/* CSS Variables */
:root {
    --primary-color: #6366f1;
    --primary-hover: #4f46e5;
    --primary-light: #e0e7ff;
    --success-color: #10b981;
    --success-hover: #059669;
    --secondary-color: #64748b;
    --secondary-hover: #475569;
    --background: #0f172a;
    --surface: #1e293b;
    --surface-light: #334155;
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --text-muted: #64748b;
    --border-color: #334155;
    --error-color: #ef4444;
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.3);
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 16px;
    --transition: all 0.2s ease;
}

/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
    background: var(--background);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
}

/* App Container */
.app-container {
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

/* Header */
.header {
    text-align: center;
    padding: 2rem 1rem;
    background: linear-gradient(135deg, var(--surface) 0%, var(--background) 100%);
    border-bottom: 1px solid var(--border-color);
}

.logo {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.75rem;
    margin-bottom: 0.5rem;
}

.logo-img {
    width: 48px;
    height: 48px;
    border-radius: var(--radius-sm);
}

.header h1 {
    font-size: 2rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--primary-color) 0%, #a855f7 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.tagline {
    color: var(--text-secondary);
    font-size: 1rem;
}

/* Main Content */
.main-content {
    flex: 1;
    max-width: 900px;
    margin: 0 auto;
    padding: 2rem 1rem;
    width: 100%;
}

/* Sections */
section {
    margin-bottom: 2rem;
}

section h3 {
    font-size: 1.25rem;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

section h4 {
    font-size: 1rem;
    margin-bottom: 0.75rem;
    color: var(--text-secondary);
}

/* Upload Area */
.upload-area {
    border: 2px dashed var(--border-color);
    border-radius: var(--radius-lg);
    padding: 3rem 2rem;
    text-align: center;
    background: var(--surface);
    transition: var(--transition);
    cursor: pointer;
}

.upload-area:hover,
.upload-area.dragover {
    border-color: var(--primary-color);
    background: rgba(99, 102, 241, 0.1);
}

.upload-icon {
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.upload-area h2 {
    font-size: 1.5rem;
    margin-bottom: 0.5rem;
}

.upload-area p {
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
}

.supported-formats {
    font-size: 0.875rem;
    color: var(--text-muted);
    margin-bottom: 1.5rem;
}

/* File Info */
.file-info {
    background: var(--surface);
    border-radius: var(--radius-md);
    padding: 1rem;
    margin-top: 1rem;
}

.file-details {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.file-icon {
    font-size: 2rem;
}

.file-text {
    flex: 1;
    display: flex;
    flex-direction: column;
}

.file-name {
    font-weight: 600;
    color: var(--text-primary);
}

.file-size {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.75rem 1.5rem;
    font-size: 1rem;
    font-weight: 600;
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: var(--transition);
    text-decoration: none;
}

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

.btn-primary:hover {
    background: var(--primary-hover);
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

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

.btn-success:hover {
    background: var(--success-hover);
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

.btn-secondary {
    background: var(--surface-light);
    color: var(--text-primary);
}

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

.btn-large {
    padding: 1rem 2rem;
    font-size: 1.125rem;
}

.btn-icon {
    background: none;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    padding: 0.5rem;
    border-radius: var(--radius-sm);
    transition: var(--transition);
    font-size: 1.25rem;
}

.btn-icon:hover {
    color: var(--error-color);
    background: rgba(239, 68, 68, 0.1);
}

.btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    transform: none;
}

/* Player Section */
.player-section {
    background: var(--surface);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
}

.player-section audio {
    width: 100%;
    margin-bottom: 1rem;
}

.waveform-container {
    background: var(--background);
    border-radius: var(--radius-md);
    padding: 1rem;
    overflow: hidden;
}

#waveformCanvas {
    width: 100%;
    height: 100px;
    display: block;
}

/* Settings Section */
.settings-section {
    background: var(--surface);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
}

.settings-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
}

.setting-item {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.setting-item label {
    font-weight: 600;
    color: var(--text-primary);
    font-size: 0.875rem;
}

