width: 270px;
  margin: 0 auto;
  padding: 9px;
  background: #23262b;
  border-radius: 32px;
  box-shadow: 0 18px 44px rgba(40, 32, 20, 0.16);
}

.phone img {
  display: block;
  width: 100%;
  border-radius: 24px;
}

/* ---------------- 通用区块 ---------------- */

.sec {
  padding: 64px 0;
  border-bottom: 1px solid var(--line-soft);
}

.sec:last-of-type {
  border-bottom: 0;
}

.sec-head {
  margin-bottom: 34px;
}

.sec-kicker {
  font-size: 12.5px;
  letter-spacing: 2px;
  color: var(--ink-3);
  text-transform: uppercase;
  margin: 0 0 8px;
}

h2 {
  font-family: var(--serif);
  font-size: 27px;
  font-weight: 600;
  letter-spacing: 1px;
  margin: 0 0 10px;
}

h3 {
  font-size: 17px;
  font-weight: 600;
  margin: 0 0 8px;
}

.sec-head p {
  color: var(--ink-3);
  margin: 0;
  max-width: 680px;
}

.prose p {
  color: var(--ink-2);
  margin: 0 0 16px;
  max-width: 780px;
}

.prose p:last-child {
  margin-bottom: 0;
}

/* 功能卡片 */
.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 18px;
}

.card {
  background: var(--card);
  border: 1px solid var(--line-soft);
  border-radius: 12px;
  padding: 24px 22px 22px;
}

.card h3 {
  display: flex;
  align-items: center;
  gap: 9px;
}

.card p {
  margin: 0;
  color: var(--ink-3);
  font-size: 14.5px;
  line-height: 1.7;
}

/* 序号印章 */
.num {
  flex: none;
  width: 22px;
  height: 22px;
  border-radius: 4px;
  background: var(--seal);
  color: #fff;
  font-size: 12px;
  font-family: var(--serif);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  letter-spacing: 0;
}

/* 截图展示 */
.shots {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 34px;
}

.shot {
  text-align: center;
}

.shot .phone {
  max-width: 232px;
}

.shot h3 {
  margin: 22px 0 4px;
  font-family: var(--serif);
  font-size: 17px;
  letter-spacing: 1px;
}

.shot p {
  margin: 0;
  color: var(--ink-3);
  font-size: 14px;
}

/* 适用人群 */
.who {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 12px;
}

.who div {
  background: var(--paper-2);
  border-radius: 10px;
  padding: 18px 14px;
  text-align: center;
  font-size: 14.5px;
  color: var(--ink-2);
  line-height: 1.5;
}

.who span {
  display: block;
  font-family: var(--serif);
  font-size: 15px;
  color: var(--ink);
  margin-bottom: 3px;
}

.who em {
  font-style: normal;
  font-size: 12.5px;
  color: var(--ink-3);
}

/* 信息条 */
.facts {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1px;
  background: var(--line-soft);
  border: 1px solid var(--line-soft);
  border-radius: 12px;
  overflow: hidden;
}

.facts div {
  background: #fff;
  padding: 20px 18px;
}

.facts dt {
  font-size: 12.5px;
  color: var(--ink-3);
  margin: 0 0 4px;
}

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

/* 下载 / 联系条 */
.cta {
  background: var(--ink);
  color: #fff;
  border-radius: 14px;
  padding: 38px 40px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 28px;
  flex-wrap: wrap;
}

.cta h2 {
  color: #fff;
  margin: 0 0 6px;
  font-size: 23px;
}

.cta p {
  margin: 0;
  color: rgba(255, 255, 255, 0.62);
  font-size: 14.5px;
}

/* 微信内不能直接下 APK，这行提示必须跟着下载按钮走，所以放在 cta 里 */
.cta .cta-note {
  margin-top: 10px;
  font-size: 12.5px;
  color: rgba(255, 255, 255, 0.42);
}

.cta .btn-solid {
  background: #fff;
  color: var(--ink);
  white-space: nowrap;
}

.cta .btn-ghost {
  background: transparent;
  border-color: rgba(255, 255, 255, 0.28);
  color: rgba(255, 255, 255, 0.9);
}

