/*
    Metronome - Forward-Thinking Design System
    Inspired by architectural modernism: form follows function,
    honest materials, and the beauty of precision engineering
*/

:root {
    /* Color Palette - Dark Mode (Default) */
    --primary-dark: #0a0a0f;
    --primary-surface: #16161d;
    --secondary-surface: #1e1e28;
    --tertiary-surface: #2a2a38;

    --accent-primary: #00e5ff;
    --accent-secondary: #b388ff;
    --accent-tertiary: #ff6b9d;

    --text-primary: #e8e8f0;
    --text-secondary: #9494a8;
    --text-tertiary: #5a5a6e;

    --pulse-glow: rgba(0, 229, 255, 0.4);
    --success: #00ffa3;
    --warning: #ffd600;

    /* Typography */
    --font-mono: 'SF Mono', 'Monaco', 'Inconsolata', 'Roboto Mono', monospace;
    --font-display: -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;

    /* Spacing */
    --space-unit: 8px;
    --radius: 4px;

    /* Transitions */
    --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-smooth: 300ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-elastic: 500ms cubic-bezier(0.68, -0.55, 0.265, 1.55);
}

/* Light Mode - System Preference */
@media (prefers-color-scheme: light) {
    :root {
        /* Light Mode Palette - Inverted with adjusted brightness */
        --primary-dark: #f5f5fa;
        --primary-surface: #ffffff;
        --secondary-surface: #f8f8fc;
        --tertiary-surface: #e8e8f0;

        /* Accent colors adjusted for light backgrounds */
        --accent-primary: #0099cc;
        --accent-secondary: #7c4dff;
        --accent-tertiary: #e91e63;

        /* Text colors inverted */
        --text-primary: #1a1a24;
        --text-secondary: #4a4a5e;
        --text-tertiary: #8a8a9e;

        /* Glow effects adjusted for light mode */
        --pulse-glow: rgba(0, 153, 204, 0.3);
        --success: #00c853;
        --warning: #ffa000;
    }
}

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

body {
    font-family: var(--font-display);
    background: var(--primary-dark);
    color: var(--text-primary);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: calc(var(--space-unit) * 3);
    overflow-x: hidden;
    transition: background var(--transition-smooth), color var(--transition-smooth);

    /* Subtle grain texture for depth */
    background-image:
        radial-gradient(circle at 20% 50%, rgba(0, 229, 255, 0.03) 0%, transparent 50%),
        radial-gradient(circle at 80% 80%, rgba(179, 136, 255, 0.03) 0%, transparent 50%);
}

/* Light mode adjustments for background gradients */
@media (prefers-color-scheme: light) {
    body {
        background-image:
            radial-gradient(circle at 20% 50%, rgba(0, 153, 204, 0.04) 0%, transparent 50%),
            radial-gradient(circle at 80% 80%, rgba(124, 77, 255, 0.04) 0%, transparent 50%);
    }
}

.container {
    width: 100%;
    max-width: 900px;
    display: grid;
    gap: calc(var(--space-unit) * 3);
    position: relative;
}

/* ========================================
   Pulse Ring - Visual Rhythm Indicator
   ======================================== */

.pulse-ring {
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 80vmin;
    height: 80vmin;
    border: 2px solid var(--tertiary-surface);
    border-radius: 50%;
    pointer-events: none;
    z-index: 0;
    transition: border-color var(--transition-fast);
}

.pulse-ring.pulse {
    animation: pulse 100ms ease-out;
}

.pulse-ring.downbeat {
    border-color: var(--accent-primary);
    box-shadow: 0 0 60px var(--pulse-glow), inset 0 0 60px var(--pulse-glow);
}

.pulse-ring.beat {
    border-color: var(--accent-secondary);
}

@keyframes pulse {
    0% {
        transform: translate(-50%, -50%) scale(1);
        opacity: 1;
    }
    100% {
        transform: translate(-50%, -50%) scale(1.05);
        opacity: 0.7;
    }
}

/* ========================================
   Control Panel
   ======================================== */

.control-panel {
    background: var(--primary-surface);
    border: 1px solid var(--tertiary-surface);
    padding: calc(var(--space-unit) * 4);
    display: grid;
    gap: calc(var(--space-unit) * 4);
    position: relative;
    z-index: 1;
    transition: background var(--transition-smooth), border-color var(--transition-smooth), box-shadow var(--transition-smooth);

