/* ================================================================
   Pricing Strategy Simulator -- Main Stylesheet
   ================================================================ */

/* ---- Reset & Base ---- */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

:root {
    --primary: #2563eb;
    --primary-dark: #1d4ed8;
    --primary-light: #dbeafe;
    --secondary: #7c3aed;
    --success: #059669;
    --success-light: #d1fae5;
    --danger: #dc2626;
    --danger-light: #fee2e2;
    --warning: #d97706;
    --warning-light: #fef3c7;
    --info: #0284c7;
    --info-light: #e0f2fe;
    --gray-50: #f9fafb;
    --gray-100: #f3f4f6;
    --gray-200: #e5e7eb;
    --gray-300: #d1d5db;
    --gray-400: #9ca3af;
    --gray-500: #6b7280;
    --gray-600: #4b5563;
    --gray-700: #374151;
    --gray-800: #1f2937;
    --gray-900: #111827;
    --white: #ffffff;
    --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
    --shadow: 0 1px 3px rgba(0,0,0,0.1), 0 1px 2px rgba(0,0,0,0.06);
    --shadow-md: 0 4px 6px rgba(0,0,0,0.1), 0 2px 4px rgba(0,0,0,0.06);
    --shadow-lg: 0 10px 15px rgba(0,0,0,0.1), 0 4px 6px rgba(0,0,0,0.05);
    --radius: 8px;
    --radius-lg: 12px;
    --transition: 0.2s ease;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
                 "Helvetica Neue", Arial, sans-serif;
    background: var(--gray-50);
    color: var(--gray-800);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* ---- Navbar ---- */
.navbar {
    background: var(--white);
    border-bottom: 1px solid var(--gray-200);
    padding: 0 2rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 64px;
    box-shadow: var(--shadow-sm);
    position: sticky;
    top: 0;
    z-index: 100;
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.nav-brand h1 {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--primary);
}

.nav-icon {
    font-size: 1.5rem;
    color: var(--primary);
}

.nav-links {
    display: flex;
    gap: 0.25rem;
}

.nav-link {
    padding: 0.5rem 1rem;
    border-radius: var(--radius);
    text-decoration: none;
    color: var(--gray-600);
    font-weight: 500;
    font-size: 0.9rem;
    transition: all var(--transition);
}

.nav-link:hover {
    background: var(--gray-100);
    color: var(--primary);
}

.nav-link.active {
    background: var(--primary-light);
    color: var(--primary-dark);
}

/* ---- Container ---- */
.container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 2rem;
    flex: 1;
    width: 100%;
}

/* ---- Cards ---- */
.card {
    background: var(--white);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow);
    padding: 1.5rem;
    margin-bottom: 1.5rem;
    border: 1px solid var(--gray-200);
    transition: box-shadow var(--transition);
}

.card:hover {
    box-shadow: var(--shadow-md);
}

.card-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
    padding-bottom: 0.75rem;
    border-bottom: 1px solid var(--gray-100);
}

.card-header h2 {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--gray-800);
}

.card-header h3 {
    font-size: 1rem;
    font-weight: 600;
    color: var(--gray-700);
}

/* ---- Grid layouts ---- */
.grid-2 {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1.5rem;
}

.grid-3 {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1.5rem;
}

.grid-4 {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 1rem;
}

/* ---- Stat Cards ---- */
.stat-card {
    background: var(--white);
    border-radius: var(--radius);
    padding: 1.25rem;
    border: 1px solid var(--gray-200);
    text-align: center;
}

.stat-card .stat-value {
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--primary);
    margin: 0.5rem 0;
}

.stat-card .stat-label {
    font-size: 0.85rem;
    color: var(--gray-500);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.stat-card.success .stat-value { color: var(--success); }
.stat-card.danger .stat-value { color: var(--danger); }
.stat-card.warning .stat-value { color: var(--warning); }
.stat-card.info .stat-value { color: var(--info); }

/* ---- Buttons ---- */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.6rem 1.2rem;
    border: none;
    border-radius: var(--radius);
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition);
    text-decoration: none;
}

.btn-primary {
    background: var(--primary);
    color: var(--white);
}

.btn-primary:hover {
    background: var(--primary-dark);
}

.btn-success {
    background: var(--success);
    color: var(--white);
}

.btn-success:hover {
    background: #047857;
}

.btn-danger {
    background: var(--danger);
    color: var(--white);
}

.btn-secondary {
    background: var(--gray-200);
    color: var(--gray-700);
}

.btn-secondary:hover {
    background: var(--gray-300);
}

.btn-sm {
    padding: 0.35rem 0.75rem;
    font-size: 0.8rem;
}

.btn-group {
    display: flex;
    gap: 0.5rem;
    flex-wrap: wrap;
}

/* ---- Forms ---- */
.form-group {
    margin-bottom: 1rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.35rem;
    font-weight: 500;
    font-size: 0.9rem;
    color: var(--gray-700);
}

.form-control {
    width: 100%;
    padding: 0.6rem 0.8rem;
    border: 1px solid var(--gray-300);
    border-radius: var(--radius);
    font-size: 0.9rem;
    transition: border-color var(--transition), box-shadow var(--transition);
    background: var(--white);
    color: var(--gray-800);
}

