/* ==========================================================================
   深圳大树下网络科技有限公司 官网样式
   纯手写 CSS，无框架依赖。配色沿用旧站：深色导航 + 红色强调。
   ========================================================================== */

:root {
  --navy: #1a1f2a;
  --navy-dark: #0d121b;
  --navy-soft: #252b38;
  --red: #d22e3e;
  --red-dark: #ba1f2e;
  --text: #2b3242;
  --muted: #737b8a;
  --line: #e6e8ec;
  --bg: #ffffff;
  --bg-alt: #f5f6f8;
  --footer-text: #9aa3b2;
  --container: 1200px;
  --radius: 6px;
  --shadow: 0 8px 24px rgba(26, 31, 42, 0.08);
}

* { box-sizing: border-box; }

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

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  font-size: 15px;
  line-height: 1.7;
  color: var(--text);
  background: var(--bg);
}

a { color: var(--text); text-decoration: none; transition: color .3s ease, background-color .3s ease, border-color .3s ease; }
a:hover { color: var(--red); }

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

h1, h2, h3, h4 { margin: 0; line-height: 1.3; font-weight: 600; }
p { margin: 0 0 1em; }
ul { margin: 0; padding: 0; list-style: none; }

.container { max-width: var(--container); margin: 0 auto; padding: 0 20px; }

.visually-hidden {
  position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px;
  overflow: hidden; clip: rect(0, 0, 0, 0); white-space: nowrap; border: 0;
}

/* --------------------------------------------------------------------------
   按钮
   -------------------------------------------------------------------------- */
.btn {
  display: inline-block;
  padding: 11px 28px;
  border-radius: var(--radius);
  font-size: 15px;
  font-weight: 500;
  line-height: 1.4;
  border: 1px solid transparent;
  cursor: pointer;
  text-align: center;
  white-space: nowrap;
  transition: all .3s ease;
}
.btn-primary { background: var(--red); border-color: var(--red); color: #fff; }
.btn-primary:hover { background: var(--red-dark); border-color: var(--red-dark); color: #fff; }
.btn-outline { background: transparent; border-color: rgba(255, 255, 255, .7); color: #fff; }
.btn-outline:hover { background: #fff; color: var(--navy); border-color: #fff; }
.btn-dark { background: var(--navy); border-color: var(--navy); color: #fff; }
.btn-dark:hover { background: var(--navy-dark); color: #fff; }
.btn-lg { padding: 14px 36px; font-size: 16px; }
.btn-block { display: block; width: 100%; }

/* --------------------------------------------------------------------------
   头部导航
   -------------------------------------------------------------------------- */
.site-header {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 50;
  background: rgba(26, 31, 42, .95);
  color: #fff;
  transition: box-shadow .3s ease;
}
.site-header.is-scrolled { box-shadow: 0 2px 12px rgba(0, 0, 0, .25); }
.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 70px;
}
.logo { display: inline-flex; align-items: center; }
.logo img { height: 40px; width: auto; display: block; }
.footer-logo { height: 36px; width: auto; margin-bottom: 16px; }

.site-nav { display: flex; gap: 4px; }
.site-nav a {
  display: block;
  padding: 8px 16px;
  color: #fff;
  border-radius: 3px;
  font-size: 15px;
}
.site-nav a:hover, .site-nav a.is-active { background: var(--red-dark); color: #fff; }

.nav-toggle {
  display: none;
  background: transparent;
  border: 1px solid rgba(255, 255, 255, .3);
  color: #fff;
  border-radius: 4px;
  width: 42px; height: 38px;
  cursor: pointer;
  align-items: center; justify-content: center;
}
.nav-toggle svg { width: 22px; height: 22px; }

