/* ============================================================
   四维AI · aiiii.com.cn — 全站共享样式
   品牌色：靛蓝 #4f46e5 → 青 #0ea5e9
   纯静态站点，无外部依赖
   ============================================================ */

:root {
  --bg: #f6f7fb;
  --bg2: #ffffff;
  --ink: #1a1d29;
  --muted: #6b7280;
  --rule: #e5e7eb;
  --accent: #4f46e5;
  --accent-dark: #3730a3;
  --accent2: #0ea5e9;
  --green: #16a34a;
  --green-bg: #f0fdf4;
  --green-rule: #bbf7d0;
  --red: #dc2626;
  --red-bg: #fef2f2;
  --red-rule: #fecaca;
  --amber: #d97706;
  --amber-bg: #fffbeb;
  --amber-rule: #fde68a;
  --radius: 12px;
  --shadow: 0 8px 24px rgba(15, 23, 42, 0.06);
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }

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

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

.container { max-width: 1080px; margin: 0 auto; padding: 0 24px; }

/* ---------- 顶部导航 ---------- */
.nav {
  position: sticky; top: 0; z-index: 100;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--rule);
}
.nav-inner { display: flex; align-items: center; justify-content: space-between; height: 60px; }
.brand { display: flex; align-items: center; gap: 10px; font-weight: 700; font-size: 1.1rem; color: var(--ink); }
.brand:hover { text-decoration: none; }
.brand .logo {
  width: 34px; height: 34px; border-radius: 9px;
  background: linear-gradient(135deg, var(--accent), var(--accent2));
  color: #fff; display: flex; align-items: center; justify-content: center;
  font-size: 0.85rem; font-weight: 700;
}
.nav-links { display: flex; gap: 4px; align-items: center; }
.nav-links a {
  color: var(--ink); font-size: 0.92rem; padding: 8px 12px; border-radius: 8px;
}
.nav-links a:hover { background: #eef2ff; color: var(--accent); text-decoration: none; }
.nav-links a.active { background: var(--accent); color: #fff; }
.nav-cta {
  background: linear-gradient(135deg, var(--accent), var(--accent2));
  color: #fff !important; font-weight: 600;
}
.nav-toggle { display: none; background: none; border: none; font-size: 1.4rem; cursor: pointer; color: var(--ink); }

@media (max-width: 860px) {
  .nav-toggle { display: block; }
  .nav-links {
    display: none; position: absolute; top: 60px; left: 0; right: 0;
    background: #fff; border-bottom: 1px solid var(--rule);
    flex-direction: column; padding: 12px 24px 20px; gap: 2px;
  }
  .nav-links.open { display: flex; }
  .nav-links a { display: block; padding: 10px 12px; }
}

/* ---------- Hero ---------- */
.hero {
  background: linear-gradient(135deg, #0f172a 0%, #4f46e5 55%, #0ea5e9 100%);
  color: #fff; padding: 72px 24px 64px; text-align: center;
}
.hero h1 { font-size: 2.2rem; font-weight: 700; margin-bottom: 14px; letter-spacing: -0.02em; }
.hero .subtitle { font-size: 1.08rem; opacity: 0.93; max-width: 720px; margin: 0 auto 26px; }
.hero .subtitle b { color: #fff; }
.hero-actions { display: flex; gap: 14px; justify-content: center; flex-wrap: wrap; }
.btn {
  display: inline-block; padding: 11px 24px; border-radius: 10px;
  font-weight: 600; font-size: 0.95rem; border: none; cursor: pointer;
  transition: transform 0.12s ease, box-shadow 0.12s ease;
}
.btn:hover { transform: translateY(-1px); text-decoration: none; }
.btn-light { background: #fff; color: var(--accent-dark); box-shadow: 0 4px 14px rgba(0,0,0,0.18); }
.btn-ghost { background: rgba(255,255,255,0.14); color: #fff; border: 1px solid rgba(255,255,255,0.4); }
.btn-primary { background: linear-gradient(135deg, var(--accent), var(--accent2)); color: #fff; box-shadow: var(--shadow); }
.btn-outline { background: #fff; color: var(--accent); border: 1.5px solid #c7d2fe; }
.btn-lg { padding: 13px 30px; font-size: 1.02rem; }

