/*
 * APEX Premium UI Design System
 * Clean, professional SaaS design like Anthropic/Netflix
 * Supports dark (default) and light themes
 */

/* ========================================
   CSS Custom Properties (Design Tokens)
   ======================================== */

:root {
    /* Brand Colors */
    --color-primary: #a855f7;
    --color-primary-hover: #9333ea;
    --color-primary-light: rgba(168, 85, 247, 0.15);
    --color-accent: #10b981;
    --color-accent-hover: #059669;
    --color-warning: #f59e0b;
    --color-error: #ef4444;

    /* Typography */
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-mono: 'JetBrains Mono', 'Fira Code', monospace;

    /* Font Sizes */
    --text-xs: 0.75rem;
    --text-sm: 0.875rem;
    --text-base: 1rem;
    --text-lg: 1.125rem;
    --text-xl: 1.25rem;
    --text-2xl: 1.5rem;
    --text-3xl: 1.875rem;
    --text-4xl: 2.25rem;
    --text-5xl: 3rem;

    /* Spacing */
    --space-1: 0.25rem;
    --space-2: 0.5rem;
    --space-3: 0.75rem;
    --space-4: 1rem;
    --space-5: 1.25rem;
    --space-6: 1.5rem;
    --space-8: 2rem;
    --space-10: 2.5rem;
    --space-12: 3rem;
    --space-16: 4rem;
    --space-20: 5rem;

    /* Border Radius */
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 16px;
    --radius-xl: 24px;
    --radius-full: 9999px;

    /* Shadows */
    --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
    --shadow-md: 0 4px 6px rgba(0,0,0,0.1);
    --shadow-lg: 0 10px 15px rgba(0,0,0,0.1);
    --shadow-xl: 0 20px 25px rgba(0,0,0,0.15);

    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 200ms ease;
    --transition-slow: 300ms ease;

    /* Z-Index Scale */
    --z-dropdown: 100;
    --z-sticky: 200;
    --z-fixed: 300;
    --z-modal-backdrop: 400;
    --z-modal: 500;
    --z-tooltip: 600;
}

/* Dark Theme (Default) */
[data-theme="dark"], :root {
    --bg-primary: #0a0a1a;
    --bg-secondary: #12121f;
    --bg-tertiary: #1a1a2e;
    --bg-card: rgba(255, 255, 255, 0.03);
    --bg-card-hover: rgba(255, 255, 255, 0.06);
    --bg-elevated: rgba(255, 255, 255, 0.05);

    --text-primary: #ffffff;
    --text-secondary: #a1a1aa;
    --text-tertiary: #71717a;
    --text-muted: #52525b;

    --border-color: rgba(255, 255, 255, 0.1);
    --border-color-strong: rgba(255, 255, 255, 0.2);

    --glow-primary: 0 0 30px rgba(168, 85, 247, 0.3);
    --glow-accent: 0 0 30px rgba(16, 185, 129, 0.3);
}

/* Light Theme */
[data-theme="light"] {
    --bg-primary: #ffffff;
    --bg-secondary: #f8fafc;
    --bg-tertiary: #f1f5f9;
    --bg-card: rgba(0, 0, 0, 0.02);
    --bg-card-hover: rgba(0, 0, 0, 0.04);
    --bg-elevated: #ffffff;

    --text-primary: #0f172a;
    --text-secondary: #475569;
    --text-tertiary: #64748b;
    --text-muted: #94a3b8;

    --border-color: rgba(0, 0, 0, 0.1);
    --border-color-strong: rgba(0, 0, 0, 0.2);

    --glow-primary: 0 0 30px rgba(168, 85, 247, 0.15);
    --glow-accent: 0 0 30px rgba(16, 185, 129, 0.15);
}

/* ========================================
   Base Styles
   ======================================== */

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

body.premium-ui {
    font-family: var(--font-sans);
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* ========================================
   Layout Components
   ======================================== */

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--space-6);
}

.container-sm { max-width: 640px; }
.container-md { max-width: 768px; }
.container-lg { max-width: 1024px; }
.container-xl { max-width: 1280px; }

