/**
 * Audio Converter Tool - Optimized Styles v2.0
 * Modern UI with GPU-accelerated animations
 */

:root {
    /* Core Colors */
    --primary-color: #3b82f6;
    --primary-hover: #2563eb;
    --primary-light: rgba(59, 130, 246, 0.12);
    --primary-glow: rgba(59, 130, 246, 0.35);
    --secondary-color: #8b5cf6;
    --success-color: #10b981;
    --danger-color: #ef4444;
    --warning-color: #f59e0b;
    --info-color: #0ea5e9;
    
    /* Theme Colors */
    --dark-bg: #0f172a;
    --dark-card: #1e293b;
    --dark-text: #f1f5f9;
    --light-bg: #f8fafc;
    --light-card: #ffffff;
    --light-text: #1e293b;
    
    /* Enhanced Layout */
    --border-radius: 10px;
    --border-radius-sm: 6px;
    --border-radius-lg: 16px;
    --box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.08), 0 2px 4px -1px rgba(0, 0, 0, 0.04);
    --box-shadow-lg: 0 10px 25px -5px rgba(0, 0, 0, 0.1), 0 8px 10px -6px rgba(0, 0, 0, 0.05);
    
    /* GPU-Optimized Transitions */
    --transition-fast: 0.15s cubic-bezier(0.4, 0, 0.2, 1);
    --transition: 0.25s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    
    /* Glass Effect */
    --glass-blur: blur(12px);
    --glass-bg: rgba(255, 255, 255, 0.85);
    --glass-border: rgba(255, 255, 255, 0.3);
    
    /* Borders */
    --border-color: #e2e8f0;
}

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

html {
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: 'Inter', 'Segoe UI', system-ui, -apple-system, sans-serif;
    background: linear-gradient(135deg, #f8fafc 0%, #e0f2fe 50%, #f0f9ff 100%);
    color: var(--light-text);
    transition: background var(--transition), color var(--transition-fast);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

body.dark-mode {
    background: linear-gradient(135deg, #0f172a 0%, #1e3a5f 50%, #1e1b4b 100%);
    color: var(--dark-text);
    --glass-bg: rgba(30, 41, 59, 0.85);
    --glass-border: rgba(255, 255, 255, 0.08);
    --border-color: #334155;
}

.app-container {
    max-width: 1440px;
    margin: 0 auto;
    padding: 24px;
    flex: 1;
    display: flex;
    flex-direction: column;
}

header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 32px;
}

.logo-container {
    display: flex;
    align-items: center;
}

.logo-link {
    display: flex;
    align-items: center;
    text-decoration: none;
    gap: 12px;
}

.logo {
    height: 38px;
    transition: transform var(--transition);
}

.logo-link:hover .logo {
    transform: scale(1.05) translateZ(0);
}

h1 {
    margin: 0;
    font-size: 22px;
    font-weight: 700;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    letter-spacing: -0.02em;
}

main {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 24px;
}

.upload-section, .conversion-section, .features-section {
    background: var(--light-card);
    border-radius: var(--border-radius-lg);
    box-shadow: var(--box-shadow);
    border: 1px solid var(--border-color);
    padding: 24px;
    transition: all var(--transition);
}

.upload-section:hover, .conversion-section:hover {
    box-shadow: var(--box-shadow-lg);
}

.dark-mode .upload-section,
.dark-mode .conversion-section,
.dark-mode .features-section {
    background: var(--dark-card);
}

.upload-container {
    margin-bottom: 20px;
}

.upload-area {
    border: 2px dashed var(--border-color);
    border-radius: var(--border-radius-lg);
    padding: 48px 24px;
    text-align: center;
    transition: all var(--transition);
    cursor: pointer;
    position: relative;
    background: var(--light-card);
}

.upload-area:hover {
    border-color: var(--primary-color);
    background: var(--primary-light);
    transform: translateY(-2px) translateZ(0);
}

.dark-mode .upload-area {
    border-color: #475569;
    background: var(--dark-card);
}

.dark-mode .upload-area:hover {
    border-color: var(--primary-color);
    background: rgba(59, 130, 246, 0.1);
}

.upload-icon {
    font-size: 52px;
    color: var(--primary-color);
    margin-bottom: 16px;
    animation: bounceGentle 2s infinite;
}

