/* Linear + Density design system — analytics-takehome */
:root[data-theme="light"] {
  --bg: #ffffff;
  --surface: #fafafa;
  --surface-2: #f4f4f5;
  --border: #e5e5e7;
  --border-strong: #d4d4d8;
  --text: #09090b;
  --text-dim: #52525b;
  --text-muted: #a1a1aa;
  --accent: #6366f1;
  --accent-hover: #4f46e5;
  --accent-bg: rgba(99, 102, 241, 0.08);
  --accent-contrast: #ffffff;
  --success: #16a34a;
  --warning: #d97706;
  --danger: #dc2626;
  --blue: #2563eb;
  --orange: #ea580c;
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.04);
  --shadow-md: 0 2px 8px rgba(0,0,0,0.06);
  --cat-onboarding: #2563eb;
  --cat-usage: #6366f1;
  --cat-monetization: #ea580c;
}

:root[data-theme="dark"] {
  --bg: #0a0a0f;
  --surface: #111118;
  --surface-2: #17171f;
  --border: #1f1f2a;
  --border-strong: #2a2a36;
  --text: #f5f5f7;
  --text-dim: #a1a1aa;
  --text-muted: #71717a;
  --accent: #818cf8;
  --accent-hover: #6366f1;
  --accent-bg: rgba(99,102,241,0.12);
  --accent-contrast: #000000;
  --success: #22c55e;
  --warning: #f59e0b;
  --danger: #ef4444;
  --blue: #3b82f6;
  --orange: #f97316;
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.3);
  --shadow-md: 0 2px 8px rgba(0,0,0,0.4);
  --cat-onboarding: #3b82f6;
  --cat-usage: #818cf8;
  --cat-monetization: #f97316;
}

*{margin:0;padding:0;box-sizing:border-box;min-width:0}
html,body{
  font-family:'Geist',-apple-system,BlinkMacSystemFont,'Segoe UI',Roboto,sans-serif;
  background:var(--bg);color:var(--text);
  font-feature-settings:"ss01","cv11";
  -webkit-font-smoothing:antialiased;
  letter-spacing:-0.011em;font-size:15px;line-height:1.5;
}
.mono{font-family:'Geist Mono',ui-monospace,SFMono-Regular,Consolas,monospace;font-feature-settings:"tnum";font-variant-numeric:tabular-nums}
a{color:inherit}button{font-family:inherit;cursor:pointer}

/* Topbar */
.topbar{height:52px;border-bottom:1px solid var(--border);display:flex;align-items:center;padding:0 20px;gap:0;background:var(--bg);position:sticky;top:0;z-index:100}
.logo{display:flex;align-items:center;gap:8px;margin-right:24px;flex-shrink:0}
.logo-icon{width:24px;height:24px;background:var(--accent);border-radius:6px;display:flex;align-items:center;justify-content:center;color:#fff;font-weight:700;font-size:11px}
.logo-text{font-weight:600;font-size:14px;color:var(--text)}
.logo-sub{font-size:12px;color:var(--text-muted);margin-left:2px}

/* Tabs */
.tabs{display:flex;gap:0;overflow-x:auto;flex:1;scrollbar-width:none}
.tabs::-webkit-scrollbar{display:none}
.tab-btn{height:52px;padding:0 16px;border:none;background:transparent;color:var(--text-dim);font-size:14px;font-weight:500;border-bottom:2px solid transparent;white-space:nowrap;transition:color 0.15s;flex-shrink:0;letter-spacing:-0.011em}
.tab-btn:hover{color:var(--text)}
.tab-btn.active{color:var(--accent);border-bottom-color:var(--accent)}

.topbar-right{display:flex;align-items:center;gap:8px;margin-left:auto;flex-shrink:0}
.icon-btn{width:28px;height:28px;border:1px solid var(--border);border-radius:6px;background:transparent;color:var(--text-dim);display:flex;align-items:center;justify-content:center;transition:all 0.15s}
.icon-btn:hover{color:var(--text);border-color:var(--border-strong)}
.icon-moon{display:none}
[data-theme="dark"] .icon-sun{display:none}
[data-theme="dark"] .icon-moon{display:block}