.form-control:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.15);
}

select.form-control {
    appearance: auto;
}

.form-row {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1rem;
}

.form-row-3 {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1rem;
}

/* ---- Tables ---- */
.table-container {
    overflow-x: auto;
    border-radius: var(--radius);
    border: 1px solid var(--gray-200);
}

table {
    width: 100%;
    border-collapse: collapse;
}

thead th {
    background: var(--gray-50);
    padding: 0.75rem 1rem;
    text-align: left;
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--gray-600);
    text-transform: uppercase;
    letter-spacing: 0.3px;
    border-bottom: 2px solid var(--gray-200);
}

tbody td {
    padding: 0.75rem 1rem;
    border-bottom: 1px solid var(--gray-100);
    font-size: 0.9rem;
}

tbody tr:hover {
    background: var(--gray-50);
}

/* ---- Charts ---- */
.chart-container {
    position: relative;
    width: 100%;
    height: 350px;
    margin: 1rem 0;
}

.chart-container canvas {
    width: 100% !important;
    height: 100% !important;
}

.chart-row {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1.5rem;
}

/* ---- Badges ---- */
.badge {
    display: inline-block;
    padding: 0.2rem 0.6rem;
    border-radius: 20px;
    font-size: 0.75rem;
    font-weight: 600;
}

.badge-primary { background: var(--primary-light); color: var(--primary-dark); }
.badge-success { background: var(--success-light); color: var(--success); }
.badge-danger { background: var(--danger-light); color: var(--danger); }
.badge-warning { background: var(--warning-light); color: var(--warning); }
.badge-info { background: var(--info-light); color: var(--info); }

/* ---- Alerts ---- */
.alert {
    padding: 1rem 1.25rem;
    border-radius: var(--radius);
    margin-bottom: 1rem;
    font-size: 0.9rem;
}

.alert-success {
    background: var(--success-light);
    color: var(--success);
    border: 1px solid #a7f3d0;
}

.alert-danger {
    background: var(--danger-light);
    color: var(--danger);
    border: 1px solid #fca5a5;
}

.alert-info {
    background: var(--info-light);
    color: var(--info);
    border: 1px solid #7dd3fc;
}

/* ---- Page header ---- */
.page-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
}

.page-header h2 {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--gray-900);
}

/* ---- Comparison table ---- */
.comparison-grid {
    display: grid;
    gap: 1.5rem;
}

.comparison-item {
    background: var(--white);
    border: 2px solid var(--gray-200);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
    transition: border-color var(--transition);
}

.comparison-item.best {
    border-color: var(--success);
}

.comparison-item .strategy-name {
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--primary);
    margin-bottom: 0.5rem;
}

/* ---- Modal / Overlay ---- */
.modal-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,0.4);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 200;
}

.modal {
    background: var(--white);
    border-radius: var(--radius-lg);
    padding: 2rem;
    max-width: 600px;
    width: 90%;
    max-height: 80vh;
    overflow-y: auto;
    box-shadow: var(--shadow-lg);
}

/* ---- Loading ---- */
.loading {
    text-align: center;
    padding: 2rem;
    color: var(--gray-500);
}

.spinner {
    display: inline-block;
    width: 32px;
    height: 32px;
    border: 3px solid var(--gray-200);
    border-top-color: var(--primary);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* ---- Empty state ---- */
.empty-state {
    text-align: center;
    padding: 3rem 2rem;
    color: var(--gray-500);
}

.empty-state h3 {
    font-size: 1.2rem;
    margin-bottom: 0.5rem;
    color: var(--gray-600);
}

/* ---- Footer ---- */
.footer {
    background: var(--white);
    border-top: 1px solid var(--gray-200);
    padding: 1rem 2rem;
    text-align: center;
    color: var(--gray-500);
    font-size: 0.85rem;
}

/* ---- Tabs ---- */
.tabs {
    display: flex;
    border-bottom: 2px solid var(--gray-200);
    margin-bottom: 1.5rem;
    gap: 0;
}

.tab {
    padding: 0.75rem 1.5rem;
    cursor: pointer;
    font-weight: 500;
    color: var(--gray-500);
    border-bottom: 2px solid transparent;
    margin-bottom: -2px;
    transition: all var(--transition);
    background: none;
    border-top: none;
    border-left: none;
    border-right: none;
    font-size: 0.9rem;
}

.tab:hover {
    color: var(--primary);
}

.tab.active {
    color: var(--primary);
    border-bottom-color: var(--primary);
}

/* ---- Strategy selector ---- */
.strategy-cards {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.strategy-card {
    border: 2px solid var(--gray-200);
    border-radius: var(--radius);
    padding: 1rem;
    cursor: pointer;
    transition: all var(--transition);
    text-align: center;
}

.strategy-card:hover {
    border-color: var(--primary);
    background: var(--primary-light);
}

.strategy-card.selected {
    border-color: var(--primary);
    background: var(--primary-light);
}

.strategy-card h4 {
    font-size: 0.95rem;
    color: var(--gray-800);
    margin-bottom: 0.25rem;
}

.strategy-card p {
    font-size: 0.8rem;
    color: var(--gray-500);
}

/* ---- Responsive ---- */
@media (max-width: 1024px) {
    .grid-4 { grid-template-columns: repeat(2, 1fr); }
    .grid-3 { grid-template-columns: repeat(2, 1fr); }
    .strategy-cards { grid-template-columns: repeat(2, 1fr); }
    .chart-row { grid-template-columns: 1fr; }
}

@media (max-width: 768px) {
    .navbar {
        flex-direction: column;
        height: auto;
        padding: 1rem;
    }
    .nav-links {
        flex-wrap: wrap;
        justify-content: center;
    }
    .grid-2, .grid-3, .grid-4 {
        grid-template-columns: 1fr;
    }
    .form-row, .form-row-3 {
        grid-template-columns: 1fr;
    }
    .strategy-cards {
        grid-template-columns: 1fr;
    }
    .page-header {
        flex-direction: column;
        gap: 1rem;
        align-items: flex-start;
    }
}