/* CSS Variables for theming */
:root {
    --primary-color: #6366f1;
    --primary-hover: #4f46e5;
    --secondary-color: #64748b;
    --background-dark: #0f172a;
    --background-card: #1e293b;
    --background-hover: #334155;
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --text-muted: #64748b;
    --border-color: #334155;
    --success-color: #22c55e;
    --danger-color: #ef4444;
    --warning-color: #f59e0b;
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.3);
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 16px;
    --transition-fast: 150ms ease;
    --transition-normal: 250ms ease;
}

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

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background: linear-gradient(135deg, var(--background-dark) 0%, #1a1a2e 100%);
    color: var(--text-primary);
    min-height: 100vh;
    line-height: 1.6;
}

/* App Container */
.app-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 1rem;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Header */
header {
    text-align: center;
    padding: 2rem 1rem;
    margin-bottom: 1rem;
}

header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--primary-color), #a78bfa);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 0.5rem;
}

.tagline {
    color: var(--text-secondary);
    font-size: 1.1rem;
}

/* Main Content */
main {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

/* Section Styles */
section {
    background: var(--background-card);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
    border: 1px solid var(--border-color);
}

section h2 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.section-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 1rem;
    margin-bottom: 1rem;
}

.section-header h2 {
    margin-bottom: 0;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.625rem 1.25rem;
    border: none;
    border-radius: var(--radius-sm);
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-fast);
    text-decoration: none;
}

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

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

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

.btn-secondary:hover {
    background: #475569;
}

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

.btn-danger:hover {
    background: #dc2626;
}

.btn-icon-only {
    background: var(--background-hover);
    color: var(--text-primary);
    padding: 0.5rem;
    min-width: 40px;
    border: 1px solid var(--border-color);
}

.btn-icon-only:hover {
    background: var(--primary-color);
    border-color: var(--primary-color);
}

.btn-icon {
    font-size: 1.2rem;
    line-height: 1;
}

/* Category Tabs */
.category-tabs {
    display: flex;
    gap: 0.5rem;
    flex-wrap: wrap;
    margin-bottom: 1.5rem;
    padding-bottom: 1rem;
    border-bottom: 1px solid var(--border-color);
}

.category-tab {
    padding: 0.5rem 1rem;
    background: var(--background-hover);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    color: var(--text-secondary);
    cursor: pointer;
    transition: all var(--transition-fast);
    font-size: 0.9rem;
}

.category-tab:hover {
    background: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

.category-tab.active {
    background: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

/* Sound Grid */
.sound-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
    gap: 1rem;
}

.sound-card {
    background: var(--background-hover);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 1.25rem 1rem;
    text-align: center;
    cursor: pointer;
    transition: all var(--transition-normal);
    position: relative;
}

.sound-card:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary-color);
}

.sound-card.active {
    background: rgba(99, 102, 241, 0.2);
    border-color: var(--primary-color);
    box-shadow: 0 0 20px rgba(99, 102, 241, 0.3);
}

.sound-card .sound-icon {
    font-size: 2.5rem;
    margin-bottom: 0.75rem;
    display: block;
}

.sound-card .sound-name {
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-primary);
}

.sound-card .active-indicator {
    position: absolute;
    top: 8px;
    right: 8px;
    width: 10px;
    height: 10px;
    background: var(--success-color);
    border-radius: 50%;
    animation: pulse 1.5s infinite;
}

@keyframes pulse {
    0%, 100% { opacity: 1; transform: scale(1); }
    50% { opacity: 0.5; transform: scale(1.2); }
}

/* Active Sounds List */
.active-sounds-list {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.active-sound-item {
    display: flex;
    align-items: center;
    gap: 1rem;
    background: var(--background-hover);
    padding: 1rem;
    border-radius: var(--radius-md);
    border: 1px solid var(--border-color);
}

.active-sound-item .sound-info {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    min-width: 150px;
}

.active-sound-item .sound-icon {
    font-size: 1.5rem;
}

.active-sound-item .sound-name {
    font-weight: 500;
}

.active-sound-item .sound-controls {
    flex: 1;
    display: flex;
    align-items: center;
    gap: 1rem;
    flex-wrap: wrap;
}

.volume-control {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    flex: 1;
    min-width: 150px;
}

.volume-control input[type="range"] {
    flex: 1;
    min-width: 100px;
}

.volume-value {
    font-size: 0.85rem;
    color: var(--text-secondary);
    min-width: 40px;
}

.loop-toggle {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.loop-toggle label {
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.active-sound-item .remove-btn {
    background: transparent;
    border: none;
    color: var(--text-muted);
    cursor: pointer;
    padding: 0.5rem;
    font-size: 1.2rem;
    transition: color var(--transition-fast);
}

.active-sound-item .remove-btn:hover {
    color: var(--danger-color);
}

/* Master Controls */
.master-controls {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    flex-wrap: wrap;
}

.master-volume {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    background: var(--background-hover);
    padding: 0.5rem 1rem;
    border-radius: var(--radius-sm);
    border: 1px solid var(--border-color);
}

.master-volume span:first-child {
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.master-volume input[type="range"] {
    width: 100px;
}