/* Content */
.content{max-width:1100px;margin:0 auto;padding:32px 24px}
.tab-panel{display:none}
.tab-panel.active{display:block}

/* Page header */
.page-header{margin-bottom:28px}
.page-title{font-size:24px;font-weight:600;letter-spacing:-0.03em;color:var(--text)}
.page-desc{font-size:15px;color:var(--text-dim);margin-top:4px}

/* Section */
.section{margin-bottom:32px}
.section-title{font-size:16px;font-weight:600;color:var(--text);margin-bottom:12px;letter-spacing:-0.02em}
.section-desc{font-size:15px;color:var(--text-dim);margin-bottom:16px;line-height:1.6}

/* KPI Cards */
.kpi-row{display:grid;grid-template-columns:repeat(3,1fr);gap:12px;margin-bottom:24px}
.kpi-card{background:var(--surface);border:1px solid var(--border);border-radius:10px;padding:16px 20px}
.kpi-label{font-size:12px;font-weight:500;color:var(--text-muted);text-transform:uppercase;letter-spacing:0.05em;margin-bottom:6px}
.kpi-value{font-size:28px;font-weight:600;letter-spacing:-0.04em;color:var(--text);line-height:1}
.kpi-delta{font-size:12px;margin-top:4px}
.kpi-delta.up{color:var(--success)}
.kpi-delta.stable{color:var(--text-muted)}

/* Charts */
.charts-grid{display:grid;grid-template-columns:1fr 1fr;gap:16px;margin-bottom:24px}
.chart-card{background:var(--surface);border:1px solid var(--border);border-radius:10px;padding:20px}
.chart-card.full{grid-column:1/-1}
.chart-title{font-size:15px;font-weight:600;color:var(--text);margin-bottom:4px}
.chart-sub{font-size:12px;color:var(--text-muted);margin-bottom:16px}
.chart-wrap{position:relative;height:200px}
.chart-wrap.tall{height:260px}

/* Table */
.table-wrap{overflow-x:auto;border:1px solid var(--border);border-radius:10px}
table{width:100%;border-collapse:collapse}
th{background:var(--surface);padding:10px 14px;text-align:left;font-size:12px;font-weight:600;color:var(--text-muted);text-transform:uppercase;letter-spacing:0.04em;border-bottom:1px solid var(--border);white-space:nowrap}
td{padding:10px 14px;border-bottom:1px solid var(--border);font-size:14px;color:var(--text);vertical-align:top;line-height:1.5}
tr:last-child td{border-bottom:none}
tr:hover td{background:var(--surface)}

/* Badge */
.badge{display:inline-flex;align-items:center;padding:2px 8px;border-radius:4px;font-size:12px;font-weight:600;font-family:'Geist Mono',monospace;white-space:nowrap}
.badge-blue{background:rgba(37,99,235,0.1);color:var(--cat-onboarding)}
.badge-indigo{background:rgba(99,102,241,0.1);color:var(--cat-usage)}
.badge-orange{background:rgba(234,88,12,0.1);color:var(--cat-monetization)}
.code{font-family:'Geist Mono',monospace;font-size:12px;background:var(--surface-2);padding:1px 5px;border-radius:3px;color:var(--accent)}

/* Funnel Steps */
.funnel-block{background:var(--surface);border:1px solid var(--border);border-radius:10px;padding:20px;margin-bottom:16px}
.funnel-title{font-size:16px;font-weight:600;color:var(--text);margin-bottom:4px}
.funnel-goal{font-size:13px;color:var(--text-muted);margin-bottom:16px}
.funnel-steps{display:flex;flex-direction:column;gap:0}
.funnel-step{display:flex;gap:12px;align-items:flex-start}
.funnel-step-left{display:flex;flex-direction:column;align-items:center;flex-shrink:0}
.step-dot{width:28px;height:28px;border-radius:50%;background:var(--accent-bg);border:2px solid var(--accent);display:flex;align-items:center;justify-content:center;font-size:11px;font-weight:700;color:var(--accent);flex-shrink:0}
.step-line{width:2px;flex:1;background:var(--border);min-height:20px;margin:2px 0}
.step-content{padding-bottom:16px;flex:1}
.step-event{font-size:13px;font-weight:600;font-family:'Geist Mono',monospace;color:var(--accent);margin-bottom:2px}
.step-why{font-size:14px;color:var(--text-dim);line-height:1.5}
.step-dropoff{display:inline-flex;align-items:center;gap:4px;margin-top:4px;font-size:12px;color:var(--warning);background:rgba(217,119,6,0.08);padding:3px 8px;border-radius:4px}