/* --------------------------------------------------------------------------
   Hero 与页头横幅
   -------------------------------------------------------------------------- */
.hero {
  position: relative;
  min-height: 680px;
  display: flex;
  align-items: center;
  color: #fff;
  background-size: cover;
  background-position: center;
  background-repeat: no-repeat;
  text-align: center;
  padding: 130px 0 80px;
}
.hero::before {
  content: "";
  position: absolute; inset: 0;
  background: linear-gradient(180deg, rgba(13, 18, 27, .55) 0%, rgba(13, 18, 27, .45) 60%, rgba(13, 18, 27, .7) 100%);
}
.hero .container { position: relative; }
.hero h1 {
  font-size: 44px;
  font-weight: 500;
  margin-bottom: 14px;
  letter-spacing: 1px;
}
.hero .hero-sub {
  font-size: 22px;
  font-weight: 300;
  color: rgba(255, 255, 255, .92);
  margin-bottom: 32px;
}
.hero .hero-actions { display: flex; gap: 14px; justify-content: center; flex-wrap: wrap; }

.page-banner {
  position: relative;
  min-height: 420px;
  display: flex;
  align-items: center;
  color: #fff;
  background-size: cover;
  background-position: center;
  background-attachment: fixed;
  padding: 130px 0 60px;
}
.page-banner::before {
  content: "";
  position: absolute; inset: 0;
  background: rgba(13, 18, 27, .55);
}
.page-banner .container { position: relative; }
.page-banner h1 { font-size: 42px; font-weight: 300; margin-bottom: 10px; }
.page-banner p { font-size: 18px; color: rgba(255, 255, 255, .9); margin: 0; max-width: 720px; }

/* --------------------------------------------------------------------------
   通用区块
   -------------------------------------------------------------------------- */
.section { padding: 80px 0; }
.section-alt { background: var(--bg-alt); }
.section-dark { background: var(--navy); color: #fff; }
.section-dark .section-title p { color: rgba(255, 255, 255, .7); }

.section-title { text-align: center; margin-bottom: 48px; }
.section-title h2 { font-size: 32px; font-weight: 500; margin-bottom: 12px; }
.section-title p { color: var(--muted); font-size: 15px; max-width: 760px; margin: 0 auto; }
.section-title.is-left { text-align: left; }
.section-title.is-left p { margin: 0; }

.grid { display: grid; gap: 24px; }
.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }

.card {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 32px 28px;
  transition: transform .3s ease, box-shadow .3s ease, border-color .3s ease;
}
.card:hover { transform: translateY(-4px); box-shadow: var(--shadow); border-color: transparent; }
.card h3 { font-size: 19px; margin-bottom: 10px; }
.card p { color: var(--muted); margin: 0; font-size: 14.5px; }
.card .card-link { display: inline-block; margin-top: 16px; color: var(--red); font-size: 14px; }

.section-dark .card { background: var(--navy-soft); border-color: rgba(255, 255, 255, .08); }
.section-dark .card h3 { color: #fff; }
.section-dark .card p { color: rgba(255, 255, 255, .7); }
.section-dark .card:hover { background: var(--red); border-color: var(--red); }
.section-dark .card:hover p { color: rgba(255, 255, 255, .92); }
.section-dark .card:hover .icon { background: rgba(255, 255, 255, .2); color: #fff; }
/* 红底 hover 时链接改白字，否则红字红底看不见 */
.section-dark .card:hover .card-link,
.section-dark .card:hover .card-link:hover { color: #fff; text-decoration: underline; text-underline-offset: 3px; }

.icon {
  width: 52px; height: 52px;
  border-radius: 12px;
  background: rgba(210, 46, 62, .1);
  color: var(--red);
  display: inline-flex; align-items: center; justify-content: center;
  margin-bottom: 18px;
  transition: all .3s ease;
}
.icon svg { width: 26px; height: 26px; }
.section-dark .icon { background: rgba(210, 46, 62, .25); color: #ff8a94; }

/* 步骤流程 */
.steps { display: grid; grid-template-columns: repeat(5, 1fr); gap: 16px; counter-reset: step; }
.steps-3 { grid-template-columns: repeat(3, 1fr); }
.step {
  position: relative;
  padding: 28px 20px 24px;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  text-align: center;
}
.step-num {
  width: 44px; height: 44px;
  border-radius: 50%;
  background: var(--red);
  color: #fff;
  font-size: 18px;
  font-weight: 600;
  display: inline-flex; align-items: center; justify-content: center;
  margin-bottom: 14px;
}
.step h3 { font-size: 17px; margin-bottom: 8px; }
.step p { color: var(--muted); font-size: 14px; margin: 0; }