/* ---------- Section ---------- */
section { padding: 48px 0 12px; }
.h2 { font-size: 1.5rem; font-weight: 700; margin-bottom: 8px; }
.h2-sub { color: var(--muted); margin-bottom: 26px; }
.h3 { font-size: 1.15rem; font-weight: 700; margin: 26px 0 12px; }
.section-head { text-align: center; margin-bottom: 30px; }
.section-head .h2 { margin-bottom: 8px; }

/* ---------- 卡片网格 ---------- */
.grid { display: grid; gap: 18px; }
.grid-4 { grid-template-columns: repeat(4, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-2 { grid-template-columns: repeat(2, 1fr); }
@media (max-width: 960px) { .grid-4 { grid-template-columns: repeat(2, 1fr); } .grid-3 { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 620px) { .grid-4, .grid-3, .grid-2 { grid-template-columns: 1fr; } }

.card {
  background: var(--bg2); border: 1px solid var(--rule); border-radius: var(--radius);
  padding: 20px; transition: box-shadow 0.15s ease, transform 0.15s ease;
}
.card:hover { box-shadow: var(--shadow); transform: translateY(-2px); }
.card .icon {
  width: 46px; height: 46px; border-radius: 12px;
  background: linear-gradient(135deg, #eef2ff, #ecfeff);
  color: var(--accent); font-size: 1.25rem;
  display: flex; align-items: center; justify-content: center; margin-bottom: 12px;
}
.card h3 { font-size: 1.05rem; margin-bottom: 6px; }
.card p { color: var(--muted); font-size: 0.9rem; }

/* ---------- 工具卡片 ---------- */
.tool-card { cursor: pointer; position: relative; }
.tool-card .tc-head { display: flex; align-items: center; gap: 12px; margin-bottom: 10px; }
.tool-avatar {
  width: 42px; height: 42px; border-radius: 10px; flex-shrink: 0;
  background: linear-gradient(135deg, var(--accent), var(--accent2));
  color: #fff; display: flex; align-items: center; justify-content: center;
  font-weight: 700; font-size: 1rem;
}
.tool-card .tc-head h3 { font-size: 1rem; margin-bottom: 2px; }
.tool-card .tc-head .sub { font-size: 0.78rem; color: var(--muted); }
.tool-card .brief { color: #374151; font-size: 0.88rem; margin-bottom: 10px; min-height: 48px; }
.tags { display: flex; flex-wrap: wrap; gap: 6px; margin-bottom: 12px; }
.tag {
  font-size: 0.74rem; padding: 2px 9px; border-radius: 999px;
  background: #eef2ff; color: var(--accent-dark); border: 1px solid #e0e7ff;
}
.tag.green { background: var(--green-bg); color: #15803d; border-color: var(--green-rule); }
.tag.amber { background: var(--amber-bg); color: #b45309; border-color: var(--amber-rule); }
.tag.gray { background: #f3f4f6; color: #4b5563; border-color: #e5e7eb; }
.tool-card .foot { display: flex; align-items: center; justify-content: space-between; font-size: 0.82rem; color: var(--muted); }
.stars { color: #f59e0b; letter-spacing: 1px; }
.stars .num { color: var(--ink); font-weight: 700; margin-left: 4px; }

/* ---------- 行业入口 ---------- */
.industry-card { position: relative; overflow: hidden; cursor: pointer; }
.industry-card .ic-icon { font-size: 1.8rem; margin-bottom: 10px; }
.industry-card .ic-count { font-size: 0.8rem; color: var(--accent); font-weight: 600; margin-top: 8px; }
.industry-card:hover .ic-arrow { transform: translateX(4px); }
.ic-arrow { position: absolute; right: 16px; top: 50%; transform: translateY(-50%); color: var(--accent); font-size: 1.2rem; transition: transform 0.15s; }