@keyframes bounceGentle {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-6px); }
}

.formats {
    display: block;
    margin-top: 12px;
    font-size: 13px;
    color: #64748b;
}

.dark-mode .formats {
    color: #94a3b8;
}

.file-input {
    opacity: 0;
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    cursor: pointer;
}

.conversion-section {
    display: grid;
    grid-template-columns: 1fr;
    gap: 24px;
}

@media (min-width: 992px) {
    .conversion-section {
        grid-template-columns: 3fr 2fr;
    }
}

.audio-info-panel, .conversion-options {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

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

.waveform-container {
    margin-bottom: 12px;
    border-radius: var(--border-radius);
    overflow: hidden;
    background: linear-gradient(135deg, rgba(59, 130, 246, 0.05), rgba(139, 92, 246, 0.05));
    border: 1px solid var(--border-color);
}

.dark-mode .waveform-container {
    background: linear-gradient(135deg, rgba(59, 130, 246, 0.1), rgba(139, 92, 246, 0.1));
}

#waveform {
    margin-bottom: 8px;
}

.playback-controls {
    display: flex;
    align-items: center;
    flex-wrap: wrap;
    gap: 12px;
}

.control-btn {
    background: var(--light-card);
    border: 1px solid var(--border-color);
    font-size: 18px;
    cursor: pointer;
    width: 44px;
    height: 44px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition);
    color: var(--light-text);
    box-shadow: var(--box-shadow);
}

.dark-mode .control-btn {
    color: var(--dark-text);
    background: var(--dark-card);
    border-color: #475569;
}

.control-btn:hover:not(:disabled) {
    background: linear-gradient(135deg, var(--primary-color), var(--primary-hover));
    color: white;
    border-color: transparent;
    transform: scale(1.1) translateZ(0);
    box-shadow: 0 4px 14px var(--primary-glow);
}

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

.time-display {
    margin: 0 16px;
    font-family: 'JetBrains Mono', 'Consolas', monospace;
    font-size: 14px;
    font-weight: 600;
    color: var(--primary-color);
    background: var(--primary-light);
    padding: 6px 12px;
    border-radius: var(--border-radius-sm);
}

.volume-control {
    display: flex;
    align-items: center;
    margin-left: auto;
    gap: 10px;
}

.volume-control i {
    color: #64748b;
}

input[type="range"] {
    -webkit-appearance: none;
    appearance: none;
    width: 100px;
    height: 6px;
    background: var(--border-color);
    border-radius: 3px;
    outline: none;
    cursor: pointer;
}

.dark-mode input[type="range"] {
    background: #475569;
}

input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 16px;
    height: 16px;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    border-radius: 50%;
    cursor: pointer;
    box-shadow: 0 2px 8px var(--primary-glow);
    transition: transform var(--transition-fast);
}

input[type="range"]::-webkit-slider-thumb:hover {
    transform: scale(1.2);
}

.audio-details h3, .conversion-options h3 {
    font-size: 16px;
    margin-bottom: 16px;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    font-weight: 700;
}

.details-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
    gap: 14px;
}

.detail-item {
    background: linear-gradient(135deg, rgba(59, 130, 246, 0.05), rgba(139, 92, 246, 0.05));
    padding: 14px 16px;
    border-radius: var(--border-radius);
    transition: all var(--transition);
    border: 1px solid var(--border-color);
}

.detail-item:hover {
    transform: translateY(-2px) translateZ(0);
    box-shadow: var(--box-shadow);
}

.dark-mode .detail-item {
    background: linear-gradient(135deg, rgba(59, 130, 246, 0.1), rgba(139, 92, 246, 0.1));
}

.detail-label {
    font-size: 11px;
    color: #64748b;
    margin-bottom: 4px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    font-weight: 600;
}

.dark-mode .detail-label {
    color: #94a3b8;
}

.detail-value {
    font-weight: 700;
    font-size: 15px;
    color: var(--primary-color);
}

.option-group {
    margin-bottom: 18px;
}

.option-group label {
    display: block;
    margin-bottom: 8px;
    font-size: 13px;
    font-weight: 600;
    color: var(--light-text);
}