    /* Geometric shadow for depth */
    box-shadow:
        0 1px 0 var(--tertiary-surface),
        0 4px 0 var(--secondary-surface),
        0 4px 40px rgba(0, 0, 0, 0.5);
}

/* Light mode shadow adjustment */
@media (prefers-color-scheme: light) {
    .control-panel {
        box-shadow:
            0 1px 0 var(--tertiary-surface),
            0 4px 0 var(--secondary-surface),
            0 4px 40px rgba(0, 0, 0, 0.08);
    }
}

/* ========================================
   BPM Section
   ======================================== */

.bpm-section {
    display: grid;
    gap: calc(var(--space-unit) * 3);
}

.bpm-display {
    display: flex;
    align-items: baseline;
    justify-content: center;
    gap: calc(var(--space-unit) * 2);
}

.bpm-input {
    font-family: var(--font-mono);
    font-size: clamp(4rem, 12vw, 8rem);
    font-weight: 300;
    background: transparent;
    border: none;
    color: var(--accent-primary);
    text-align: right;
    width: 5ch;
    padding: 0;
    letter-spacing: -0.02em;
    transition: color var(--transition-fast);
}

.bpm-input:focus {
    outline: none;
    color: var(--success);
}

/* Remove spinner arrows */
.bpm-input::-webkit-inner-spin-button,
.bpm-input::-webkit-outer-spin-button {
    -webkit-appearance: none;
    margin: 0;
}

.bpm-input[type=number] {
    -moz-appearance: textfield;
}

.bpm-label {
    font-family: var(--font-mono);
    font-size: 1.5rem;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.1em;
}

.bpm-slider-container {
    position: relative;
}

.bpm-slider {
    width: 100%;
    height: 4px;
    background: var(--secondary-surface);
    outline: none;
    border: none;
    appearance: none;
    cursor: pointer;
    position: relative;
}

.bpm-slider::-webkit-slider-thumb {
    appearance: none;
    width: 20px;
    height: 20px;
    background: var(--accent-primary);
    border: 2px solid var(--primary-dark);
    cursor: grab;
    transition: all var(--transition-fast);
    box-shadow: 0 0 20px rgba(0, 229, 255, 0.4);
}

.bpm-slider::-webkit-slider-thumb:hover {
    transform: scale(1.2);
    box-shadow: 0 0 30px rgba(0, 229, 255, 0.6);
}

.bpm-slider::-webkit-slider-thumb:active {
    cursor: grabbing;
    transform: scale(1.1);
}

.bpm-slider::-moz-range-thumb {
    width: 20px;
    height: 20px;
    background: var(--accent-primary);
    border: 2px solid var(--primary-dark);
    cursor: grab;
    transition: all var(--transition-fast);
    box-shadow: 0 0 20px rgba(0, 229, 255, 0.4);
}

.bpm-slider::-moz-range-thumb:hover {
    transform: scale(1.2);
    box-shadow: 0 0 30px rgba(0, 229, 255, 0.6);
}

.slider-markers {
    display: flex;
    justify-content: space-between;
    margin-top: calc(var(--space-unit));
    font-family: var(--font-mono);
    font-size: 0.75rem;
    color: var(--text-tertiary);
}

/* ========================================
   Tap Tempo
   ======================================== */

.tap-section {
    display: flex;
    justify-content: center;
}

.tap-button {
    font-family: var(--font-mono);
    font-size: 1rem;
    letter-spacing: 0.15em;
    padding: calc(var(--space-unit) * 2) calc(var(--space-unit) * 6);
    background: var(--secondary-surface);
    border: 1px solid var(--tertiary-surface);
    color: var(--text-primary);
    cursor: pointer;
    transition: all var(--transition-fast);
    position: relative;
    overflow: hidden;
}

.tap-button::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, var(--accent-primary), transparent);
    opacity: 0;
    transition: all var(--transition-smooth);
}

.tap-button:hover {
    border-color: var(--accent-primary);
    color: var(--accent-primary);
}

.tap-button:active {
    transform: scale(0.98);
    background: var(--tertiary-surface);
}