/* ---------- 域名卡片 ---------- */
.domain-card { display: flex; flex-direction: column; }
.domain-card .d-name { font-family: 'Courier New', monospace; font-weight: 700; font-size: 1.05rem; color: var(--accent-dark); word-break: break-all; }
.domain-card .d-grade { font-size: 0.72rem; font-weight: 700; padding: 2px 8px; border-radius: 999px; }
.d-grade.A { background: var(--amber-bg); color: #b45309; border: 1px solid var(--amber-rule); }
.d-grade.B { background: #eef2ff; color: var(--accent); border: 1px solid #e0e7ff; }
.d-grade.C { background: #f3f4f6; color: #4b5563; border: 1px solid #e5e7eb; }
.domain-card .d-meaning { color: #374151; font-size: 0.88rem; margin: 8px 0; flex: 1; }
.domain-card .d-foot { display: flex; justify-content: space-between; align-items: center; font-size: 0.82rem; color: var(--muted); }
.domain-card .d-price { color: var(--amber); font-weight: 600; }
.src-badge { font-size: 0.7rem; padding: 1px 7px; border-radius: 999px; }
.src-badge.platform { background: #eef2ff; color: var(--accent); border: 1px solid #e0e7ff; }
.src-badge.user { background: var(--green-bg); color: #15803d; border: 1px solid var(--green-rule); }

/* ---------- 筛选栏 ---------- */
.filter-bar {
  background: var(--bg2); border: 1px solid var(--rule); border-radius: var(--radius);
  padding: 16px 20px; margin-bottom: 22px; display: flex; gap: 14px; flex-wrap: wrap; align-items: center;
}
.filter-bar .fb-group { display: flex; gap: 6px; flex-wrap: wrap; align-items: center; }
.filter-bar .fb-label { font-size: 0.82rem; color: var(--muted); font-weight: 600; }
.chip {
  font-size: 0.82rem; padding: 5px 13px; border-radius: 999px; cursor: pointer;
  border: 1px solid var(--rule); background: #fff; color: var(--ink);
}
.chip:hover { border-color: #c7d2fe; }
.chip.active { background: var(--accent); color: #fff; border-color: var(--accent); }
.search-input {
  flex: 1; min-width: 180px; padding: 9px 14px; border-radius: 9px;
  border: 1px solid var(--rule); font-size: 0.9rem; outline: none;
}
.search-input:focus { border-color: var(--accent); }

/* ---------- 表单 ---------- */
.form-card { background: var(--bg2); border: 1px solid var(--rule); border-radius: 14px; padding: 26px 28px; max-width: 640px; margin: 0 auto; }
.form-row { margin-bottom: 16px; }
.form-row label { display: block; font-size: 0.88rem; font-weight: 600; margin-bottom: 6px; }
.form-row input, .form-row select, .form-row textarea {
  width: 100%; padding: 10px 14px; border-radius: 9px;
  border: 1px solid var(--rule); font-size: 0.92rem; font-family: inherit; outline: none; background: #fff;
}
.form-row input:focus, .form-row select:focus, .form-row textarea:focus { border-color: var(--accent); box-shadow: 0 0 0 3px rgba(79,70,229,0.1); }
.form-row textarea { min-height: 110px; resize: vertical; }
.form-hint { font-size: 0.78rem; color: var(--muted); margin-top: 4px; }

/* ---------- 模态框 ---------- */
.modal-overlay {
  display: none; position: fixed; inset: 0; z-index: 200;
  background: rgba(15, 23, 42, 0.55); padding: 30px 16px; overflow-y: auto;
}
.modal-overlay.open { display: flex; align-items: flex-start; justify-content: center; }
.modal {
  background: #fff; border-radius: 16px; max-width: 720px; width: 100%;
  padding: 30px 32px; position: relative; margin: auto 0; box-shadow: 0 24px 60px rgba(0,0,0,0.25);
}
.modal-close { position: absolute; top: 14px; right: 16px; background: none; border: none; font-size: 1.5rem; cursor: pointer; color: var(--muted); }
.modal h2 { font-size: 1.35rem; margin-bottom: 6px; }
.modal .m-sub { color: var(--muted); font-size: 0.9rem; margin-bottom: 16px; }
.modal .m-sec { margin-top: 14px; }
.modal .m-sec h4 { font-size: 0.95rem; margin-bottom: 6px; }
.modal .m-sec p { color: #374151; font-size: 0.92rem; }
.modal .m-meta { display: flex; gap: 8px; flex-wrap: wrap; margin: 12px 0; }
.modal .m-actions { display: flex; gap: 10px; margin-top: 20px; flex-wrap: wrap; }