.section {
    padding: var(--space-16) 0;
}

.section-sm { padding: var(--space-10) 0; }
.section-lg { padding: var(--space-20) 0; }

/* ========================================
   Typography
   ======================================== */

.heading-1 {
    font-size: var(--text-5xl);
    font-weight: 700;
    line-height: 1.1;
    letter-spacing: -0.02em;
}

.heading-2 {
    font-size: var(--text-4xl);
    font-weight: 700;
    line-height: 1.2;
    letter-spacing: -0.01em;
}

.heading-3 {
    font-size: var(--text-3xl);
    font-weight: 600;
    line-height: 1.3;
}

.heading-4 {
    font-size: var(--text-2xl);
    font-weight: 600;
    line-height: 1.4;
}

.text-lg { font-size: var(--text-lg); }
.text-sm { font-size: var(--text-sm); }
.text-xs { font-size: var(--text-xs); }

.text-secondary { color: var(--text-secondary); }
.text-tertiary { color: var(--text-tertiary); }
.text-muted { color: var(--text-muted); }
.text-primary-color { color: var(--color-primary); }
.text-accent { color: var(--color-accent); }

.text-center { text-align: center; }
.text-right { text-align: right; }

/* ========================================
   Buttons
   ======================================== */

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-2);
    padding: var(--space-3) var(--space-6);
    font-family: var(--font-sans);
    font-size: var(--text-base);
    font-weight: 600;
    line-height: 1.5;
    text-decoration: none;
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-base);
    white-space: nowrap;
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

/* Primary Button */
.btn-primary {
    background: linear-gradient(135deg, var(--color-primary), #ec4899);
    color: white;
    box-shadow: var(--shadow-md);
}

.btn-primary:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg), var(--glow-primary);
}

.btn-primary:active:not(:disabled) {
    transform: translateY(0);
}

/* Secondary Button */
.btn-secondary {
    background: var(--bg-elevated);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

.btn-secondary:hover:not(:disabled) {
    background: var(--bg-card-hover);
    border-color: var(--border-color-strong);
}

/* Ghost Button */
.btn-ghost {
    background: transparent;
    color: var(--text-secondary);
}

.btn-ghost:hover:not(:disabled) {
    background: var(--bg-card);
    color: var(--text-primary);
}

/* Accent Button */
.btn-accent {
    background: linear-gradient(135deg, var(--color-accent), #059669);
    color: white;
}

.btn-accent:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg), var(--glow-accent);
}

/* Button Sizes */
.btn-sm {
    padding: var(--space-2) var(--space-4);
    font-size: var(--text-sm);
}

.btn-lg {
    padding: var(--space-4) var(--space-8);
    font-size: var(--text-lg);
}

.btn-xl {
    padding: var(--space-5) var(--space-10);
    font-size: var(--text-xl);
}

.btn-full { width: 100%; }

/* ========================================
   Cards
   ======================================== */

.card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: var(--space-6);
    transition: all var(--transition-base);
}

.card:hover {
    background: var(--bg-card-hover);
}

.card-elevated {
    background: var(--bg-elevated);
    box-shadow: var(--shadow-lg);
}

/* Highlighted Card (for "Most Popular") */
.card-highlighted {
    background: var(--bg-card);
    border: 2px solid var(--color-primary);
    box-shadow: var(--glow-primary);
    position: relative;
    transform: scale(1.02);
}

.card-highlighted::before {
    content: '';
    position: absolute;
    inset: -2px;
    border-radius: inherit;
    background: linear-gradient(135deg, var(--color-primary), #ec4899);
    z-index: -1;
    opacity: 0.2;
}

/* ========================================
   Pricing Cards
   ======================================== */

.pricing-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--space-6);
    align-items: start;
}

@media (max-width: 900px) {
    .pricing-grid {
        grid-template-columns: 1fr;
        max-width: 400px;
        margin: 0 auto;
    }

    .card-highlighted {
        transform: none;
        order: -1;
    }
}

.pricing-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
    padding: var(--space-8);
    text-align: center;
    transition: all var(--transition-base);
    position: relative;
}

.pricing-card.popular {
    border: 2px solid var(--color-primary);
    box-shadow: var(--glow-primary);
    transform: scale(1.05);
}

