/* uniskillAI 主题 v2 - 落地页 + 模态
   全部本地化, 无外网 CDN/字体/JS */

* { box-sizing: border-box; margin: 0; padding: 0; }
:root {
  --c-primary: #5e35b1;
  --c-accent:  #00bcd4;
  --c-bg:      #0f0f23;
  --c-bg-2:    #1a1a2e;
  --c-text:    #1a1a2e;
  --c-muted:   #5a5a7a;
  --c-line:    #e3e5ee;
  --c-card:    #ffffff;
  --shadow-md: 0 8px 24px rgba(15, 15, 35, .08);
  --shadow-lg: 0 30px 60px rgba(15, 15, 35, .12);
  --grad:      linear-gradient(135deg, var(--c-primary) 0%, var(--c-accent) 100%);
}

html, body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI",
               "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  color: var(--c-text);
  background: #f7f8fc;
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--c-primary); text-decoration: none; }
a:hover { text-decoration: underline; }

/* ============== 顶栏 ============== */
.topbar {
  position: sticky; top: 0; z-index: 50;
  background: rgba(15, 15, 35, .92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid rgba(255, 255, 255, .06);
  color: #fff;
  height: 60px;
  display: flex; align-items: center;
  padding: 0 32px;
}
.topbar .brand {
  display: flex; align-items: center; gap: 10px;
  font-size: 18px; font-weight: 600; letter-spacing: -.3px;
}
.topbar .brand .logo {
  width: 32px; height: 32px; border-radius: 8px;
  background: var(--grad);
  display: flex; align-items: center; justify-content: center;
  font-weight: 700; color: #fff; font-size: 17px;
}
.topbar .brand .ai { color: var(--c-accent); }
.topbar nav {
  margin-left: 40px; display: flex; gap: 28px;
  font-size: 14px; opacity: .9;
}
.topbar nav a { color: #fff; }
.topbar nav a:hover { opacity: 1; text-decoration: none; }
.topbar .right { margin-left: auto; display: flex; gap: 10px; align-items: center; font-size: 14px; }
.topbar .right .user {
  display: flex; align-items: center; gap: 8px;
  padding: 6px 12px; border-radius: 999px;
  background: rgba(255, 255, 255, .1);
  cursor: default;
}
.topbar .right .user .avatar {
  width: 26px; height: 26px; border-radius: 50%;
  background: var(--grad);
  display: flex; align-items: center; justify-content: center;
  font-size: 12px; font-weight: 700;
}
.topbar .right .user button {
  background: transparent; border: 0; color: rgba(255, 255, 255, .7);
  cursor: pointer; font-size: 12px; padding: 0 4px;
}
.topbar .right .user button:hover { color: #fff; }

.btn {
  display: inline-flex; align-items: center; justify-content: center;
  height: 36px; padding: 0 18px; border-radius: 8px;
  font-size: 14px; font-weight: 500; cursor: pointer;
  border: 1px solid transparent; transition: all .15s;
  text-decoration: none;
}
.btn-ghost {
  background: transparent; color: #fff;
  border-color: rgba(255, 255, 255, .25);
}
.btn-ghost:hover { background: rgba(255, 255, 255, .08); text-decoration: none; }
.btn-primary {
  background: var(--grad); color: #fff; border: 0;
  box-shadow: 0 4px 12px rgba(94, 53, 177, .25);
}
.btn-primary:hover { transform: translateY(-1px); box-shadow: 0 6px 16px rgba(94, 53, 177, .35); text-decoration: none; }
.btn-light {
  background: rgba(255, 255, 255, .14); color: #fff;
  border-color: rgba(255, 255, 255, .3);
}
.btn-light:hover { background: rgba(255, 255, 255, .22); text-decoration: none; }
.btn-outline {
  background: #fff; color: var(--c-primary);
  border-color: var(--c-primary);
}
.btn-outline:hover { background: var(--c-primary); color: #fff; text-decoration: none; }
.btn-lg { height: 48px; padding: 0 28px; font-size: 15px; }
.btn-sm { height: 30px; padding: 0 12px; font-size: 12px; }

