:root {
    --primary: #2563eb;
    --primary-hover: #1d4ed8;
    --primary-light: #dbeafe;
    --success: #16a34a;
    --success-light: #dcfce7;
    --warning: #f59e0b;
    --warning-light: #fef3c7;
    --danger: #dc2626;
    --danger-light: #fee2e2;
    --bg: #f8fafc;
    --surface: #ffffff;
    --border: #e2e8f0;
    --text: #1e293b;
    --text-muted: #64748b;
    --radius: 12px;
    --radius-sm: 8px;
    --shadow: 0 1px 3px rgba(0,0,0,0.08), 0 1px 2px rgba(0,0,0,0.06);
    --shadow-lg: 0 10px 25px rgba(0,0,0,0.1);
    --transition: 0.2s ease;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, system-ui, sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
    min-height: 100vh;
}

.container { max-width: 1100px; margin: 0 auto; padding: 0 20px; }

/* Header */
.header {
    background: var(--surface);
    border-bottom: 1px solid var(--border);
    position: sticky; top: 0; z-index: 100;
    backdrop-filter: blur(10px);
}
.header .container { display: flex; align-items: center; justify-content: space-between; padding: 12px 20px; }
.logo { display: flex; align-items: center; gap: 10px; text-decoration: none; font-size: 1.3rem; font-weight: 700; color: var(--primary); }
.nav { display: flex; gap: 4px; }
.nav-link {
    background: none; border: none; padding: 8px 16px; border-radius: var(--radius-sm);
    cursor: pointer; font-size: 0.9rem; color: var(--text-muted); transition: var(--transition);
}
.nav-link:hover { background: var(--bg); color: var(--text); }
.nav-link.active { background: var(--primary-light); color: var(--primary); font-weight: 600; }

/* Panels */
.panel { display: none; }
.panel.active { display: block; }
.panel-header { text-align: center; padding: 32px 0 24px; }
.panel-header h1 { font-size: 1.8rem; font-weight: 800; }
.panel-header p { color: var(--text-muted); margin-top: 4px; }

/* Form */
.search-form {
    background: var(--surface); border-radius: var(--radius); padding: 28px;
    box-shadow: var(--shadow-lg); margin-bottom: 24px;
}
.form-row { display: flex; gap: 12px; margin-bottom: 16px; flex-wrap: wrap; }
.trip-type-row { gap: 8px; }
.cities-row .form-group { flex: 1; }
.swap-btn {
    width: 40px; height: 40px; border-radius: 50%; border: 2px solid var(--border);
    background: var(--surface); font-size: 1.2rem; cursor: pointer; align-self: flex-end;
    margin-bottom: 5px; transition: var(--transition);
}
.swap-btn:hover { border-color: var(--primary); color: var(--primary); }
.form-group { display: flex; flex-direction: column; gap: 6px; min-width: 140px; flex: 1; }
.form-group label { font-size: 0.85rem; font-weight: 600; color: var(--text-muted); text-transform: uppercase; letter-spacing: 0.5px; }
.form-group input, .form-group select {
    padding: 10px 14px; border: 2px solid var(--border); border-radius: var(--radius-sm);
    font-size: 0.95rem; background: var(--surface); transition: var(--transition);
}
.form-group input:focus, .form-group select:focus {
    outline: none; border-color: var(--primary); box-shadow: 0 0 0 3px var(--primary-light);
}
.form-group small { font-size: 0.8rem; color: var(--text-muted); }
.form-group small a { color: var(--primary); }

/* Radio chips */
.radio-chip { position: relative; cursor: pointer; }
.radio-chip input { position: absolute; opacity: 0; }
.radio-chip span {
    display: block; padding: 8px 18px; border: 2px solid var(--border);
    border-radius: 50px; font-size: 0.9rem; font-weight: 500; transition: var(--transition);
}
.radio-chip input:checked + span {
    background: var(--primary); color: #fff; border-color: var(--primary);
}

/* Filters */
.filters-section {
    margin-bottom: 16px; border: 1px solid var(--border); border-radius: var(--radius-sm); padding: 14px 18px;
}
.filters-section summary { cursor: pointer; font-weight: 600; color: var(--text-muted); user-select: none; }
.filters-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(180px, 1fr)); gap: 12px; margin-top: 14px; }