.tap-button:active::before {
    left: 100%;
    opacity: 0.3;
}

/* ========================================
   Playback Control
   ======================================== */

.playback-section {
    display: flex;
    justify-content: center;
    margin: calc(var(--space-unit) * 2) 0;
}

.play-button {
    width: 120px;
    height: 120px;
    border-radius: 50%;
    background: var(--secondary-surface);
    border: 2px solid var(--tertiary-surface);
    color: var(--text-primary);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-smooth);
    position: relative;
    overflow: hidden;
}

.play-button::before {
    content: '';
    position: absolute;
    inset: -2px;
    border-radius: 50%;
    padding: 2px;
    background: linear-gradient(135deg, var(--accent-primary), var(--accent-secondary));
    -webkit-mask: linear-gradient(#fff 0 0) content-box, linear-gradient(#fff 0 0);
    -webkit-mask-composite: xor;
    mask-composite: exclude;
    opacity: 0;
    transition: opacity var(--transition-smooth);
}

.play-button:hover::before {
    opacity: 1;
}

.play-button:hover {
    transform: scale(1.05);
    box-shadow: 0 0 40px rgba(0, 229, 255, 0.3);
}

.play-button:active {
    transform: scale(0.95);
}

.play-button.playing {
    background: var(--accent-primary);
    color: var(--primary-dark);
    border-color: var(--accent-primary);
    box-shadow: 0 0 40px var(--pulse-glow);
}

.play-icon,
.pause-icon {
    width: 40px;
    height: 40px;
    transition: all var(--transition-fast);
}

.hidden {
    display: none;
}

/* ========================================
   Rhythm Section
   ======================================== */

.rhythm-section {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: calc(var(--space-unit) * 2);
}

.time-signature,
.subdivision {
    display: grid;
    gap: calc(var(--space-unit));
}

.rhythm-section label {
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--text-secondary);
    font-family: var(--font-mono);
}

.rhythm-select {
    font-family: var(--font-mono);
    font-size: 1rem;
    padding: calc(var(--space-unit) * 1.5);
    background: var(--secondary-surface);
    border: 1px solid var(--tertiary-surface);
    color: var(--text-primary);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.rhythm-select:hover {
    border-color: var(--accent-primary);
}

.rhythm-select:focus {
    outline: none;
    border-color: var(--accent-primary);
    box-shadow: 0 0 0 1px var(--accent-primary);
}

/* ========================================
   Beat Indicators
   ======================================== */

.beat-indicators {
    display: flex;
    gap: calc(var(--space-unit) * 2);
    justify-content: center;
    padding: calc(var(--space-unit) * 2) 0;
}

.beat {
    width: 16px;
    height: 16px;
    background: var(--secondary-surface);
    border: 1px solid var(--tertiary-surface);
    transition: all var(--transition-fast);
}

.beat.active {
    background: var(--accent-primary);
    border-color: var(--accent-primary);
    box-shadow: 0 0 20px var(--pulse-glow);
}

.beat.downbeat {
    background: var(--accent-primary);
    border-color: var(--accent-primary);
    box-shadow: 0 0 30px var(--pulse-glow);
    transform: scale(1.2);
}

/* ========================================
   Presets
   ======================================== */

.presets-section {
    border-top: 1px solid var(--tertiary-surface);
    padding-top: calc(var(--space-unit) * 3);
    margin-top: calc(var(--space-unit) * 2);
}

.presets-header h3 {
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--text-secondary);
    font-family: var(--font-mono);
    margin-bottom: calc(var(--space-unit) * 2);
    font-weight: 400;
}

.presets-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
    gap: calc(var(--space-unit) * 1.5);
}

.preset-button {
    font-family: var(--font-display);
    padding: calc(var(--space-unit) * 2);
    background: var(--secondary-surface);
    border: 1px solid var(--tertiary-surface);
    color: var(--text-primary);
    cursor: pointer;
    transition: all var(--transition-fast);
    text-align: center;
    line-height: 1.4;
}

.preset-button span {
    display: block;
    font-family: var(--font-mono);
    color: var(--text-secondary);
    font-size: 0.875rem;
    margin-top: calc(var(--space-unit) * 0.5);
}

