/* 基础主题变量（自动适配深浅色） */
:root {
  --bg: #0b0c10;
  --surface: #12131a;
  --surface-2: #161823;
  --text: #e6e7eb;
  --muted: #aeb3c2;
  --brand: #0b5fff;
  --brand-2: #7dd3fc;
  --border: #232534;
  --card: #151827;
  --radius: 14px;
  --shadow: 0 10px 30px rgba(11,95,255,0.15);
  color-scheme: dark light;
}

@media (prefers-color-scheme: light) {
  :root {
    --bg: #f7f8fc;
    --surface: #ffffff;
    --surface-2: #f5f7ff;
    --text: #111826;
    --muted: #5b6270;
    --brand: #0b5fff;
    --brand-2: #0ea5e9;
    --border: #e7e9f3;
    --card: #ffffff;
    --shadow: 0 10px 30px rgba(11,95,255,0.12);
  }
}

* { box-sizing: border-box; }
html, body { height: 100%; scroll-behavior: smooth; }
body {
  margin: 0;
  font: 16px/1.6 system-ui, -apple-system, "PingFang SC", "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans CJK SC", "Microsoft YaHei", sans-serif;
  color: var(--text);
  background: linear-gradient(180deg, var(--bg), var(--surface-2) 60%, var(--bg) 100%);
}

/* 容器与常用组件 */
.container { width: min(1140px, 92vw); margin: 0 auto; }

.btn {
  display: inline-flex; align-items: center; justify-content: center;
  padding: 12px 18px; border-radius: 12px; border: 1px solid transparent;
  font-weight: 600; text-decoration: none; transition: all .2s ease;
  cursor: pointer; user-select: none;
}
.btn--primary { background: linear-gradient(90deg, var(--brand), var(--brand-2)); color: #fff; box-shadow: var(--shadow); }
.btn--primary:hover { transform: translateY(-1px); filter: saturate(1.1); }
.btn--ghost { border-color: var(--border); color: var(--text); background: transparent; }
.btn--ghost:hover { border-color: var(--brand); color: var(--brand); }

.section { padding: 80px 0; }
.section.alt { background: linear-gradient(180deg, var(--surface-2), transparent); }
.section__title { font-size: clamp(24px, 3.2vw, 36px); margin: 0 0 10px; letter-spacing: .2px; }
.section__desc { color: var(--muted); margin: 0 0 24px; }

/* Header */
.site-header {
  position: sticky; top: 0; z-index: 10;
  backdrop-filter: saturate(1.2) blur(8px);
  background: color-mix(in srgb, var(--surface), transparent 45%);
  border-bottom: 1px solid var(--border);
}
.site-header .brand {
  display: inline-flex; align-items: center; gap: 10px; font-weight: 700; color: var(--text); text-decoration: none; padding: 14px 0;
}
.nav { display: flex; gap: 16px; align-items: center; }
.nav ul { list-style: none; display: flex; gap: 18px; padding: 0; margin: 0; }
.nav a { color: var(--text); text-decoration: none; padding: 10px 8px; border-radius: 8px; }
.nav a:hover { color: var(--brand); background: color-mix(in srgb, var(--brand), transparent 90%); }

.site-header .brand, .nav { width: min(1140px, 92vw); margin: 0 auto; display: flex; justify-content: space-between; }

/* 移动端菜单 */
.hamburger { display: none; width: 40px; height: 40px; border: 1px solid var(--border); border-radius: 10px; background: transparent; }
.hamburger span { display: block; width: 22px; height: 2px; margin: 5px auto; background: var(--text); transition: .2s; }
@media (max-width: 860px) {
  .hamburger { display: inline-block; }
  .nav ul { position: absolute; right: 4%; top: 64px; width: 92%; flex-direction: column; background: var(--surface); border: 1px solid var(--border); border-radius: 14px; padding: 10px; display: none; }
  .nav ul.open { display: flex; }
}

/* Hero */
.hero { position: relative; overflow: hidden; padding: 120px 0 40px; }
.hero__bg {
  position: absolute; inset: -10% -10% auto -10%;
  height: 60%; z-index: -1;
  background:
    radial-gradient(1000px 400px at 20% 10%, color-mix(in srgb, var(--brand), transparent 70%), transparent 70%),
    radial-gradient(800px 350px at 80% 0%, color-mix(in srgb, var(--brand-2), transparent 70%), transparent 70%);
  filter: blur(30px) saturate(1.2);
}
.hero__inner { text-align: center; }
.hero h1 { font-size: clamp(28px, 5vw, 54px); margin: 0 0 12px; letter-spacing: .3px; }
.lead { color: var(--muted); font-size: clamp(16px, 2.4vw, 18px); margin: 0 auto 20px; width: min(860px, 92vw); }
.cta { display: inline-flex; gap: 12px; margin-top: 10px; }
.trust { list-style: none; display: flex; gap: 18px; padding: 0; margin: 24px 0 0; color: var(--muted); justify-content: center; flex-wrap: wrap; }
.hero__wave { display: block; width: 100%; height: 90px; }
.hero__wave path { fill: color-mix(in srgb, var(--brand), transparent 80%); }