/* Range Input Styling */
input[type="range"] {
    -webkit-appearance: none;
    appearance: none;
    height: 6px;
    background: var(--border-color);
    border-radius: 3px;
    cursor: pointer;
}

input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 16px;
    height: 16px;
    background: var(--primary-color);
    border-radius: 50%;
    cursor: pointer;
    transition: transform var(--transition-fast);
}

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

input[type="range"]::-moz-range-thumb {
    width: 16px;
    height: 16px;
    background: var(--primary-color);
    border-radius: 50%;
    cursor: pointer;
    border: none;
}

/* Checkbox Styling */
input[type="checkbox"] {
    width: 18px;
    height: 18px;
    accent-color: var(--primary-color);
    cursor: pointer;
}

/* Saved Mixes */
.saved-mixes-list {
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
}

.saved-mix-card {
    background: var(--background-hover);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 1rem;
    min-width: 200px;
    max-width: 300px;
    flex: 1;
}

.saved-mix-card .mix-name {
    font-weight: 600;
    margin-bottom: 0.5rem;
    font-size: 1rem;
}

.saved-mix-card .mix-sounds {
    font-size: 0.85rem;
    color: var(--text-secondary);
    margin-bottom: 1rem;
}

.saved-mix-card .mix-actions {
    display: flex;
    gap: 0.5rem;
}

.saved-mix-card .mix-actions button {
    flex: 1;
    padding: 0.5rem;
    font-size: 0.85rem;
}

/* Empty State */
.empty-state {
    color: var(--text-muted);
    text-align: center;
    padding: 2rem;
    font-style: italic;
}

/* Modal */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.7);
    z-index: 1000;
    align-items: center;
    justify-content: center;
    padding: 1rem;
}

.modal.active {
    display: flex;
}

.modal-content {
    background: var(--background-card);
    border-radius: var(--radius-lg);
    width: 100%;
    max-width: 400px;
    border: 1px solid var(--border-color);
    animation: modalSlideIn 0.3s ease;
}

@keyframes modalSlideIn {
    from {
        opacity: 0;
        transform: translateY(-20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 1.5rem;
    border-bottom: 1px solid var(--border-color);
}

.modal-header h3 {
    font-size: 1.1rem;
    font-weight: 600;
}

.modal-close {
    background: transparent;
    border: none;
    color: var(--text-muted);
    font-size: 1.5rem;
    cursor: pointer;
    padding: 0;
    line-height: 1;
}

.modal-close:hover {
    color: var(--text-primary);
}

.modal-body {
    padding: 1.5rem;
}

.modal-body label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
    color: var(--text-secondary);
}

.modal-body input[type="text"] {
    width: 100%;
    padding: 0.75rem 1rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    background: var(--background-hover);
    color: var(--text-primary);
    font-size: 1rem;
}

.modal-body input[type="text"]:focus {
    outline: none;
    border-color: var(--primary-color);
}

.modal-footer {
    display: flex;
    gap: 0.75rem;
    justify-content: flex-end;
    padding: 1rem 1.5rem;
    border-top: 1px solid var(--border-color);
}

/* Footer */
footer {
    text-align: center;
    padding: 2rem 1rem;
    margin-top: 2rem;
    border-top: 1px solid var(--border-color);
}

footer p {
    color: var(--text-muted);
    font-size: 0.9rem;
}

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

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

/* Responsive Design */
@media (max-width: 768px) {
    header h1 {
        font-size: 1.75rem;
    }

    .tagline {
        font-size: 1rem;
    }

    section {
        padding: 1rem;
    }

    .section-header {
        flex-direction: column;
        align-items: flex-start;
    }

    .master-controls {
        width: 100%;
        justify-content: flex-start;
    }

    .master-volume {
        flex: 1;
        justify-content: space-between;
    }

    .master-volume input[type="range"] {
        flex: 1;
    }

    .sound-grid {
        grid-template-columns: repeat(auto-fill, minmax(100px, 1fr));
        gap: 0.75rem;
    }

    .sound-card {
        padding: 1rem 0.75rem;
    }

    .sound-card .sound-icon {
        font-size: 2rem;
    }

    .sound-card .sound-name {
        font-size: 0.8rem;
    }

    .active-sound-item {
        flex-direction: column;
        align-items: flex-start;
    }

    .active-sound-item .sound-info {
        width: 100%;
        justify-content: space-between;
    }

    .active-sound-item .sound-controls {
        width: 100%;
    }

    .volume-control {
        width: 100%;
    }

    .saved-mix-card {
        min-width: 100%;
        max-width: 100%;
    }

    .category-tabs {
        gap: 0.375rem;
    }

    .category-tab {
        padding: 0.375rem 0.75rem;
        font-size: 0.8rem;
    }
}

@media (max-width: 480px) {
    .app-container {
        padding: 0.5rem;
    }

    header {
        padding: 1.5rem 0.5rem;
    }

    header h1 {
        font-size: 1.5rem;
    }

    .sound-grid {
        grid-template-columns: repeat(3, 1fr);
    }

    .saved-mix-card .mix-actions {
        flex-direction: column;
    }

    .modal-content {
        margin: 0 0.5rem;
    }
}

/* 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 */
button:focus-visible,
input:focus-visible,
.category-tab:focus-visible,
.sound-card:focus-visible {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}