/* 定价 */
.pricing { display: grid; grid-template-columns: repeat(2, 1fr); gap: 28px; max-width: 900px; margin: 0 auto; }
.price-card {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 36px 32px;
  position: relative;
  transition: transform .3s ease, box-shadow .3s ease;
}
.price-card:hover { transform: translateY(-4px); box-shadow: var(--shadow); }
.price-card.is-featured { border: 2px solid var(--red); }
.price-badge {
  position: absolute; top: -13px; left: 32px;
  background: var(--red); color: #fff;
  font-size: 12px; padding: 3px 12px; border-radius: 20px;
}
.price-card h3 { font-size: 20px; margin-bottom: 6px; }
.price-card .price-desc { color: var(--muted); font-size: 14px; margin-bottom: 18px; }
.price { display: flex; align-items: baseline; gap: 4px; margin-bottom: 20px; }
.price .amount { font-size: 42px; font-weight: 700; color: var(--red); line-height: 1; }
.price .unit { color: var(--muted); font-size: 15px; }
.price-card ul li {
  padding: 8px 0 8px 26px;
  border-top: 1px dashed var(--line);
  position: relative;
  font-size: 14.5px;
}
.price-card ul li::before {
  content: "";
  position: absolute; left: 2px; top: 14px;
  width: 14px; height: 14px;
  border-radius: 50%;
  background: var(--red);
  -webkit-mask: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='white' stroke-width='3' stroke-linecap='round' stroke-linejoin='round'><polyline points='20 6 9 17 4 12'/></svg>") center/contain no-repeat;
          mask: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='white' stroke-width='3' stroke-linecap='round' stroke-linejoin='round'><polyline points='20 6 9 17 4 12'/></svg>") center/contain no-repeat;
}
.price-card .btn { margin-top: 24px; }
.pricing-note {
  max-width: 900px; margin: 28px auto 0;
  padding: 20px 24px;
  background: var(--bg-alt);
  border-left: 4px solid var(--red);
  border-radius: 0 var(--radius) var(--radius) 0;
  font-size: 14.5px;
  color: var(--text);
}
.pricing-note strong { color: var(--red); }

/* 信息表格 */
.info-table { width: 100%; border-collapse: collapse; background: #fff; border: 1px solid var(--line); }
.info-table th, .info-table td { padding: 14px 18px; border-bottom: 1px solid var(--line); text-align: left; vertical-align: top; font-size: 14.5px; }
.info-table th { width: 180px; background: var(--bg-alt); font-weight: 500; color: var(--muted); white-space: nowrap; }
.info-table tr:last-child th, .info-table tr:last-child td { border-bottom: 0; }

/* 特性列表 */
.feature-list li { display: flex; gap: 14px; padding: 14px 0; border-bottom: 1px solid var(--line); }
.feature-list li:last-child { border-bottom: 0; }
.feature-list .icon { width: 42px; height: 42px; margin: 0; flex-shrink: 0; border-radius: 10px; }
.feature-list .icon svg { width: 22px; height: 22px; }
.feature-list h4 { font-size: 16px; margin-bottom: 4px; }
.feature-list p { color: var(--muted); font-size: 14px; margin: 0; }

/* 两栏图文 */
.split { display: grid; grid-template-columns: 1fr 1fr; gap: 56px; align-items: center; }
.split h2 { font-size: 30px; font-weight: 500; margin-bottom: 16px; }
.split .lead { color: var(--muted); font-size: 15.5px; }

/* CTA 横幅 */
.cta {
  background: var(--navy);
  color: #fff;
  padding: 56px 0;
}
.cta .container {
  display: flex; align-items: center; justify-content: space-between; gap: 24px; flex-wrap: wrap;
}
.cta h2 { font-size: 26px; font-weight: 400; margin-bottom: 6px; }
.cta p { color: rgba(255, 255, 255, .7); margin: 0; }