@media (max-width: 900px) {
    .pricing-card.popular {
        transform: none;
    }
}

.pricing-card-header {
    margin-bottom: var(--space-6);
}

.pricing-tier-name {
    font-size: var(--text-xl);
    font-weight: 600;
    color: var(--text-secondary);
    margin-bottom: var(--space-2);
}

.pricing-card.popular .pricing-tier-name {
    color: var(--color-primary);
}

.pricing-price {
    font-size: var(--text-5xl);
    font-weight: 700;
    color: var(--text-primary);
    line-height: 1;
}

.pricing-price-currency {
    font-size: var(--text-2xl);
    vertical-align: super;
}

.pricing-price-period {
    font-size: var(--text-base);
    font-weight: 400;
    color: var(--text-tertiary);
}

.pricing-description {
    font-size: var(--text-sm);
    color: var(--text-tertiary);
    margin-top: var(--space-2);
}

.pricing-features {
    list-style: none;
    text-align: left;
    margin: var(--space-6) 0;
}

.pricing-feature {
    display: flex;
    align-items: flex-start;
    gap: var(--space-3);
    padding: var(--space-3) 0;
    color: var(--text-secondary);
    font-size: var(--text-sm);
}

.pricing-feature-icon {
    flex-shrink: 0;
    width: 20px;
    height: 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: var(--radius-full);
    font-size: 12px;
}

.pricing-feature-icon.check {
    background: rgba(16, 185, 129, 0.15);
    color: var(--color-accent);
}

.pricing-feature-icon.x {
    background: rgba(239, 68, 68, 0.15);
    color: var(--color-error);
}

/* ========================================
   Badge Component
   ======================================== */

.badge {
    display: inline-flex;
    align-items: center;
    gap: var(--space-1);
    padding: var(--space-1) var(--space-3);
    font-size: var(--text-xs);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    border-radius: var(--radius-full);
}

.badge-primary {
    background: var(--color-primary-light);
    color: var(--color-primary);
}

.badge-accent {
    background: rgba(16, 185, 129, 0.15);
    color: var(--color-accent);
}

.badge-warning {
    background: rgba(245, 158, 11, 0.15);
    color: var(--color-warning);
}

/* Popular Badge for Pricing */
.badge-popular {
    position: absolute;
    top: -12px;
    left: 50%;
    transform: translateX(-50%);
    background: linear-gradient(135deg, var(--color-primary), #ec4899);
    color: white;
    padding: var(--space-2) var(--space-4);
    font-size: var(--text-xs);
    font-weight: 700;
    border-radius: var(--radius-full);
    box-shadow: var(--shadow-md);
}

/* ========================================
   Progress Steps
   ======================================== */

.progress-steps {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-2);
    margin-bottom: var(--space-8);
}

.progress-step {
    display: flex;
    align-items: center;
    gap: var(--space-2);
}

.progress-step-number {
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: var(--radius-full);
    font-size: var(--text-sm);
    font-weight: 600;
    background: var(--bg-tertiary);
    color: var(--text-tertiary);
    transition: all var(--transition-base);
}

.progress-step.active .progress-step-number {
    background: var(--color-primary);
    color: white;
}

.progress-step.completed .progress-step-number {
    background: var(--color-accent);
    color: white;
}

.progress-step-label {
    font-size: var(--text-sm);
    color: var(--text-tertiary);
    display: none;
}

@media (min-width: 640px) {
    .progress-step-label {
        display: block;
    }
}

.progress-step.active .progress-step-label {
    color: var(--text-primary);
}

.progress-step-line {
    width: 60px;
    height: 2px;
    background: var(--border-color);
}

.progress-step.completed + .progress-step .progress-step-line,
.progress-step.completed .progress-step-line {
    background: var(--color-accent);
}

/* ========================================
   Form Elements
   ======================================== */

.form-group {
    margin-bottom: var(--space-4);
}

.form-label {
    display: block;
    font-size: var(--text-sm);
    font-weight: 500;
    color: var(--text-secondary);
    margin-bottom: var(--space-2);
}

