/* ========================================
   UI Spacing Calculator — Premium Dark Theme
   ======================================== */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&family=JetBrains+Mono:wght@400;500&display=swap');

:root {
    --primary: #F97316;
    --primary-rgb: 249, 115, 22;
    --primary-hover: #EA580C;
    --primary-glow: rgba(249, 115, 22, 0.25);
    --accent: #22D3EE;
    --accent-glow: rgba(34, 211, 238, 0.2);
    --success: #10B981;

    --bg-deep: #0F0F14;
    --bg-base: #18181F;
    --bg-surface: #222230;
    --bg-elevated: #2E2E3E;
    --bg-glass: rgba(24, 24, 31, 0.85);

    --text-primary: #F4F4F8;
    --text-secondary: #A1A1B5;
    --text-muted: #6C6C82;

    --border: rgba(100, 100, 140, 0.15);
    --border-hover: rgba(100, 100, 140, 0.3);

    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-full: 9999px;

    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.4);

    --font-sans: 'Inter', system-ui, -apple-system, sans-serif;
    --font-mono: 'JetBrains Mono', 'Fira Code', monospace;

    --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-base: 250ms cubic-bezier(0.4, 0, 0.2, 1);
}

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

html {
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
}

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

.app {
    max-width: 800px;
    margin: 0 auto;
    padding: 0 20px 60px;
}

/* ── Header ── */
.header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 20px 0 28px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-weight: 700;
    font-size: 1.15rem;
}

.logo-icon {
    width: 36px;
    height: 36px;
    background: linear-gradient(135deg, var(--primary), #FBBF24);
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.1rem;
    box-shadow: 0 2px 10px var(--primary-glow);
}

.header-actions {
    display: flex;
    gap: 8px;
}

/* ── Buttons ── */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 7px 14px;
    border-radius: var(--radius-sm);
    font-family: var(--font-sans);
    font-size: 0.8rem;
    font-weight: 500;
    border: 1px solid var(--border);
    background: var(--bg-surface);
    color: var(--text-primary);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.btn:hover {
    background: var(--bg-elevated);
    border-color: var(--border-hover);
    transform: translateY(-1px);
}

.btn:active {
    transform: translateY(0);
}

.btn-icon {
    padding: 7px;
    width: 34px;
    height: 34px;
    display: flex;
    align-items: center;
    justify-content: center;
}

/* ── Controls Card ── */
.controls-card {
    background: var(--bg-base);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 24px;
    margin-bottom: 24px;
}

.section-title {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 16px;
    color: var(--text-primary);
}

.controls-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: 16px;
    margin-bottom: 16px;
}

.control-group.full-width {
    grid-column: 1 / -1;
}

.control-label {
    display: block;
    font-size: 0.75rem;
    font-weight: 500;
    color: var(--text-muted);
    margin-bottom: 6px;
    text-transform: uppercase;
    letter-spacing: 0.04em;
}

.control-row {
    display: flex;
    align-items: center;
    gap: 6px;
}

.control-suffix {
    font-size: 0.8rem;
    color: var(--text-muted);
}

.control-input,
.control-select {
    width: 100%;
    padding: 8px 12px;
    font-family: var(--font-sans);
    font-size: 0.85rem;
    color: var(--text-primary);
    background: var(--bg-surface);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    outline: none;
    transition: border-color var(--transition-fast);
}

.control-input:focus,
.control-select:focus {
    border-color: var(--primary);
}

.hint {
    font-weight: 400;
    text-transform: none;
    letter-spacing: normal;
    color: var(--text-muted);
}

/* ── Presets ── */
.presets {
    display: flex;
    align-items: center;
    gap: 6px;
    flex-wrap: wrap;
}

.preset-label {
    font-size: 0.75rem;
    color: var(--text-muted);
    font-weight: 500;
}

.preset-btn {
    padding: 4px 10px;
    font-size: 0.72rem;
    font-weight: 500;
    font-family: var(--font-sans);
    border-radius: var(--radius-full);
    border: 1px solid var(--border);
    background: var(--bg-surface);
    color: var(--text-secondary);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.preset-btn:hover {
    border-color: var(--primary);
    color: var(--primary);
}

.preset-btn.active {
    background: rgba(249, 115, 22, 0.12);
    border-color: rgba(249, 115, 22, 0.4);
    color: var(--primary);
}