/* 表单 */
.form-card {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 40px;
  max-width: 820px;
  margin: 0 auto;
}
.form-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 18px 24px; }
.form-field { display: flex; flex-direction: column; gap: 6px; }
.form-field.is-full { grid-column: 1 / -1; }
.form-field label { font-size: 14px; font-weight: 500; }
.form-field label .req { color: var(--red); margin-left: 2px; }
.form-field input, .form-field select, .form-field textarea {
  font: inherit;
  font-size: 14.5px;
  padding: 10px 12px;
  border: 1px solid #cfd3da;
  border-radius: 4px;
  background: #fff;
  color: var(--text);
  transition: border-color .2s ease, box-shadow .2s ease;
  width: 100%;
}
.form-field input:focus, .form-field select:focus, .form-field textarea:focus {
  outline: none;
  border-color: var(--red);
  box-shadow: 0 0 0 3px rgba(210, 46, 62, .12);
}
.form-field textarea { min-height: 120px; resize: vertical; }
.check-group { display: flex; gap: 20px; flex-wrap: wrap; padding-top: 4px; }
.check-group label { display: inline-flex; align-items: center; gap: 6px; font-weight: 400; cursor: pointer; }
.check-group input { width: auto; accent-color: var(--red); }
.form-actions { grid-column: 1 / -1; display: flex; align-items: center; gap: 16px; flex-wrap: wrap; margin-top: 8px; }
.form-hint { font-size: 13px; color: var(--muted); margin: 0; }
.form-msg { grid-column: 1 / -1; font-size: 14px; color: var(--red); margin: 0; min-height: 1.4em; }

/* 联系卡片 */
.contact-card {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 34px 24px;
  text-align: center;
  transition: all .3s ease;
}
.contact-card:hover { background: var(--navy); border-color: var(--navy); color: #fff; }
.contact-card:hover .icon { background: rgba(255, 255, 255, .15); color: #fff; }
.contact-card:hover p, .contact-card:hover a { color: rgba(255, 255, 255, .85); }
.contact-card h3 { font-size: 16px; margin-bottom: 8px; color: inherit; }
.contact-card p { margin: 0; font-size: 15px; color: var(--muted); word-break: break-all; }
.contact-card .icon { margin: 0 auto 16px; }

/* 硬件产品展示 */
.device-stage {
  background: linear-gradient(135deg, var(--navy) 0%, #2c3444 100%);
  border-radius: 12px;
  padding: 48px 40px;
  color: #fff;
  display: flex; align-items: center; justify-content: center;
}
.device-wrap { width: 100%; max-width: 340px; }
.device {
  width: 100%;
  aspect-ratio: 9 / 16;
  background: #0b0e14;
  border: 10px solid #2f3746;
  border-radius: 14px;
  position: relative;
  overflow: hidden;
  box-shadow: 0 30px 60px rgba(0, 0, 0, .45);
}
.device-screen {
  position: absolute; inset: 0;
  overflow: hidden;
  background: #1a1f2a;
}
.ds-slide {
  position: absolute; inset: 0;
  padding: 24px;
  display: flex; flex-direction: column; justify-content: flex-end;
  opacity: 0;
  transition: opacity .7s ease;
}
.ds-slide.is-active { opacity: 1; }
.ds-theme-red   { background: linear-gradient(160deg, #d22e3e 0%, #7a1c28 45%, #1a1f2a 100%); }
.ds-theme-blue  { background: linear-gradient(160deg, #2f6fd6 0%, #1d3d7a 45%, #1a1f2a 100%); }
.ds-theme-green { background: linear-gradient(160deg, #1f9d55 0%, #145c36 45%, #1a1f2a 100%); }
.ds-theme-navy  { background: linear-gradient(160deg, #4a5670 0%, #2a3244 45%, #0d121b 100%); }
.ds-slide .ds-tag { font-size: 11px; letter-spacing: 3px; opacity: .7; margin-bottom: 8px; }
.ds-slide .ds-title { font-size: 24px; font-weight: 600; line-height: 1.25; margin-bottom: 10px; }
.ds-slide .ds-desc { font-size: 12px; opacity: .8; margin: 0; }
.ds-slide .ds-tag, .ds-slide .ds-title, .ds-slide .ds-desc {
  transform: translateY(12px);
  transition: transform .7s ease;
}
.ds-slide.is-active .ds-tag, .ds-slide.is-active .ds-title, .ds-slide.is-active .ds-desc { transform: translateY(0); }
.ds-bars {
  position: absolute; top: 24px; left: 24px; right: 24px;
  display: flex; gap: 6px;
  z-index: 2;
}
.ds-bars span {
  position: relative;
  height: 4px; flex: 1;
  background: rgba(255, 255, 255, .3);
  border-radius: 2px;
  overflow: hidden;
}
.ds-bars span::after {
  content: "";
  position: absolute; inset: 0;
  background: #fff;
  transform: scaleX(0);
  transform-origin: left center;
}
.ds-bars span.is-done::after { transform: scaleX(1); }
.ds-bars span.is-active::after { animation: ds-progress var(--ds-interval, 3.5s) linear forwards; }
@keyframes ds-progress { from { transform: scaleX(0); } to { transform: scaleX(1); } }
@media (prefers-reduced-motion: reduce) {
  .ds-slide, .ds-slide .ds-tag, .ds-slide .ds-title, .ds-slide .ds-desc { transition: none; }
  .ds-bars span.is-active::after { animation: none; transform: scaleX(1); }
}
.device-stand { width: 60%; height: 12px; background: #2f3746; border-radius: 0 0 6px 6px; margin: 0 auto; }