.form-input {
    width: 100%;
    padding: var(--space-3) var(--space-4);
    font-family: var(--font-sans);
    font-size: var(--text-base);
    color: var(--text-primary);
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    transition: all var(--transition-base);
}

.form-input:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px var(--color-primary-light);
}

.form-input::placeholder {
    color: var(--text-muted);
}

.form-input-mono {
    font-family: var(--font-mono);
    font-size: var(--text-sm);
}

/* ========================================
   Selection Cards (Payment Options)
   ======================================== */

.selection-cards {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-4);
}

@media (max-width: 480px) {
    .selection-cards {
        grid-template-columns: 1fr;
    }
}

.selection-card {
    background: var(--bg-card);
    border: 2px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: var(--space-5);
    cursor: pointer;
    transition: all var(--transition-base);
    text-align: center;
}

.selection-card:hover {
    border-color: var(--border-color-strong);
    background: var(--bg-card-hover);
}

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

.selection-card-icon {
    font-size: var(--text-3xl);
    margin-bottom: var(--space-2);
}

.selection-card-title {
    font-size: var(--text-lg);
    font-weight: 600;
    color: var(--text-primary);
}

.selection-card-subtitle {
    font-size: var(--text-sm);
    color: var(--text-tertiary);
}

/* ========================================
   Feature Comparison Table
   ======================================== */

.comparison-table {
    width: 100%;
    border-collapse: collapse;
    margin: var(--space-8) 0;
}

.comparison-table th,
.comparison-table td {
    padding: var(--space-4);
    text-align: left;
    border-bottom: 1px solid var(--border-color);
}

.comparison-table th {
    font-size: var(--text-sm);
    font-weight: 600;
    color: var(--text-tertiary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.comparison-table td {
    font-size: var(--text-sm);
    color: var(--text-secondary);
}

.comparison-table tbody tr:hover {
    background: var(--bg-card);
}

.comparison-table .feature-name {
    font-weight: 500;
    color: var(--text-primary);
}

.comparison-check {
    color: var(--color-accent);
    font-size: var(--text-lg);
}

.comparison-x {
    color: var(--text-muted);
    font-size: var(--text-lg);
}

@media (max-width: 768px) {
    .comparison-table {
        display: block;
        overflow-x: auto;
    }
}

/* ========================================
   FAQ Accordion
   ======================================== */

.faq-list {
    max-width: 768px;
    margin: 0 auto;
}

.faq-item {
    border-bottom: 1px solid var(--border-color);
}

.faq-question {
    width: 100%;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--space-5) 0;
    background: none;
    border: none;
    font-family: var(--font-sans);
    font-size: var(--text-base);
    font-weight: 500;
    color: var(--text-primary);
    text-align: left;
    cursor: pointer;
    transition: color var(--transition-base);
}

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

.faq-icon {
    font-size: var(--text-xl);
    color: var(--text-tertiary);
    transition: transform var(--transition-base);
}

.faq-item.open .faq-icon {
    transform: rotate(45deg);
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height var(--transition-slow);
}

.faq-item.open .faq-answer {
    max-height: 500px;
}

.faq-answer-content {
    padding-bottom: var(--space-5);
    font-size: var(--text-sm);
    color: var(--text-secondary);
    line-height: 1.7;
}

/* ========================================
   Dashboard Stats
   ======================================== */

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--space-4);
}

.stat-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: var(--space-5);
}

.stat-label {
    font-size: var(--text-sm);
    color: var(--text-tertiary);
    margin-bottom: var(--space-1);
}

.stat-value {
    font-size: var(--text-3xl);
    font-weight: 700;
    color: var(--text-primary);
}

.stat-value.accent { color: var(--color-accent); }
.stat-value.primary { color: var(--color-primary); }

.stat-change {
    font-size: var(--text-sm);
    margin-top: var(--space-1);
}

.stat-change.positive { color: var(--color-accent); }
.stat-change.negative { color: var(--color-error); }

/* ========================================
   Toast/Alert Messages
   ======================================== */

.toast {
    position: fixed;
    bottom: var(--space-6);
    right: var(--space-6);
    padding: var(--space-4) var(--space-6);
    background: var(--bg-elevated);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-xl);
    font-size: var(--text-sm);
    z-index: var(--z-tooltip);
    animation: slideIn var(--transition-base);
}