/* Risk Cards */
.risk-list{display:flex;flex-direction:column;gap:12px}
.risk-card{background:var(--surface);border:1px solid var(--border);border-radius:10px;padding:16px 20px;border-left:3px solid var(--danger)}
.risk-title{font-size:15px;font-weight:600;color:var(--text);margin-bottom:8px}
.risk-row{display:grid;grid-template-columns:90px 1fr;gap:8px;margin-top:6px;font-size:14px}
.risk-label{color:var(--text-muted);font-weight:500}
.risk-val{color:var(--text-dim);line-height:1.5}

/* Optimization Cards */
.opt-grid{display:grid;grid-template-columns:1fr 1fr;gap:12px}
.opt-card{background:var(--surface);border:1px solid var(--border);border-radius:10px;padding:16px 20px;border-left:3px solid var(--accent)}
.opt-title{font-size:15px;font-weight:600;color:var(--text);margin-bottom:10px}
.opt-row{margin-top:6px;font-size:14px}
.opt-row-label{font-size:11px;font-weight:600;text-transform:uppercase;letter-spacing:0.05em;color:var(--text-muted);margin-bottom:2px}
.opt-row-val{color:var(--text-dim);line-height:1.5}
.metric-pill{display:inline-flex;align-items:center;gap:4px;margin-top:6px;font-size:12px;color:var(--success);background:rgba(22,163,74,0.08);padding:3px 8px;border-radius:4px;font-weight:500}

/* Experiment Cards */
.exp-list{display:flex;flex-direction:column;gap:16px}
.exp-card{background:var(--surface);border:1px solid var(--border);border-radius:10px;padding:20px}
.exp-title{font-size:16px;font-weight:600;color:var(--text);margin-bottom:12px}
.exp-section{margin-top:12px}
.exp-section-label{font-size:11px;font-weight:600;text-transform:uppercase;letter-spacing:0.06em;color:var(--text-muted);margin-bottom:4px}
.hypothesis-box{background:var(--accent-bg);border:1px solid rgba(99,102,241,0.2);border-radius:6px;padding:10px 14px;font-size:14px;color:var(--text-dim);line-height:1.6;font-style:italic}
.flag-box{background:var(--surface-2);border-radius:6px;padding:10px 14px;font-size:12px;font-family:'Geist Mono',monospace;color:var(--text-dim);line-height:1.8}
.success-metric{font-size:14px;color:var(--text-dim);line-height:1.5}
.expected-pill{display:inline-flex;align-items:center;gap:4px;margin-top:8px;font-size:13px;color:var(--success);font-weight:500}

/* Retention cohort */
.cohort-table{width:100%;border-collapse:collapse}
.cohort-table th,.cohort-table td{padding:8px 12px;text-align:center;font-size:14px;border:1px solid var(--border)}
.cohort-table th{background:var(--surface-2);font-weight:600;color:var(--text-muted);font-size:12px}
.cohort-cell-high{background:rgba(99,102,241,0.25);color:var(--text)}
.cohort-cell-mid{background:rgba(99,102,241,0.12);color:var(--text)}
.cohort-cell-low{background:rgba(99,102,241,0.04);color:var(--text-dim)}

@media(max-width:768px){
  .charts-grid{grid-template-columns:1fr}
  .opt-grid{grid-template-columns:1fr}
  .kpi-row{grid-template-columns:1fr}
  .content{padding:24px 16px}
}