/* ============== Hero ============== */
.hero {
  background:
    radial-gradient(circle at 15% 30%, rgba(94, 53, 177, .35), transparent 50%),
    radial-gradient(circle at 85% 70%, rgba(0, 188, 212, .25), transparent 50%),
    linear-gradient(180deg, #0f0f23 0%, #1a1a2e 100%);
  color: #fff;
  padding: 90px 32px 100px;
  text-align: center;
}
.hero .badge {
  display: inline-block;
  padding: 6px 14px; border-radius: 999px;
  background: rgba(255, 255, 255, .08);
  border: 1px solid rgba(255, 255, 255, .15);
  font-size: 12px; letter-spacing: 1px;
  margin-bottom: 24px; color: var(--c-accent);
}
.hero h1 {
  font-size: 52px; font-weight: 700; line-height: 1.15;
  letter-spacing: -1.2px; max-width: 820px; margin: 0 auto 20px;
}
.hero h1 .grad {
  background: linear-gradient(135deg, #b39dff 0%, #00bcd4 100%);
  -webkit-background-clip: text; background-clip: text;
  -webkit-text-fill-color: transparent; color: transparent;
}
.hero .sub {
  font-size: 18px; color: rgba(255, 255, 255, .7);
  max-width: 680px; margin: 0 auto 40px; line-height: 1.6;
}
.hero .ctas { display: flex; gap: 14px; justify-content: center; flex-wrap: wrap; }
.hero .stats {
  display: flex; gap: 48px; justify-content: center; flex-wrap: wrap;
  margin-top: 64px; padding-top: 40px;
  border-top: 1px solid rgba(255, 255, 255, .08);
}
.hero .stat .num {
  font-size: 32px; font-weight: 700; letter-spacing: -.5px;
  background: var(--grad); -webkit-background-clip: text; background-clip: text;
  -webkit-text-fill-color: transparent; color: transparent;
}
.hero .stat .label { font-size: 13px; color: rgba(255, 255, 255, .55); margin-top: 4px; }

/* ============== 通用 section ============== */
section { padding: 80px 32px; }
section .inner { max-width: 1200px; margin: 0 auto; }
section h2 {
  font-size: 36px; font-weight: 700; letter-spacing: -.8px;
  text-align: center; margin-bottom: 12px;
}
section .lead {
  font-size: 16px; color: var(--c-muted);
  text-align: center; max-width: 640px; margin: 0 auto 56px;
}

/* ============== 能力卡片 ============== */
.features { background: #fff; }
.features .grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 24px;
}
.features .card {
  padding: 32px 28px;
  background: var(--c-card);
  border: 1px solid var(--c-line);
  border-radius: 14px;
  transition: all .2s;
}
.features .card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-lg);
  border-color: transparent;
}
.features .icon {
  width: 48px; height: 48px; border-radius: 12px;
  background: linear-gradient(135deg, rgba(94, 53, 177, .12), rgba(0, 188, 212, .12));
  color: var(--c-primary);
  display: flex; align-items: center; justify-content: center;
  font-size: 22px; font-weight: 700;
  margin-bottom: 20px;
}
.features h3 { font-size: 18px; font-weight: 600; margin-bottom: 8px; }
.features p { font-size: 14px; color: var(--c-muted); line-height: 1.6; }

/* ============== Sandbox 入口卡片 ============== */
.demo { background: #f7f8fc; }
.demo .card {
  max-width: 880px; margin: 0 auto;
  background: var(--c-card);
  border: 1px solid var(--c-line);
  border-radius: 16px;
  padding: 48px;
  display: grid; grid-template-columns: 1fr 1fr; gap: 40px; align-items: center;
  box-shadow: var(--shadow-md);
}
.demo .card .left h3 {
  font-size: 24px; font-weight: 700; letter-spacing: -.5px; margin-bottom: 12px;
}
.demo .card .left p { color: var(--c-muted); margin-bottom: 20px; font-size: 14px; }
.demo .preview {
  background: #1a1a2e; border-radius: 10px; padding: 18px;
  font-family: "JetBrains Mono", Consolas, Monaco, monospace;
  font-size: 12px; color: #e0e0f0; line-height: 1.7;
  overflow: hidden;
}
.demo .preview .kw { color: #b39dff; }
.demo .preview .fn { color: #4dd0e1; }
.demo .preview .str { color: #81c784; }
.demo .preview .c { color: #6a6a8a; }

/* ============== 订购区 ============== */
.order {
  background: linear-gradient(135deg, #0f0f23 0%, #1a1a2e 100%);
  color: #fff; text-align: center;
}
.order h2 { color: #fff; }
.order .lead { color: rgba(255, 255, 255, .65); }
.order .plans {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 20px; max-width: 980px; margin: 0 auto 40px;
}
.order .plan {
  background: rgba(255, 255, 255, .04);
  border: 1px solid rgba(255, 255, 255, .1);
  border-radius: 14px; padding: 32px 24px;
  transition: all .2s; cursor: pointer;
  text-align: left;
}
.order .plan:hover {
  background: rgba(255, 255, 255, .08);
  transform: translateY(-3px);
  border-color: var(--c-accent);
}
.order .plan.featured {
  background: linear-gradient(135deg, rgba(94, 53, 177, .25), rgba(0, 188, 212, .15));
  border-color: var(--c-accent);
}
.order .plan h4 { font-size: 16px; font-weight: 600; margin-bottom: 6px; }
.order .plan .price {
  font-size: 32px; font-weight: 700; letter-spacing: -1px;
  margin: 14px 0 4px;
}
.order .plan .price small { font-size: 14px; font-weight: 400; opacity: .6; }
.order .plan ul { list-style: none; font-size: 13px; color: rgba(255, 255, 255, .7); margin: 18px 0; }
.order .plan li { padding: 5px 0; }
.order .plan li::before { content: "✓ "; color: var(--c-accent); margin-right: 4px; }