.spec-tabs { display: flex; gap: 8px; flex-wrap: wrap; margin-bottom: 16px; }
.spec-tabs button {
  font: inherit;
  font-size: 13px;
  padding: 6px 14px;
  border: 1px solid var(--line);
  border-radius: 20px;
  background: #fff;
  color: var(--muted);
  cursor: pointer;
  transition: all .25s ease;
}
.spec-tabs button:hover { border-color: var(--navy); color: var(--navy); }
.spec-tabs button.is-active { background: var(--navy); border-color: var(--navy); color: #fff; }
.spec-tabs button:focus-visible { outline: 2px solid var(--red); outline-offset: 2px; }
.tab-panel { display: none; }
.tab-panel.is-active { display: block; animation: tab-in .35s ease; }
@keyframes tab-in { from { opacity: 0; transform: translateY(6px); } to { opacity: 1; transform: none; } }

.scene-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; }
.scene {
  background: #fff; border: 1px solid var(--line); border-radius: var(--radius);
  padding: 26px 20px; text-align: center;
}
.scene .icon { margin: 0 auto 14px; }
.scene h3 { font-size: 16px; margin-bottom: 6px; }
.scene p { color: var(--muted); font-size: 13.5px; margin: 0; }

.note-box {
  margin-top: 28px;
  padding: 16px 20px;
  background: #fff8f8;
  border: 1px solid rgba(210, 46, 62, .25);
  border-radius: var(--radius);
  font-size: 13.5px;
  color: var(--muted);
}

/* 标签 */
.tag-list { display: flex; flex-wrap: wrap; gap: 10px; }
.tag-list span {
  padding: 8px 16px;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 20px;
  font-size: 14px;
}

/* --------------------------------------------------------------------------
   页脚
   -------------------------------------------------------------------------- */
.site-footer { background: var(--navy); color: var(--footer-text); font-size: 14px; padding-top: 60px; }
.site-footer a { color: var(--footer-text); }
.site-footer a:hover { color: #fff; }
.footer-grid { display: grid; grid-template-columns: 1.4fr 0.8fr 1.2fr; gap: 48px; padding-bottom: 50px; }
.site-footer h2 { font-size: 16px; color: #fff; font-weight: 500; margin-bottom: 18px; }
.site-footer p { margin: 0 0 8px; line-height: 1.8; }
.footer-nav li { margin-bottom: 8px; }
.footer-bottom {
  background: var(--navy-dark);
  padding: 22px 0;
  font-size: 12.5px;
  text-align: center;
  line-height: 2;
}
.footer-bottom .beian { display: inline-flex; flex-wrap: wrap; justify-content: center; gap: 6px 18px; }
.footer-bottom .legal-links { display: flex; flex-wrap: wrap; justify-content: center; gap: 6px 18px; }