/* Actions */
.form-actions { display: flex; align-items: center; justify-content: space-between; gap: 16px; flex-wrap: wrap; }
.checkbox-label { display: flex; align-items: center; gap: 8px; cursor: pointer; font-size: 0.9rem; color: var(--text-muted); }

/* Buttons */
.btn {
    padding: 10px 20px; border: none; border-radius: var(--radius-sm); font-size: 0.95rem;
    font-weight: 600; cursor: pointer; transition: var(--transition); display: inline-flex; align-items: center; gap: 6px;
}
.btn-primary { background: var(--primary); color: #fff; }
.btn-primary:hover { background: var(--primary-hover); transform: translateY(-1px); box-shadow: var(--shadow); }
.btn-secondary { background: var(--bg); color: var(--text); border: 2px solid var(--border); }
.btn-secondary:hover { border-color: var(--text-muted); }
.btn-danger-outline { background: none; color: var(--danger); border: 2px solid var(--danger); }
.btn-danger-outline:hover { background: var(--danger-light); }
.btn-lg { padding: 14px 32px; font-size: 1.05rem; }
.btn-sm { padding: 6px 14px; font-size: 0.85rem; }

/* Results */
.results-header { display: flex; justify-content: space-between; align-items: center; margin-bottom: 16px; }
.results-header h2 { font-size: 1.3rem; }
.results-list { display: flex; flex-direction: column; gap: 12px; }
.flight-card {
    background: var(--surface); border-radius: var(--radius); padding: 20px;
    box-shadow: var(--shadow); border-left: 4px solid var(--border); transition: var(--transition);
    display: grid; grid-template-columns: 1fr auto; gap: 16px; align-items: center;
}
.flight-card:hover { box-shadow: var(--shadow-lg); transform: translateY(-1px); }
.flight-card.score-high { border-left-color: var(--success); }
.flight-card.score-mid { border-left-color: var(--warning); }
.flight-card.score-low { border-left-color: var(--danger); }
.flight-info { display: flex; flex-direction: column; gap: 8px; }
.flight-route { display: flex; align-items: center; gap: 12px; font-size: 1.1rem; font-weight: 700; }
.flight-route .arrow { color: var(--text-muted); }
.flight-details { display: flex; gap: 16px; font-size: 0.85rem; color: var(--text-muted); flex-wrap: wrap; }
.flight-badge {
    display: inline-block; padding: 2px 8px; border-radius: 50px; font-size: 0.75rem; font-weight: 600;
}
.badge-nonstop { background: var(--success-light); color: var(--success); }
.badge-1stop { background: var(--warning-light); color: var(--warning); }
.badge-2stop { background: var(--danger-light); color: var(--danger); }
.flight-right { text-align: right; display: flex; flex-direction: column; align-items: flex-end; gap: 8px; }
.flight-price { font-size: 1.6rem; font-weight: 800; color: var(--text); }
.flight-price small { font-size: 0.8rem; color: var(--text-muted); font-weight: 400; }
.score-badge {
    display: inline-flex; align-items: center; gap: 4px; padding: 4px 12px;
    border-radius: 50px; font-size: 0.85rem; font-weight: 700;
}
.score-badge.green { background: var(--success-light); color: var(--success); }
.score-badge.yellow { background: var(--warning-light); color: #b45309; }
.score-badge.red { background: var(--danger-light); color: var(--danger); }
.reminders-box {
    background: #f0f9ff; border-radius: var(--radius-sm); padding: 10px 14px;
    font-size: 0.8rem; color: var(--text-muted); border: 1px solid #bae6fd;
}

/* Loader */
.loader { text-align: center; padding: 40px; }
.spinner {
    width: 40px; height: 40px; border: 4px solid var(--border);
    border-top-color: var(--primary); border-radius: 50%; animation: spin 0.8s linear infinite; margin: 0 auto 12px;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* Empty state */
.empty-state { text-align: center; padding: 40px; color: var(--text-muted); }