.dark-mode .option-group label {
    color: var(--dark-text);
}

.custom-select {
    position: relative;
    width: 100%;
}

.custom-select select {
    appearance: none;
    -webkit-appearance: none;
    width: 100%;
    padding: 12px 16px;
    font-size: 14px;
    border: 2px solid var(--border-color);
    border-radius: var(--border-radius);
    background: var(--light-card);
    color: var(--light-text);
    cursor: pointer;
    transition: all var(--transition-fast);
    font-weight: 500;
}

.dark-mode .custom-select select {
    background: var(--dark-card);
    border-color: #475569;
    color: var(--dark-text);
}

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

.select-arrow {
    position: absolute;
    right: 16px;
    top: 50%;
    transform: translateY(-50%);
    pointer-events: none;
    color: #64748b;
    transition: all var(--transition-fast);
}

.dark-mode .select-arrow {
    color: #94a3b8;
}

.custom-select select:focus + .select-arrow {
    color: var(--primary-color);
    transform: translateY(-50%) rotate(180deg);
}

.conversion-progress {
    margin: 20px 0;
}

.progress-label {
    display: flex;
    justify-content: space-between;
    margin-bottom: 8px;
    font-size: 13px;
    font-weight: 600;
}

.progress-bar {
    height: 10px;
    background: var(--border-color);
    border-radius: 5px;
    overflow: hidden;
    position: relative;
}

.dark-mode .progress-bar {
    background: #475569;
}

.progress-fill {
    height: 100%;
    width: 0;
    background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
    border-radius: 5px;
    transition: width var(--transition);
    position: relative;
}

.progress-fill::after {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,0.3), transparent);
    animation: shimmer 2s infinite;
    background-size: 200% 100%;
}

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

.action-buttons {
    display: flex;
    gap: 12px;
}

.action-btn {
    padding: 14px 24px;
    border: none;
    border-radius: var(--border-radius);
    background: var(--light-card);
    border: 1px solid var(--border-color);
    color: var(--light-text);
    cursor: pointer;
    transition: all var(--transition);
    font-size: 14px;
    font-weight: 600;
    display: flex;
    align-items: center;
    gap: 10px;
    flex: 1;
    justify-content: center;
}

.dark-mode .action-btn {
    background: var(--dark-card);
    border-color: #475569;
    color: var(--dark-text);
}

.action-btn:hover:not(:disabled) {
    transform: translateY(-3px) translateZ(0);
    box-shadow: var(--box-shadow-lg);
}

.dark-mode .action-btn:hover:not(:disabled) {
    background: #334155;
}

.action-btn.primary {
    background: linear-gradient(135deg, var(--primary-color), var(--primary-hover));
    color: white;
    border: none;
    box-shadow: 0 4px 14px var(--primary-glow);
}

.action-btn.primary:hover:not(:disabled) {
    box-shadow: 0 6px 20px var(--primary-glow);
}

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

.feature-heading {
    text-align: center;
    margin-bottom: 32px;
}

.feature-heading h2 {
    font-size: 26px;
    margin-bottom: 10px;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    display: inline-block;
    font-weight: 700;
}

.feature-heading p {
    color: #64748b;
    font-size: 15px;
}

.dark-mode .feature-heading p {
    color: #94a3b8;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 20px;
}

.feature-item {
    padding: 24px;
    background: linear-gradient(135deg, rgba(59, 130, 246, 0.04), rgba(139, 92, 246, 0.04));
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-lg);
    transition: all var(--transition);
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
}

.dark-mode .feature-item {
    background: linear-gradient(135deg, rgba(59, 130, 246, 0.08), rgba(139, 92, 246, 0.08));
}

.feature-item:hover {
    transform: translateY(-6px) translateZ(0);
    box-shadow: var(--box-shadow-lg);
    border-color: var(--primary-color);
}

.feature-icon {
    font-size: 40px;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 16px;
}

.feature-title {
    font-weight: 700;
    font-size: 17px;
    margin-bottom: 10px;
    color: var(--light-text);
}

.dark-mode .feature-title {
    color: var(--dark-text);
}

.feature-description {
    font-size: 14px;
    color: #64748b;
    line-height: 1.6;
}