.setting-item input[type="number"],
.setting-item input[type="text"],
.setting-item select {
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    background: var(--background);
    color: var(--text-primary);
    font-size: 1rem;
    transition: var(--transition);
}

.setting-item input:focus,
.setting-item select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.2);
}

.setting-item input[type="range"] {
    width: 100%;
    height: 8px;
    border-radius: 4px;
    background: var(--background);
    appearance: none;
    cursor: pointer;
}

.setting-item input[type="range"]::-webkit-slider-thumb {
    appearance: none;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: var(--primary-color);
    cursor: pointer;
    transition: var(--transition);
}

.setting-item input[type="range"]::-webkit-slider-thumb:hover {
    transform: scale(1.1);
}

.threshold-value {
    font-weight: 600;
    color: var(--primary-color);
}

.setting-hint {
    font-size: 0.75rem;
    color: var(--text-muted);
}

/* Convert Section */
.convert-section {
    text-align: center;
}

.btn-text,
.btn-loading {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.spinner {
    width: 20px;
    height: 20px;
    border: 2px solid rgba(255, 255, 255, 0.3);
    border-top-color: white;
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

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

/* Progress Section */
.progress-section {
    background: var(--surface);
    border-radius: var(--radius-lg);
    padding: 2rem;
}

.progress-container {
    text-align: center;
}

.progress-bar {
    height: 8px;
    background: var(--background);
    border-radius: 4px;
    overflow: hidden;
    margin-bottom: 1rem;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--primary-color), #a855f7);
    border-radius: 4px;
    transition: width 0.3s ease;
    width: 0%;
}

.progress-text {
    color: var(--text-secondary);
}

/* Results Section */
.results-section {
    background: var(--surface);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
}

.results-stats {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1rem;
    margin-bottom: 2rem;
}

.stat-item {
    text-align: center;
    padding: 1rem;
    background: var(--background);
    border-radius: var(--radius-md);
}

.stat-value {
    display: block;
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 0.25rem;
}

.stat-label {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

/* Piano Roll */
.piano-roll-container {
    margin-bottom: 2rem;
}

.piano-roll-wrapper {
    background: var(--background);
    border-radius: var(--radius-md);
    padding: 1rem;
    overflow-x: auto;
}

#pianoRollCanvas {
    display: block;
    min-width: 100%;
    height: 300px;
}

/* Download Section */
.download-section {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
}

/* Footer */
.footer {
    text-align: center;
    padding: 1.5rem;
    background: var(--surface);
    border-top: 1px solid var(--border-color);
    margin-top: auto;
}

.footer p {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

.footer a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 600;
    transition: var(--transition);
}

.footer a:hover {
    color: var(--primary-hover);
    text-decoration: underline;
}

/* Responsive Design */
@media (max-width: 768px) {
    .header h1 {
        font-size: 1.5rem;
    }

    .upload-area {
        padding: 2rem 1rem;
    }

    .upload-area h2 {
        font-size: 1.25rem;
    }

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

    .results-stats {
        grid-template-columns: 1fr;
    }

    .stat-item {
        padding: 0.75rem;
    }

    .stat-value {
        font-size: 1.5rem;
    }

    .btn-large {
        width: 100%;
        padding: 1rem;
    }

    .download-section {
        flex-direction: column;
    }

    .download-section .btn {
        width: 100%;
    }

    #pianoRollCanvas {
        height: 200px;
    }
}

@media (max-width: 480px) {
    .main-content {
        padding: 1rem;
    }

    .header {
        padding: 1.5rem 1rem;
    }

    .logo {
        flex-direction: column;
    }

    .upload-icon svg {
        width: 48px;
        height: 48px;
    }

    section {
        margin-bottom: 1.5rem;
    }

    .player-section,
    .settings-section,
    .results-section,
    .progress-section {
        padding: 1rem;
    }
}

/* Animations */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.fade-in {
    animation: fadeIn 0.3s ease forwards;
}

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

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

/* Scrollbar styling */
::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}

::-webkit-scrollbar-track {
    background: var(--background);
}

::-webkit-scrollbar-thumb {
    background: var(--surface-light);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--secondary-color);
}