/* Price Calendar */
#price-calendar { margin-top: 24px; background: var(--surface); border-radius: var(--radius); padding: 20px; box-shadow: var(--shadow); }
#price-calendar h3 { margin-bottom: 16px; }
.calendar-grid { display: grid; grid-template-columns: repeat(7, 1fr); gap: 4px; text-align: center; }
.calendar-day {
    padding: 11px 4px; border-radius: var(--radius-sm); font-size: 0.8rem; cursor: pointer;
    border: 1px solid transparent; transition: var(--transition);
}
.calendar-day:hover { border-color: var(--primary); background: var(--primary-light); }
.calendar-day.best { background: #dcfce7; border-color: #86efac; font-weight: 700; }
.calendar-day.good { background: #fef3c7; }
.calendar-day.expensive { background: #fee2e2; }
.calendar-day.cheapest { background: #22c55e; color: #fff; font-weight: 800; }
.calendar-day.no-data { color: #ccc; cursor: default; }
.calendar-day.selected { border: 2px solid var(--primary); }
.calendar-dayhead { font-weight: 600; font-size: 0.75rem; color: var(--text-muted); padding: 8px; }

/* Tracking */
.tracking-controls { display: flex; gap: 10px; margin-bottom: 20px; }
.tracking-list { display: flex; flex-direction: column; gap: 12px; }
.track-card {
    background: var(--surface); border-radius: var(--radius); padding: 20px;
    box-shadow: var(--shadow); display: grid; grid-template-columns: 1fr auto auto; gap: 16px; align-items: center;
}
.track-route { font-size: 1.1rem; font-weight: 700; }
.track-meta { font-size: 0.85rem; color: var(--text-muted); display: flex; gap: 16px; flex-wrap: wrap; }
.track-prices { text-align: right; }
.track-current { font-size: 1.3rem; font-weight: 800; }
.track-target { font-size: 0.85rem; color: var(--text-muted); }
.track-actions { display: flex; gap: 6px; }

/* Profile */
.profile-form { background: var(--surface); border-radius: var(--radius); padding: 24px; box-shadow: var(--shadow); margin-bottom: 20px; }
.profile-saved h3 { margin-bottom: 14px; }
.api-section { background: var(--surface); border-radius: var(--radius); padding: 24px; box-shadow: var(--shadow); }
.api-section h3 { margin-bottom: 14px; }

/* Toast */
.toast {
    position: fixed; bottom: 24px; right: 24px; z-index: 200;
    background: var(--text); color: #fff; padding: 14px 24px; border-radius: var(--radius-sm);
    box-shadow: var(--shadow-lg); font-size: 0.9rem; animation: slideUp 0.3s ease;
}
.toast.success { background: var(--success); }
.toast.error { background: var(--danger); }
@keyframes slideUp { from { transform: translateY(20px); opacity: 0; } to { transform: translateY(0); opacity: 1; } }

/* Modal */
.modal {
    position: fixed; inset: 0; z-index: 300; background: rgba(0,0,0,0.5);
    display: flex; align-items: center; justify-content: center;
}
.modal-content {
    background: var(--surface); border-radius: var(--radius); padding: 32px;
    max-width: 440px; width: 90%; text-align: center; box-shadow: var(--shadow-lg);
}
.modal-content h2 { margin-bottom: 12px; }
.modal-actions { display: flex; gap: 10px; justify-content: center; margin-top: 20px; }

/* Status badge */
.status-badge { display: inline-block; padding: 4px 10px; border-radius: 50px; font-size: 0.8rem; font-weight: 600; }
.status-badge.ok { background: var(--success-light); color: var(--success); }
.status-badge.err { background: var(--danger-light); color: var(--danger); }

/* Responsive */
@media (max-width: 768px) {
    .cities-row { flex-direction: column; }
    .swap-btn { align-self: center; transform: rotate(90deg); margin: -8px 0; }
    .flight-card { grid-template-columns: 1fr; }
    .flight-right { text-align: left; align-items: flex-start; }
    .track-card { grid-template-columns: 1fr; }
    .form-row { flex-direction: column; }
    .form-actions { flex-direction: column; align-items: stretch; }
}