:root {
  --primary: #1677ff;
  --primary-light: #e6f4ff;
  --primary-dark: #0958d9;
  --bg: #f5f7fa;
  --card: #ffffff;
  --text: #1f2329;
  --sub: #5c6670;
  --border: #e1e4e8;
  --danger: #ff4d4f;
  --success: #52c41a;
  --warning: #faad14;
  --shadow: 0 2px 12px rgba(0,0,0,0.06);
}

* { box-sizing: border-box; -webkit-tap-highlight-color: transparent; }
html, body { margin: 0; padding: 0; min-height: 100%; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "PingFang SC", "Microsoft YaHei", sans-serif; background: var(--bg); color: var(--text); font-size: 15px; }
.app { min-height: 100vh; display: flex; flex-direction: column; max-width: 1180px; margin: 0 auto; background: var(--bg); }

.app-header { background: linear-gradient(135deg, #1677ff 0%, #0958d9 100%); color: #fff; padding: 30px 24px 26px; }
.brand .badge { display: inline-block; font-size: 11px; font-weight: 700; letter-spacing: 0.6px; padding: 4px 10px; background: rgba(255,255,255,0.18); border-radius: 999px; margin-bottom: 10px; }
.brand h1 { margin: 0 0 6px; font-size: 26px; font-weight: 700; }
.brand p { margin: 0; opacity: 0.92; font-size: 13px; }

main { flex: 1; padding: 22px 18px 28px; width: 100%; }
.section-title { font-size: 15px; font-weight: 600; color: var(--sub); margin: 4px 0 12px; padding-left: 8px; border-left: 4px solid var(--primary); }

.card-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 12px; }
@media (min-width: 480px) { .card-grid { grid-template-columns: repeat(3, 1fr); gap: 14px; } }
@media (min-width: 768px) { .card-grid { grid-template-columns: repeat(4, 1fr); gap: 16px; } }
@media (min-width: 1080px) { .card-grid { grid-template-columns: repeat(6, 1fr); } }
.card { background: var(--card); border-radius: 14px; padding: 16px 12px 14px; box-shadow: var(--shadow); cursor: pointer; transition: transform .12s, box-shadow .12s; border: 1px solid transparent; }
.card:active { transform: scale(0.98); }
.card:hover { box-shadow: 0 4px 18px rgba(22,119,255,0.12); border-color: var(--primary-light); }
.card-icon { width: 38px; height: 38px; border-radius: 10px; background: var(--primary-light); color: var(--primary); display: flex; align-items: center; justify-content: center; font-size: 20px; margin-bottom: 10px; }
.card-title { font-size: 15px; font-weight: 700; color: var(--text); margin-bottom: 4px; }
.card-sub { font-size: 11px; color: var(--sub); line-height: 1.35; }

.page { display: none; }
.page.active { display: block; animation: fadeIn .2s ease; }
@keyframes fadeIn { from { opacity: 0; transform: translateY(6px); } to { opacity: 1; transform: translateY(0); } }

.tool-header { display: flex; align-items: center; gap: 12px; margin-bottom: 18px; }
.back-btn { background: #fff; border: 1px solid var(--border); color: var(--primary); font-size: 14px; font-weight: 600; padding: 8px 14px; border-radius: 10px; cursor: pointer; }
.tool-title { font-size: 20px; font-weight: 700; }

.tool-body { background: #fff; border-radius: 16px; padding: 20px; box-shadow: var(--shadow);
  display: grid; grid-template-columns: 1fr; gap: 14px 18px; align-content: start; }
.tool-body > *:not(.form-group) { grid-column: 1 / -1; }

.form-group { margin: 0; }
.form-group label { display: block; font-size: 13px; font-weight: 600; color: var(--sub); margin-bottom: 6px; }
.form-row { display: grid; grid-template-columns: 1fr auto; gap: 10px; align-items: end; }
.form-row select { min-width: 88px; }
input, select, textarea {
  width: 100%; padding: 11px 12px; border: 1px solid var(--border); border-radius: 10px; font-size: 15px; outline: none; background: #fff; color: var(--text);
}
input:focus, select:focus, textarea:focus { border-color: var(--primary); box-shadow: 0 0 0 3px var(--primary-light); }

/* 桌面端：输入字段多列网格；结果两列 */
@media (min-width: 600px) {
  .tool-body { grid-template-columns: repeat(2, 1fr); }
}
@media (min-width: 900px) {
  .tool-body { grid-template-columns: repeat(3, 1fr); padding: 26px; }
  main { padding: 28px 24px 40px; }
  .app-header { padding: 30px 32px 26px; }
}