/* ── Scale Table ── */
.scale-section {
    margin-bottom: 24px;
}

.scale-table {
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.scale-row {
    display: grid;
    grid-template-columns: 100px 80px 1fr 60px;
    align-items: center;
    gap: 16px;
    padding: 10px 16px;
    background: var(--bg-base);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    transition: all var(--transition-fast);
}

.scale-row:hover {
    border-color: var(--border-hover);
    background: var(--bg-surface);
}

.scale-row.header {
    background: transparent;
    border: none;
    padding: 6px 16px;
}

.scale-name {
    font-weight: 600;
    font-size: 0.82rem;
    color: var(--primary);
}

.scale-value {
    font-family: var(--font-mono);
    font-size: 0.82rem;
    color: var(--text-secondary);
}

.scale-bar {
    height: 8px;
    border-radius: var(--radius-full);
    background: linear-gradient(90deg, var(--primary), var(--accent));
    transition: width 0.4s ease;
    min-width: 2px;
}

.scale-rem {
    font-family: var(--font-mono);
    font-size: 0.72rem;
    color: var(--text-muted);
    text-align: right;
}

.header-cell {
    font-size: 0.68rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-muted);
}

/* ── Visual Preview ── */
.preview-section {
    margin-bottom: 24px;
}

.preview-area {
    background: var(--bg-base);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: 24px;
    display: flex;
    flex-direction: column;
    gap: 4px;
}

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

.preview-label {
    width: 80px;
    text-align: right;
    font-size: 0.7rem;
    color: var(--text-muted);
    font-family: var(--font-mono);
    white-space: nowrap;
}

.preview-box {
    height: 24px;
    border-radius: 3px;
    background: linear-gradient(135deg, rgba(249, 115, 22, 0.3), rgba(34, 211, 238, 0.2));
    border: 1px solid rgba(249, 115, 22, 0.2);
    transition: width 0.4s ease;
}

/* ── Code Output ── */
.code-section {
    margin-bottom: 24px;
}

.code-tabs {
    display: flex;
    gap: 2px;
    margin-bottom: 0;
    overflow-x: auto;
}

.code-tab {
    padding: 8px 14px;
    font-family: var(--font-sans);
    font-size: 0.75rem;
    font-weight: 500;
    border: 1px solid var(--border);
    border-bottom: none;
    border-radius: var(--radius-sm) var(--radius-sm) 0 0;
    background: var(--bg-surface);
    color: var(--text-muted);
    cursor: pointer;
    transition: all var(--transition-fast);
    white-space: nowrap;
}

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

.code-tab.active {
    background: var(--bg-base);
    color: var(--primary);
    border-color: var(--border);
}

.code-output {
    background: var(--bg-base);
    border: 1px solid var(--border);
    border-radius: 0 var(--radius-md) var(--radius-md) var(--radius-md);
    padding: 20px;
    overflow-x: auto;
    margin: 0;
    position: relative;
}

.code-output code {
    font-family: var(--font-mono);
    font-size: 0.8rem;
    line-height: 1.7;
    color: var(--text-secondary);
    white-space: pre;
}

/* ── Toast ── */
.toast-container {
    position: fixed;
    bottom: 20px;
    right: 20px;
    z-index: 2000;
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.toast {
    padding: 12px 16px;
    background: var(--bg-glass);
    backdrop-filter: blur(16px);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-md);
    font-size: 0.85rem;
    color: var(--text-primary);
    animation: toast-in 0.3s ease-out;
    max-width: 340px;
}

.toast.success {
    border-left: 3px solid var(--success);
}

@keyframes toast-in {
    from {
        opacity: 0;
        transform: translateX(40px);
    }

    to {
        opacity: 1;
        transform: translateX(0);
    }
}

/* ── Responsive ── */
@media (max-width: 600px) {
    .app {
        padding: 0 12px 40px;
    }

    .logo span {
        display: none;
    }

    .controls-grid {
        grid-template-columns: 1fr;
    }

    .scale-row {
        grid-template-columns: 80px 60px 1fr 44px;
        gap: 8px;
        padding: 8px 10px;
    }

    .preview-label {
        width: 60px;
    }
}

/* ── Animation ── */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(8px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.controls-card,
.scale-section,
.preview-section,
.code-section {
    animation: fadeIn 0.4s ease-out;
}