.dark-mode .feature-description {
    color: #94a3b8;
}

.icon-button {
    background: transparent;
    border: none;
    cursor: pointer;
    font-size: 14px;
    color: #64748b;
    transition: all var(--transition-fast);
    display: flex;
    align-items: center;
    justify-content: center;
    width: 32px;
    height: 32px;
    border-radius: 50%;
}

.dark-mode .icon-button {
    color: #94a3b8;
}

.icon-button:hover {
    color: var(--primary-color);
    background: var(--primary-light);
    transform: scale(1.1) translateZ(0);
}

/* Footer styles - Enhanced */
.footer {
    margin-top: 40px;
    padding: 24px 0;
    text-align: center;
    border-top: 1px solid var(--border-color);
    background: var(--glass-bg);
    backdrop-filter: var(--glass-blur);
    transition: all var(--transition);
}

.dark-mode .footer {
    border-top-color: #334155;
}

.footer-content {
    max-width: 1440px;
    margin: 0 auto;
    padding: 0 24px;
}

.footer p {
    margin: 10px 0;
    font-size: 14px;
    color: #64748b;
}

.dark-mode .footer p {
    color: #94a3b8;
}

.footer-links {
    line-height: 1.8;
}

.footer a {
    color: var(--primary-color);
    text-decoration: none;
    transition: all var(--transition-fast);
    font-weight: 500;
}

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

.dmca-badge {
    display: inline-block;
    margin-bottom: 12px;
}

/* Toast Notifications - Enhanced */
#toast-container {
    position: fixed;
    bottom: 24px;
    right: 24px;
    z-index: 1000;
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.toast {
    padding: 14px 20px;
    border-radius: var(--border-radius);
    color: white;
    display: flex;
    align-items: center;
    box-shadow: var(--box-shadow-lg);
    max-width: 380px;
    animation: toastSlideIn 0.4s cubic-bezier(0.34, 1.56, 0.64, 1), toastFadeOut 0.5s 2.5s forwards;
    pointer-events: none;
    backdrop-filter: blur(8px);
}

@keyframes toastSlideIn {
    from {
        transform: translateX(100%) translateZ(0);
        opacity: 0;
    }
    to {
        transform: translateX(0) translateZ(0);
        opacity: 1;
    }
}

@keyframes toastFadeOut {
    from { opacity: 1; }
    to { opacity: 0; }
}

.toast.success { background: linear-gradient(135deg, var(--success-color), #059669); }
.toast.error { background: linear-gradient(135deg, var(--danger-color), #dc2626); }
.toast.warning { background: linear-gradient(135deg, var(--warning-color), #d97706); }
.toast.info { background: linear-gradient(135deg, var(--info-color), #0284c7); }

.toast i {
    margin-right: 12px;
    font-size: 18px;
}

/* Theme toggle button - Enhanced */
#theme-btn {
    background: var(--light-card);
    border: 1px solid var(--border-color);
    font-size: 16px;
    cursor: pointer;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition);
    color: var(--light-text);
    box-shadow: var(--box-shadow);
}

.dark-mode #theme-btn {
    color: var(--dark-text);
    background: var(--dark-card);
    border-color: #475569;
}

#theme-btn:hover {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    border-color: transparent;
    transform: rotate(20deg) scale(1.1) translateZ(0);
    box-shadow: 0 4px 14px var(--primary-glow);
}

/* Utility classes */
.hidden {
    display: none;
}

/* Responsive adjustments */
@media (max-width: 768px) {
    .action-buttons {
        flex-direction: column;
    }
    
    .playback-controls {
        justify-content: center;
    }
    
    .volume-control {
        margin: 12px 0 0 0;
        width: 100%;
        justify-content: center;
    }
    
    .details-grid {
        grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
    }
    
    .app-container {
        padding: 16px;
    }
}

/* Loading animation - Enhanced */
.loading {
    display: inline-block;
    width: 22px;
    height: 22px;
    border: 3px solid rgba(255,255,255,.3);
    border-radius: 50%;
    border-top-color: white;
    animation: spin 0.8s linear infinite;
}

@keyframes spin {
    to { transform: rotate(360deg) translateZ(0); }
}

/* Waveform styling */
#waveform > wave {
    border-radius: var(--border-radius);
}

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