.toast-success {
    border-color: var(--color-accent);
    background: rgba(16, 185, 129, 0.1);
}

.toast-error {
    border-color: var(--color-error);
    background: rgba(239, 68, 68, 0.1);
}

@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* ========================================
   Modal
   ======================================== */

.modal-backdrop {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.8);
    backdrop-filter: blur(4px);
    z-index: var(--z-modal-backdrop);
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-base);
}

.modal-backdrop.active {
    opacity: 1;
    visibility: visible;
}

.modal {
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%) scale(0.95);
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
    padding: var(--space-8);
    max-width: 480px;
    width: 90%;
    max-height: 90vh;
    overflow-y: auto;
    z-index: var(--z-modal);
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-base);
}

.modal.active {
    opacity: 1;
    visibility: visible;
    transform: translate(-50%, -50%) scale(1);
}

.modal-close {
    position: absolute;
    top: var(--space-4);
    right: var(--space-4);
    background: none;
    border: none;
    font-size: var(--text-2xl);
    color: var(--text-tertiary);
    cursor: pointer;
    transition: color var(--transition-base);
}

.modal-close:hover {
    color: var(--text-primary);
}

.modal-title {
    font-size: var(--text-2xl);
    font-weight: 600;
    margin-bottom: var(--space-4);
}

/* ========================================
   Theme Toggle
   ======================================== */

.theme-toggle {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-full);
    padding: var(--space-1);
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: var(--space-1);
}

.theme-toggle-option {
    padding: var(--space-2) var(--space-3);
    border-radius: var(--radius-full);
    font-size: var(--text-sm);
    color: var(--text-tertiary);
    transition: all var(--transition-base);
}

.theme-toggle-option.active {
    background: var(--color-primary);
    color: white;
}

/* ========================================
   Copy Button
   ======================================== */

.copy-wrapper {
    display: flex;
    gap: var(--space-2);
    align-items: stretch;
}

.copy-input {
    flex: 1;
    padding: var(--space-3) var(--space-4);
    font-family: var(--font-mono);
    font-size: var(--text-sm);
    color: var(--color-accent);
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    overflow: hidden;
    text-overflow: ellipsis;
}

.copy-btn {
    padding: var(--space-3) var(--space-4);
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    color: var(--text-secondary);
    cursor: pointer;
    transition: all var(--transition-base);
    white-space: nowrap;
}

.copy-btn:hover {
    background: var(--bg-card-hover);
    color: var(--text-primary);
}

.copy-btn.copied {
    background: var(--color-accent);
    border-color: var(--color-accent);
    color: white;
}

/* ========================================
   Loading States
   ======================================== */

.spinner {
    width: 24px;
    height: 24px;
    border: 3px solid var(--border-color);
    border-top-color: var(--color-primary);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

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

.skeleton {
    background: linear-gradient(
        90deg,
        var(--bg-card) 25%,
        var(--bg-card-hover) 50%,
        var(--bg-card) 75%
    );
    background-size: 200% 100%;
    animation: shimmer 1.5s infinite;
    border-radius: var(--radius-md);
}

@keyframes shimmer {
    0% { background-position: 200% 0; }
    100% { background-position: -200% 0; }
}

/* ========================================
   Utility Classes
   ======================================== */

.flex { display: flex; }
.flex-col { flex-direction: column; }
.items-center { align-items: center; }
.justify-center { justify-content: center; }
.justify-between { justify-content: space-between; }
.gap-2 { gap: var(--space-2); }
.gap-4 { gap: var(--space-4); }
.gap-6 { gap: var(--space-6); }

.mt-2 { margin-top: var(--space-2); }
.mt-4 { margin-top: var(--space-4); }
.mt-6 { margin-top: var(--space-6); }
.mt-8 { margin-top: var(--space-8); }
.mb-2 { margin-bottom: var(--space-2); }
.mb-4 { margin-bottom: var(--space-4); }
.mb-6 { margin-bottom: var(--space-6); }
.mb-8 { margin-bottom: var(--space-8); }

.hidden { display: none !important; }
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}