.btn { width: 100%; padding: 12px; border-radius: 10px; border: none; font-size: 15px; font-weight: 600; cursor: pointer; margin-top: 8px; }
.btn-primary { background: var(--primary); color: #fff; }
.btn-primary:active { background: var(--primary-dark); }
.btn-ghost { background: #fff; color: var(--primary); border: 1px solid var(--primary); }

.result-card { background: #f6faff; border: 1px solid #d6e8ff; border-radius: 12px; padding: 14px 16px; }
.result-title { font-size: 13px; font-weight: 600; color: var(--primary-dark); margin-bottom: 10px; }
.result-grid { display: grid; grid-template-columns: 1fr; gap: 0 18px; }
@media (min-width: 760px) { .result-grid { grid-template-columns: repeat(2, 1fr); } }
.result-row { display: flex; justify-content: space-between; align-items: center; padding: 8px 0; border-bottom: 1px dashed #dbe6f5; }
.result-row:last-child { border-bottom: none; }
.result-label { color: var(--sub); font-size: 14px; }
.result-value { font-weight: 700; font-size: 15px; color: var(--text); text-align: right; }

.copy-bar { display: flex; gap: 10px; margin-top: 4px; }
.copy-bar .btn { margin-top: 0; }
@media (min-width: 600px) { .copy-bar .btn { width: auto; padding: 12px 22px; } }

.formula-box { background: #fafafa; border-radius: 10px; padding: 12px; font-size: 12px; color: var(--sub); line-height: 1.7; }
.formula-box b { color: var(--text); }

.toast { position: fixed; left: 50%; bottom: 80px; transform: translateX(-50%) translateY(20px); background: rgba(0,0,0,0.78); color: #fff; padding: 10px 18px; border-radius: 20px; font-size: 14px; opacity: 0; pointer-events: none; transition: opacity .2s, transform .2s; }
.toast.show { opacity: 1; transform: translateX(-50%) translateY(0); }

.app-footer { text-align: center; font-size: 12px; color: #aaa; padding: 18px; }

.tabs { display: flex; gap: 8px; margin-bottom: 4px; overflow-x: auto; }
.tab { flex: 1; text-align: center; padding: 10px; border-radius: 10px; background: #f0f2f5; color: var(--sub); font-size: 13px; font-weight: 600; cursor: pointer; white-space: nowrap; }
.tab.active { background: var(--primary-light); color: var(--primary); }

.status { display: inline-block; padding: 2px 8px; border-radius: 999px; font-size: 12px; font-weight: 700; }
.status.ok { background: #f6ffed; color: var(--success); }
.status.warn { background: #fffbe6; color: var(--warning); }
.status.bad { background: #fff1f0; color: var(--danger); }

/* 套管振动专用 */
.verdict { text-align: center; font-size: 16px; font-weight: 700; padding: 12px; border-radius: 12px; }
.verdict.ok { background: #f6ffed; color: var(--success); border: 1px solid #b7eb8f; }
.verdict.bad { background: #fff1f0; color: var(--danger); border: 1px solid #ffa39e; }
.badge-row { display: flex; flex-wrap: wrap; gap: 8px; }
.note { font-size: 12px; color: #ad6800; background: #fffbe6; border: 1px solid #ffe58f; border-radius: 8px; padding: 8px 10px; margin: 0; line-height: 1.5; }
.adv { margin: 0; border: 1px solid var(--border); border-radius: 10px; padding: 0 12px; background: #fafafa; }
.adv summary { cursor: pointer; padding: 10px 0; font-size: 13px; font-weight: 600; color: var(--sub); outline: none; }
.adv[open] summary { border-bottom: 1px solid var(--border); margin-bottom: 10px; }
.adv .form-group { margin-bottom: 14px; }

/* 广告位（预留展示区，后续可接微信流量主 / 穿山甲 / 腾讯广告联盟） */
.ad-slot { grid-column: 1 / -1; display: flex; align-items: center; gap: 10px; background: repeating-linear-gradient(45deg, #fafbff, #fafbff 12px, #f0f3ff 12px, #f0f3ff 24px); border: 1px dashed #b8c6e6; border-radius: 12px; padding: 14px 16px; margin: 4px 0; }
.ad-tag { flex: none; font-size: 11px; font-weight: 700; color: #fff; background: #95a5c9; padding: 2px 8px; border-radius: 6px; }
.ad-content { font-size: 14px; font-weight: 600; color: #6b7896; line-height: 1.4; }
.ad-content small { font-weight: 400; color: #97a2bd; }