/* 协议 / 政策正文 */
.prose { max-width: 860px; margin: 0 auto; font-size: 15px; line-height: 1.9; }
.prose .prose-meta { color: var(--muted); font-size: 13.5px; margin-bottom: 28px; }
.prose h2 { font-size: 20px; font-weight: 500; margin: 36px 0 12px; }
.prose p { margin: 0 0 12px; }
.prose ol, .prose ul { margin: 0 0 12px; padding-left: 1.6em; list-style: decimal; }
.prose ul { list-style: disc; }
.prose li { margin-bottom: 6px; }

/* 返回顶部 */
.back-top {
  position: fixed;
  right: 16px; bottom: -80px;
  width: 42px; height: 42px;
  background: var(--red);
  color: #fff;
  border: 0;
  border-radius: 4px;
  cursor: pointer;
  display: inline-flex; align-items: center; justify-content: center;
  transition: bottom .3s ease, background-color .3s ease;
  z-index: 40;
}
.back-top.is-visible { bottom: 16px; }
.back-top:hover { background: var(--red-dark); }
.back-top svg { width: 20px; height: 20px; }

/* --------------------------------------------------------------------------
   响应式
   -------------------------------------------------------------------------- */
@media (max-width: 1100px) {
  .steps { grid-template-columns: repeat(3, 1fr); }
  .scene-grid { grid-template-columns: repeat(2, 1fr); }
  .grid-4 { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 960px) {
  .hero { min-height: 560px; }
  .hero h1 { font-size: 36px; }
  .hero .hero-sub { font-size: 18px; }
  .page-banner { min-height: 340px; background-attachment: scroll; }
  .page-banner h1 { font-size: 34px; }
  .split { grid-template-columns: 1fr; gap: 36px; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .grid-3 { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 768px) {
  .site-header .container { height: 60px; }
  .logo img { height: 34px; }
  .nav-toggle { display: inline-flex; }
  .site-nav {
    position: absolute; top: 60px; left: 0; right: 0;
    flex-direction: column;
    background: var(--navy);
    padding: 8px 12px 14px;
    display: none;
    border-top: 1px solid rgba(255, 255, 255, .08);
  }
  .site-nav.is-open { display: flex; }
  .site-nav a { padding: 12px 14px; }
  .hero { padding-top: 100px; min-height: 480px; }
  .hero h1 { font-size: 28px; }
  .hero .hero-sub { font-size: 16px; }
  .page-banner { padding-top: 100px; min-height: 280px; }
  .page-banner h1 { font-size: 28px; }
  .page-banner p { font-size: 15px; }
  .section { padding: 56px 0; }
  .section-title h2 { font-size: 26px; }
  .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
  .steps, .steps-3 { grid-template-columns: 1fr 1fr; }
  .pricing { grid-template-columns: 1fr; }
  .form-grid { grid-template-columns: 1fr; }
  .form-card { padding: 28px 20px; }
  .info-table th { width: 110px; }
  .cta .container { flex-direction: column; text-align: center; }
  .device-stage { padding: 32px 20px; }
  .footer-grid { grid-template-columns: 1fr; gap: 28px; }
  .scene-grid { grid-template-columns: 1fr; }
}

@media (max-width: 480px) {
  .steps, .steps-3 { grid-template-columns: 1fr; }
  .hero .hero-actions .btn { width: 100%; }
}

/* 渐变页头（无图片的页面使用） */
.page-banner.is-gradient {
  background:
    radial-gradient(900px 420px at 15% -10%, rgba(210, 46, 62, .45), transparent 65%),
    radial-gradient(700px 360px at 90% 110%, rgba(210, 46, 62, .25), transparent 60%),
    linear-gradient(135deg, #1a1f2a 0%, #232a38 100%);
  background-attachment: scroll;
}
.page-banner.is-gradient::before { display: none; }