.preset-button:hover {
    border-color: var(--accent-primary);
    background: var(--tertiary-surface);
    transform: translateY(-2px);
}

.preset-button:active {
    transform: translateY(0);
}

/* ========================================
   Volume Section
   ======================================== */

.volume-section {
    display: grid;
    gap: calc(var(--space-unit));
}

.volume-section label {
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--text-secondary);
    font-family: var(--font-mono);
}

.volume-slider {
    width: 100%;
    height: 4px;
    background: var(--secondary-surface);
    outline: none;
    border: none;
    appearance: none;
    cursor: pointer;
}

.volume-slider::-webkit-slider-thumb {
    appearance: none;
    width: 16px;
    height: 16px;
    background: var(--accent-secondary);
    border: 2px solid var(--primary-dark);
    cursor: grab;
    transition: all var(--transition-fast);
}

.volume-slider::-webkit-slider-thumb:hover {
    transform: scale(1.2);
    box-shadow: 0 0 20px rgba(179, 136, 255, 0.4);
}

.volume-slider::-moz-range-thumb {
    width: 16px;
    height: 16px;
    background: var(--accent-secondary);
    border: 2px solid var(--primary-dark);
    cursor: grab;
    transition: all var(--transition-fast);
}

/* ========================================
   Sound Selection
   ======================================== */

.sound-section {
    display: grid;
    gap: calc(var(--space-unit));
}

.sound-section label {
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--text-secondary);
    font-family: var(--font-mono);
}

.sound-select {
    font-family: var(--font-mono);
    font-size: 1rem;
    padding: calc(var(--space-unit) * 1.5);
    background: var(--secondary-surface);
    border: 1px solid var(--tertiary-surface);
    color: var(--text-primary);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.sound-select:hover {
    border-color: var(--accent-secondary);
}

.sound-select:focus {
    outline: none;
    border-color: var(--accent-secondary);
    box-shadow: 0 0 0 1px var(--accent-secondary);
}

/* ========================================
   Info Panel
   ======================================== */

.info-panel {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: calc(var(--space-unit) * 2);
    position: relative;
    z-index: 1;
}

.info-item {
    background: var(--primary-surface);
    border: 1px solid var(--tertiary-surface);
    padding: calc(var(--space-unit) * 2);
    display: flex;
    flex-direction: column;
    gap: calc(var(--space-unit));
}

.info-label {
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--text-secondary);
    font-family: var(--font-mono);
}

.info-value {
    font-family: var(--font-mono);
    font-size: 2rem;
    color: var(--accent-primary);
}

/* ========================================
   Responsive Design
   ======================================== */

@media (max-width: 768px) {
    body {
        padding: calc(var(--space-unit) * 2);
    }

    .control-panel {
        padding: calc(var(--space-unit) * 3);
    }

    .bpm-input {
        font-size: 5rem;
    }

    .play-button {
        width: 100px;
        height: 100px;
    }

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

    .rhythm-section {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    .bpm-input {
        font-size: 4rem;
    }

    .play-button {
        width: 80px;
        height: 80px;
    }

    .play-icon,
    .pause-icon {
        width: 30px;
        height: 30px;
    }
}

/* ========================================
   Accessibility
   ======================================== */

@media (prefers-reduced-motion: reduce) {
    * {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* Focus styles for keyboard navigation */
*:focus-visible {
    outline: 2px solid var(--accent-primary);
    outline-offset: 2px;
}

/* ========================================
   Light Mode - Additional Refinements
   ======================================== */

@media (prefers-color-scheme: light) {
    /* Input elements get smooth transitions */
    input,
    select,
    button {
        transition: background var(--transition-smooth),
                    border-color var(--transition-smooth),
                    color var(--transition-smooth);
    }

    /* Info panel transitions */
    .info-item {
        transition: background var(--transition-smooth),
                    border-color var(--transition-smooth);
    }

    /* Adjust beat indicator borders for light mode */
    .beat {
        transition: background var(--transition-fast),
                    border-color var(--transition-fast),
                    box-shadow var(--transition-fast);
    }

    /* Ensure proper contrast in light mode */
    .bpm-input {
        color: var(--accent-primary);
    }

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

    /* Play button in light mode */
    .play-button.playing {
        background: var(--accent-primary);
        color: var(--primary-dark);
    }
}