/* ---------------- 文档页（协议） ---------------- */

.doc {
  padding: 52px 0 72px;
}

.doc-head {
  border-bottom: 1px solid var(--line);
  padding-bottom: 22px;
  margin-bottom: 34px;
}

.doc-head h1 {
  font-size: 32px;
  margin: 0 0 8px;
}

.doc-meta {
  font-size: 13.5px;
  color: var(--ink-3);
  display: flex;
  gap: 18px;
  flex-wrap: wrap;
}

.doc-body {
  max-width: 820px;
}

.doc-body section {
  margin-bottom: 34px;
}

.doc-body h2 {
  font-size: 19px;
  margin: 0 0 12px;
  padding-left: 12px;
  border-left: 3px solid var(--seal);
  line-height: 1.4;
}

.doc-body p {
  margin: 0 0 12px;
  color: var(--ink-2);
  font-size: 15.5px;
}

.doc-body .item {
  margin: 0 0 14px;
  padding-left: 14px;
  border-left: 2px solid var(--line);
}

.doc-body .item b {
  display: block;
  font-size: 15.5px;
  color: var(--ink);
  margin-bottom: 3px;
  font-weight: 600;
}

.doc-body .item p {
  margin: 0;
}

.doc-body ul {
  margin: 0 0 12px;
  padding-left: 22px;
  color: var(--ink-2);
  font-size: 15.5px;
}

.doc-body ul li {
  margin-bottom: 6px;
}

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

.doc-tabs {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-bottom: 30px;
}

.doc-tabs a {
  padding: 7px 16px;
  border-radius: 999px;
  border: 1px solid var(--line);
  font-size: 14px;
  color: var(--ink-2);
  background: #fff;
}

.doc-tabs a.on {
  background: var(--ink);
  border-color: var(--ink);
  color: #fff;
}

/* ---------------- 页脚 ---------------- */

.ft {
  background: #16181c;
  color: rgba(255, 255, 255, 0.66);
  padding: 52px 0 28px;
  font-size: 14px;
}

.ft-grid {
  display: grid;
  grid-template-columns: 1.6fr 1fr 1fr 1.4fr;
  gap: 34px;
  padding-bottom: 32px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.ft-brand {
  display: flex;
  align-items: center;
  gap: 9px;
  font-family: var(--serif);
  font-size: 17px;
  color: #fff;
  letter-spacing: 1px;
  margin-bottom: 8px;
}

.ft-brand img {
  width: 26px;
  height: 26px;
  border-radius: 7px;
}

.ft h4 {
  color: #fff;
  font-size: 13.5px;
  font-weight: 500;
  margin: 0 0 12px;
  letter-spacing: 0.5px;
}

.ft a,
.ft p {
  display: block;
  margin: 0 0 9px;
  color: rgba(255, 255, 255, 0.62);
  line-height: 1.6;
}

.ft a:hover {
  color: #fff;
}

.ft-legal {
  padding-top: 22px;
  font-size: 13px;
  color: rgba(255, 255, 255, 0.42);
  line-height: 1.9;
}

.ft-legal a {
  color: rgba(255, 255, 255, 0.55);
  display: inline;
}

.ft-legal a:hover {
  color: #fff;
}

/* 待填项在页面上必须一眼看得出来 */
.todo {
  background: #ffe9c9;
  color: #8a4b00;
  border-radius: 3px;
  padding: 1px 5px;
  font-size: 0.94em;
}

/* ---------------- 响应式 ---------------- */

@media (max-width: 900px) {
  .hero-in {
    grid-template-columns: 1fr;
    gap: 40px;
  }

  h1 {
    font-size: 36px;
  }

  .grid-3,
  .shots {
    grid-template-columns: 1fr;
  }

  .shot {
    max-width: 300px;
    margin: 0 auto;
  }

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

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

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

@media (max-width: 640px) {
  .nav {
    display: none;
  }

  .hd-in {
    justify-content: center;
  }

  .hero {
    padding: 44px 0 52px;
  }

  h1 {
    font-size: 31px;
  }

  .sec {
    padding: 46px 0;
  }

  h2 {
    font-size: 23px;
  }

  .cta {
    padding: 28px 24px;
  }

  .ft-grid {
    grid-template-columns: 1fr;
    gap: 24px;
  }
}