/* ============== Footer ============== */
footer {
  background: #fff; border-top: 1px solid var(--c-line);
  padding: 36px 32px; color: var(--c-muted); font-size: 13px;
}
footer .inner {
  max-width: 1200px; margin: 0 auto;
  display: flex; justify-content: space-between; align-items: center;
  flex-wrap: wrap; gap: 16px;
}
footer .links { display: flex; gap: 24px; flex-wrap: wrap; }
footer a { color: var(--c-muted); }
footer a:hover { color: var(--c-primary); }

/* ============== Modal ============== */
.modal-backdrop {
  position: fixed; inset: 0; z-index: 100;
  background: rgba(15, 15, 35, .55);
  backdrop-filter: blur(4px);
  display: flex; align-items: center; justify-content: center;
  padding: 24px;
  opacity: 0; pointer-events: none;
  transition: opacity .2s;
}
.modal-backdrop.open { opacity: 1; pointer-events: auto; }
.modal {
  background: #fff; border-radius: 16px;
  width: 100%; max-width: 420px;
  padding: 36px 32px;
  box-shadow: 0 40px 80px rgba(0, 0, 0, .3);
  transform: translateY(20px) scale(.96);
  transition: transform .2s;
}
.modal-backdrop.open .modal { transform: translateY(0) scale(1); }
.modal h2 {
  font-size: 22px; font-weight: 600; letter-spacing: -.3px; margin-bottom: 6px;
  text-align: left;
}
.modal .hint { color: var(--c-muted); font-size: 13px; margin-bottom: 22px; }
.modal .tabs {
  display: flex; gap: 0; margin-bottom: 24px;
  border-bottom: 1px solid var(--c-line);
}
.modal .tabs button {
  background: transparent; border: 0; padding: 10px 4px;
  margin: 0 16px 0 0; font-size: 14px; color: var(--c-muted);
  cursor: pointer; position: relative; font-weight: 500;
}
.modal .tabs button.active { color: var(--c-primary); }
.modal .tabs button.active::after {
  content: ""; position: absolute; left: 0; right: 0; bottom: -1px;
  height: 2px; background: var(--c-primary); border-radius: 2px 2px 0 0;
}
.modal label { display: block; font-size: 12px; color: var(--c-muted); font-weight: 500; margin: 14px 0 6px; }
.modal input, .modal select, .modal textarea {
  width: 100%; height: 42px; border-radius: 8px;
  border: 1px solid var(--c-line);
  padding: 0 12px; font-size: 14px; outline: none;
  background: #fff; color: var(--c-text);
  transition: border-color .15s, box-shadow .15s;
}
.modal input:focus, .modal select:focus, .modal textarea:focus {
  border-color: var(--c-primary);
  box-shadow: 0 0 0 3px rgba(94, 53, 177, .12);
}
.modal textarea { height: auto; padding: 10px 12px; resize: vertical; }
.modal .row { display: flex; gap: 12px; }
.modal .row > * { flex: 1; }
.modal .submit { width: 100%; margin-top: 24px; }
.modal .close {
  position: absolute; top: 14px; right: 14px;
  width: 32px; height: 32px; border-radius: 8px;
  background: transparent; border: 0; cursor: pointer;
  color: var(--c-muted); font-size: 18px;
  display: flex; align-items: center; justify-content: center;
}
.modal .close:hover { background: #f4f5fa; color: var(--c-text); }
.modal .err {
  background: #fdecea; color: #b71c1c;
  padding: 10px 12px; border-radius: 8px;
  font-size: 13px; margin: 8px 0;
  display: none;
}
.modal .err.show { display: block; }
.modal .ok {
  background: #e8f5e9; color: #1b5e20;
  padding: 10px 12px; border-radius: 8px;
  font-size: 13px; margin: 8px 0;
  display: none;
}
.modal .ok.show { display: block; }
.modal .meta { font-size: 12px; color: var(--c-muted); margin-top: 16px; text-align: center; }
.modal .meta a { color: var(--c-primary); }

.modal { position: relative; }

.modal.order-modal { max-width: 480px; }
.modal.order-modal .summary {
  background: #fafbfd; border: 1px solid var(--c-line);
  border-radius: 10px; padding: 16px; margin-top: 16px;
  font-size: 14px;
}
.modal.order-modal .summary .row-line {
  display: flex; justify-content: space-between; padding: 4px 0;
}
.modal.order-modal .summary .total {
  border-top: 1px solid var(--c-line); margin-top: 8px; padding-top: 10px;
  font-weight: 600; font-size: 15px;
}

/* ============== 响应式 ============== */
@media (max-width: 768px) {
  .topbar nav { display: none; }
  .hero { padding: 60px 20px 70px; }
  .hero h1 { font-size: 32px; }
  .hero .sub { font-size: 15px; }
  .hero .stats { gap: 28px; }
  .hero .stat .num { font-size: 24px; }
  section { padding: 50px 20px; }
  section h2 { font-size: 26px; }
  .demo .card { grid-template-columns: 1fr; padding: 28px; }
  footer .inner { flex-direction: column; align-items: flex-start; }
}