:root, [data-theme="light"] {
  --bg: #f8fafc;
  --card-bg: #ffffff;
  --border: #e2e8f0;
  --text: #0f172a;
  --text-muted: #64748b;
  --accent: #16a34a;
  --accent-bg: rgba(22, 163, 74, 0.08);
  --radius: 8px;
}

[data-theme="dark"] {
  --bg: #0a0a0c;
  --card-bg: #121216;
  --border: #22222a;
  --text: #f4f4f6;
  --text-muted: #8e8e9a;
  --accent: #22c55e;
  --accent-bg: rgba(34, 197, 94, 0.08);
  --radius: 8px;
}

* { box-sizing: border-box; margin: 0; padding: 0; font-family: 'Inter', system-ui, sans-serif; }
body { background: var(--bg); color: var(--text); padding: 40px 20px; display: flex; justify-content: center; }
.app-container { width: 100%; max-width: 540px; display: flex; flex-direction: column; gap: 20px; }

.navbar { display: flex; justify-content: space-between; align-items: center; padding-bottom: 12px; border-bottom: 1px solid var(--border); }
.logo { font-size: 1.05rem; font-weight: 700; display: flex; align-items: center; gap: 8px; }
.theme-btn { background: var(--card-bg); color: var(--text); border: 1px solid var(--border); border-radius: var(--radius); padding: 6px 10px; cursor: pointer; display: flex; align-items: center; }

.card { background: var(--card-bg); border: 1px solid var(--border); border-radius: var(--radius); padding: 24px; display: flex; flex-direction: column; gap: 20px; }
.header-text h1 { font-size: 1.25rem; font-weight: 700; margin-bottom: 4px; }
.header-text p { font-size: 0.85rem; color: var(--text-muted); }

.main-input-group { display: flex; flex-direction: column; gap: 8px; }
.main-input-group label { font-size: 0.82rem; font-weight: 600; color: var(--text-muted); text-transform: uppercase; letter-spacing: 0.5px; }

.input-row { display: flex; gap: 10px; }
.input-box { flex: 1; display: flex; align-items: center; border: 1px solid var(--border); border-radius: var(--radius); background: var(--bg); padding-right: 12px; }
.input-box input { flex: 1; padding: 12px 14px; border: none; background: transparent; color: var(--text); font-size: 1.2rem; font-weight: 700; outline: none; }
.currency { font-size: 1.1rem; font-weight: 600; color: var(--text-muted); }

.toggle-group { display: flex; background: var(--bg); border: 1px solid var(--border); border-radius: var(--radius); padding: 3px; gap: 2px; }
.toggle-btn { padding: 8px 14px; border: none; background: transparent; color: var(--text-muted); font-size: 0.85rem; font-weight: 600; border-radius: 6px; cursor: pointer; }
.toggle-btn.active { background: var(--card-bg); color: var(--text); border: 1px solid var(--border); }

.options-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 10px; }
.opt-group { display: flex; flex-direction: column; gap: 6px; }
.opt-group label { font-size: 0.78rem; color: var(--text-muted); font-weight: 500; }
.opt-group select, .opt-group input { padding: 10px; border: 1px solid var(--border); border-radius: var(--radius); background: var(--bg); color: var(--text); font-size: 0.85rem; outline: none; }

.result-hero { background: var(--accent-bg); border: 1px solid var(--accent); border-radius: var(--radius); padding: 20px; display: flex; flex-direction: column; gap: 16px; }
.result-primary { display: flex; flex-direction: column; gap: 2px; }
.result-primary .label { font-size: 0.8rem; color: var(--text-muted); text-transform: uppercase; font-weight: 600; }
.result-primary strong { font-size: 2.2rem; font-weight: 800; color: var(--accent); }

.metrics-row { display: grid; grid-template-columns: repeat(3, 1fr); gap: 10px; border-top: 1px solid rgba(34, 197, 94, 0.2); padding-top: 12px; }
.m-item { display: flex; flex-direction: column; gap: 2px; }
.m-item span { font-size: 0.75rem; color: var(--text-muted); }
.m-item strong { font-size: 0.95rem; font-weight: 600; }

.sources { font-size: 0.78rem; color: var(--text-muted); border-top: 1px solid var(--border); padding-top: 12px; }
.sources a { color: var(--text); text-decoration: underline; }

.ads-container { width: 100%; min-height: 90px; border: 1px dashed var(--border); border-radius: var(--radius); display: flex; align-items: center; justify-content: center; }
.footer { text-align: center; font-size: 0.78rem; color: var(--text-muted); padding: 10px 0; border-top: 1px solid var(--border); }

/* Mobile Responsive */
@media (max-width: 600px) {
  body { padding: 16px 12px; }
  .card { padding: 16px; }
  .input-row { flex-direction: column; }
  .options-grid { grid-template-columns: 1fr; }
  .metrics-row { grid-template-columns: 1fr; gap: 8px; }
  .result-primary strong { font-size: 1.8rem; }
}