/* 卡片与网格 */
.grid { display: grid; gap: 20px; }
.cards { grid-template-columns: repeat(4, 1fr); }
.cases { grid-template-columns: repeat(3, 1fr); }
@media (max-width: 1100px){ .cards{grid-template-columns: repeat(2,1fr);} .cases{grid-template-columns: repeat(2,1fr);} }
@media (max-width: 700px){ .cards,.cases{grid-template-columns: 1fr;} }

.card {
  background: var(--card); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 22px; box-shadow: var(--shadow); transition: transform .2s ease, border-color .2s;
}
.card:hover { transform: translateY(-4px); border-color: color-mix(in srgb, var(--brand), var(--border) 70%); }
.card .icon { width: 44px; height: 44px; display: grid; place-items: center; border-radius: 12px; background: color-mix(in srgb, var(--brand), transparent 85%); color: var(--brand); margin-bottom: 8px; }
.card h3 { margin: 8px 0; font-size: 18px; }
.list { padding-left: 18px; margin: 10px 0 0; color: var(--muted); }

.case {
  border: 1px solid var(--border); border-radius: var(--radius); overflow: hidden; background: var(--card); box-shadow: var(--shadow);
}
.case img { display: block; width: 100%; height: 220px; object-fit: cover; }
.case figcaption { padding: 16px; }
.case h3 { margin: 0 0 6px; font-size: 18px; }
.tag { display: inline-block; font-size: 12px; color: var(--brand); background: color-mix(in srgb, var(--brand), transparent 88%); border: 1px solid color-mix(in srgb, var(--brand), transparent 70%); padding: 4px 8px; border-radius: 999px; margin-right: 6px; }

/* 流程 Steps */
.steps { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; padding-left: 20px; }
.steps li { background: var(--card); border: 1px solid var(--border); border-radius: var(--radius); padding: 18px; box-shadow: var(--shadow); }
.steps h3 { margin: 0 0 6px; font-size: 18px; }
@media (max-width: 900px){ .steps{grid-template-columns: 1fr 1fr;} }
@media (max-width: 600px){ .steps{grid-template-columns: 1fr;} }

/* 技术栈 */
.tech { grid-template-columns: 1fr 1fr; }
.tech ul { margin: 0; padding-left: 18px; }
@media (max-width: 700px){ .tech{grid-template-columns: 1fr;} }

/* 关于 */
.about { display: grid; grid-template-columns: 1.5fr 1fr; gap: 24px; }
@media (max-width: 900px){ .about{grid-template-columns: 1fr;} }

/* 联系表单 */
.contact-form { background: var(--card); border: 1px solid var(--border); border-radius: var(--radius); padding: 18px; box-shadow: var(--shadow); }
.contact-form label { display: grid; gap: 6px; color: var(--muted); font-size: 14px; }
.contact-form input, .contact-form select, .contact-form textarea {
  width: 100%; padding: 12px 14px; border-radius: 10px; border: 1px solid var(--border);
  background: var(--surface); color: var(--text); outline: none; transition: border-color .2s;
}
.contact-form input:focus, .contact-form select:focus, .contact-form textarea:focus { border-color: var(--brand); }
.form-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 14px; margin-bottom: 12px; }
.form-actions { display: flex; gap: 12px; align-items: center; margin-top: 10px; }
.muted { color: var(--muted); }

@media (max-width: 700px){ .form-grid{grid-template-columns: 1fr;} }

/* Footer */
/* 页脚 */
.site-footer { border-top: 1px solid var(--border); padding: 30px 0; background: color-mix(in srgb, var(--surface), transparent 10%); }
.footer-inner { display: flex; align-items: center; justify-content: space-between; gap: 16px; }
.footer-inner nav a { color: var(--muted); text-decoration: none; margin-left: 12px; }
.footer-inner nav a:hover { color: var(--brand); }
.footer-brand small { color: var(--muted); display: block; margin-top: 6px; }

/* 备案信息样式 */
.备案信息 {
  text-align: center;
  margin-top: 20px;
  font-size: 14px;
  color: var(--muted);
}
.备案信息 small {
  color: var(--muted);
  font-size: 12px;
}
/* 备案信息 */
.beian {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 14px;
  margin: 12px auto 0;
  padding: 10px 0 24px;
  color: var(--muted);
}

.beian .icp {
  color: var(--muted);
  text-decoration: none;
  font-size: 12px;
}
.beian .icp:hover { color: var(--brand); }

.beian .psb {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 12px;
  user-select: none;
}
.beian .psb svg {
  width: 14px;
  height: 14px;
  opacity: .9;
}


/* 可访问性微调 */
:focus-visible { outline: 2px solid var(--brand); outline-offset: 3px; border-radius: 8px; }