/* ============================================
   API Rate Limit Planner — Design System
   ============================================ */
:root {
    --bg-primary: #0F0F1A;
    --bg-secondary: #1A1A2E;
    --bg-card: rgba(26, 26, 46, 0.85);
    --border-glass: rgba(255, 255, 255, 0.08);
    --text-primary: #E8E8F0;
    --text-secondary: #A29BFE;
    --text-muted: #6C6C8A;
    --accent: #6C5CE7;
    --accent-glow: rgba(108, 92, 231, 0.3);
    --teal: #00CEC9;
    --success: #4ADE80;
    --error: #F87171;
    --warning: #FBBF24;
    --radius: 10px;
    --radius-sm: 6px;
    --transition: 0.25s cubic-bezier(0.4, 0, 0.2, 1);
    --font: 'Inter', -apple-system, sans-serif;
}

[data-theme="light"] {
    --bg-primary: #F5F3FF;
    --bg-secondary: #FFFFFF;
    --bg-card: rgba(255, 255, 255, 0.9);
    --border-glass: rgba(0, 0, 0, 0.08);
    --text-primary: #1A1A2E;
    --text-secondary: #6C5CE7;
    --text-muted: #9B9BC0;
}

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

body {
    font-family: var(--font);
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    transition: background var(--transition);
}

body::before {
    content: '';
    position: fixed;
    inset: 0;
    background: radial-gradient(ellipse 600px 400px at 20% 20%, rgba(108, 92, 231, 0.06) 0%, transparent 70%),
        radial-gradient(ellipse 400px 300px at 80% 80%, rgba(0, 206, 201, 0.04) 0%, transparent 70%);
    pointer-events: none;
    z-index: -1;
}

.app {
    max-width: 960px;
    margin: 0 auto;
    padding: 0 16px 40px;
}

.header {
    padding: 16px 0 12px;
}

.header-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.logo {
    display: flex;
    align-items: center;
    gap: 12px;
}

.logo-icon {
    font-size: 1.5rem;
    width: 42px;
    height: 42px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, var(--accent), var(--teal));
    border-radius: var(--radius);
    box-shadow: 0 4px 16px var(--accent-glow);
}

.logo h1 {
    font-size: 1.1rem;
    font-weight: 700;
}

.tagline {
    font-size: 0.66rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.04em;
}

.icon-btn {
    width: 36px;
    height: 36px;
    border: none;
    background: rgba(26, 26, 46, 0.6);
    border: 1px solid var(--border-glass);
    border-radius: var(--radius-sm);
    color: var(--text-secondary);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition);
}

.icon-btn:hover {
    color: var(--accent);
}

.icon {
    width: 18px;
    height: 18px;
}

.moon-icon {
    display: none;
}

[data-theme="light"] .sun-icon {
    display: none;
}

[data-theme="light"] .moon-icon {
    display: block;
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: 5px;
    padding: 10px 20px;
    border: none;
    border-radius: var(--radius-sm);
    font-family: var(--font);
    font-size: 0.84rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition);
}

.btn-primary {
    background: linear-gradient(135deg, var(--accent), var(--teal));
    color: #fff;
    box-shadow: 0 2px 12px var(--accent-glow);
}

.btn-primary:hover {
    transform: translateY(-1px);
}

.btn-secondary {
    background: rgba(26, 26, 46, 0.6);
    border: 1px solid var(--border-glass);
    color: var(--text-secondary);
}

.btn-sm {
    padding: 6px 12px;
    font-size: 0.76rem;
}

.section {
    margin-bottom: 24px;
}

.section h2 {
    font-size: 0.92rem;
    font-weight: 700;
    margin-bottom: 10px;
}

/* Config Grid */
.config-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 10px;
}

.config-card {
    padding: 12px;
    background: var(--bg-card);
    border: 1px solid var(--border-glass);
    border-radius: var(--radius);
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.config-card label {
    font-size: 0.68rem;
    font-weight: 600;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.04em;
}

.config-card select,
.config-card input {
    padding: 8px 10px;
    background: var(--bg-secondary);
    border: 1px solid var(--border-glass);
    border-radius: var(--radius-sm);
    color: var(--text-primary);
    font-family: var(--font);
    font-size: 0.82rem;
}

.config-card select:focus,
.config-card input:focus {
    outline: none;
    border-color: var(--accent);
}

.unit {
    font-size: 0.64rem;
    color: var(--text-muted);
}

/* Stats */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(130px, 1fr));
    gap: 8px;
}

.stat-card {
    padding: 12px;
    background: var(--bg-card);
    border: 1px solid var(--border-glass);
    border-radius: var(--radius);
    text-align: center;
}

.stat-value {
    font-size: 1.2rem;
    font-weight: 800;
    color: var(--teal);
}

.stat-label {
    font-size: 0.64rem;
    color: var(--text-muted);
    text-transform: uppercase;
}

/* Timeline */
.timeline-container {
    background: var(--bg-card);
    border: 1px solid var(--border-glass);
    border-radius: var(--radius);
    padding: 12px;
    overflow-x: auto;
}

canvas {
    display: block;
    width: 100%;
}

/* Headers */
.headers-preview {
    padding: 14px;
    background: var(--bg-card);
    border: 1px solid var(--border-glass);
    border-radius: var(--radius);
    font-family: monospace;
    font-size: 0.78rem;
    color: var(--teal);
    line-height: 1.5;
    margin: 0;
}

/* Export */
.export-tabs {
    display: flex;
    gap: 4px;
    margin-bottom: 0;
}

.export-tab {
    padding: 8px 16px;
    border: none;
    background: rgba(26, 26, 46, 0.6);
    border: 1px solid var(--border-glass);
    border-bottom: none;
    border-radius: var(--radius-sm) var(--radius-sm) 0 0;
    color: var(--text-muted);
    font-family: var(--font);
    font-size: 0.78rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition);
}

.export-tab.active {
    background: var(--accent);
    color: #fff;
}

.export-panel {
    background: var(--bg-card);
    border: 1px solid var(--border-glass);
    border-radius: 0 var(--radius) var(--radius) var(--radius);
}

.export-code {
    padding: 14px;
    font-family: monospace;
    font-size: 0.74rem;
    color: var(--accent);
    line-height: 1.5;
    white-space: pre-wrap;
    max-height: 300px;
    overflow-y: auto;
    margin: 0;
}

.toast {
    position: fixed;
    bottom: 24px;
    left: 50%;
    transform: translateX(-50%) translateY(20px);
    padding: 10px 20px;
    background: var(--bg-card);
    border: 1px solid var(--border-glass);
    border-radius: var(--radius);
    color: var(--text-primary);
    font-size: 0.82rem;
    opacity: 0;
    transition: all 0.35s ease;
    z-index: 100;
    pointer-events: none;
}

.toast.show {
    opacity: 1;
    transform: translateX(-50%) translateY(0);
}

.hidden {
    display: none !important;
}

@media (max-width: 640px) {
    .config-grid {
        grid-template-columns: 1fr 1fr;
    }

    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}