/* ---------- 定价表 ---------- */
.tbl-wrap { overflow-x: auto; margin: 14px 0 20px; border: 1px solid var(--rule); border-radius: var(--radius); background: var(--bg2); }
table { width: 100%; border-collapse: collapse; font-size: 0.92rem; min-width: 560px; }
th { background: #f1f3fa; text-align: left; padding: 10px 14px; font-weight: 700; font-size: 0.85rem; white-space: nowrap; border-bottom: 1px solid var(--rule); }
td { padding: 10px 14px; border-bottom: 1px solid var(--rule); vertical-align: top; }
tr:last-child td { border-bottom: none; }
tbody tr:nth-child(even) { background: #fafbfe; }

/* ---------- 提示框 ---------- */
.callout { border-radius: 12px; padding: 18px 22px; margin: 18px 0; font-size: 0.95rem; }
.callout.warn { background: var(--amber-bg); border: 1px solid var(--amber-rule); color: #92400e; }
.callout.red { background: var(--red-bg); border: 1px solid var(--red-rule); color: #991b1b; }
.callout.green { background: var(--green-bg); border: 1px solid var(--green-rule); color: #166534; }
.callout.blue { background: #eff6ff; border: 1px solid #bfdbfe; color: #1e40af; }
.callout b { font-weight: 700; }

/* ---------- 步骤条 ---------- */
.steps { display: grid; grid-template-columns: repeat(5, 1fr); gap: 12px; margin: 20px 0; }
.step { background: var(--bg2); border: 1px solid var(--rule); border-radius: var(--radius); padding: 16px; text-align: center; }
.step .s-idx { width: 30px; height: 30px; margin: 0 auto 8px; border-radius: 50%; background: linear-gradient(135deg, var(--accent), var(--accent2)); color: #fff; font-weight: 700; display: flex; align-items: center; justify-content: center; font-size: 0.85rem; }
.step h4 { font-size: 0.92rem; margin-bottom: 4px; }
.step p { font-size: 0.8rem; color: var(--muted); }
@media (max-width: 760px) { .steps { grid-template-columns: repeat(2, 1fr); } }

/* ---------- 页脚 ---------- */
footer { margin-top: 56px; background: #14182b; color: #9ca3af; padding: 40px 24px 28px; font-size: 0.86rem; }
.footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 30px; max-width: 1080px; margin: 0 auto; }
.footer-grid h4 { color: #e5e7eb; font-size: 0.92rem; margin-bottom: 10px; }
.footer-grid a { color: #9ca3af; display: block; padding: 3px 0; }
.footer-grid a:hover { color: #fff; }
.footer-brand { font-weight: 700; color: #fff; font-size: 1.05rem; margin-bottom: 6px; }
.footer-bottom { max-width: 1080px; margin: 28px auto 0; padding-top: 18px; border-top: 1px solid rgba(255,255,255,0.12); text-align: center; }
.footer-bottom a { color: #9ca3af; }
.icp-link { color: #c7d2fe !important; }
@media (max-width: 760px) { .footer-grid { grid-template-columns: 1fr 1fr; } }

/* ---------- 工具页 ---------- */
.page-hero { background: linear-gradient(135deg, #0f172a, #4f46e5); color: #fff; padding: 52px 24px 46px; text-align: center; }
.page-hero h1 { font-size: 1.9rem; margin-bottom: 8px; }
.page-hero p { opacity: 0.9; max-width: 680px; margin: 0 auto; }
.crumbs { font-size: 0.82rem; color: var(--muted); margin: 20px 0 6px; }
.crumbs a { color: var(--muted); }
.crumbs a:hover { color: var(--accent); }

/* 空状态 / 提示 */
.empty { text-align: center; padding: 48px 20px; color: var(--muted); }
.hidden { display: none !important; }

/* 通用 */
.text-center { text-align: center; }
.mt-1 { margin-top: 8px; } .mt-2 { margin-top: 16px; } .mt-3 { margin-top: 24px; } .mt-4 { margin-top: 32px; }
.mb-2 { margin-bottom: 16px; } .mb-3 { margin-bottom: 24px; }
.flex-between { display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap; gap: 10px; }