/* ============================================
   AUDIOHM DESIGN SYSTEM V2 - OPTIMIZED
   Version: 2.0
   Last Updated: 2026-01-19
   ============================================ */

/* ============================================
   1. CSS VARIABLES
   ============================================ */
:root {
    /* Colors - Primary */
    --primary: #00F0FF;
    --primary-dark: #00C0CC;
    --primary-light: #00FFFF;

    /* Colors - Secondary */
    --secondary: #BF00FF;
    --secondary-dark: #9000CC;
    --secondary-light: #DF33FF;

    /* Colors - Accent */
    --accent: #FF006E;
    --accent-dark: #CC0058;
    --accent-light: #FF338E;

    /* Colors - Functional */
    --success: #00FF88;
    --warning: #FFB800;
    --error: #FF006E;
    --info: #00F0FF;

    /* Backgrounds */
    --bg-dark: #0A0E27;
    --bg-darker: #050814;
    --bg-card: rgba(15, 23, 50, 0.6);
    --bg-card-hover: rgba(15, 23, 50, 0.8);
    --bg-glass: rgba(10, 14, 39, 0.7);

    /* Text */
    --text-primary: #FFFFFF;
    --text-secondary: #A0A0C0;
    --text-muted: #6B7280;

    /* Borders */
    --border: rgba(0, 240, 255, 0.2);
    --border-hover: rgba(0, 240, 255, 0.4);

    /* Effects */
    --glow-primary: 0 0 20px rgba(0, 240, 255, 0.5);
    --glow-secondary: 0 0 20px rgba(191, 0, 255, 0.5);
    --glow-accent: 0 0 20px rgba(255, 0, 110, 0.5);

    /* Spacing */
    --space-xs: 0.5rem;
    --space-sm: 0.75rem;
    --space-md: 1rem;
    --space-lg: 1.5rem;
    --space-xl: 2rem;
    --space-2xl: 3rem;
    --space-3xl: 4rem;

    /* Border Radius */
    --radius-xs: 4px;
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 15px;
    --radius-xl: 20px;
    --radius-full: 50%;

    /* Typography */
    --font-heading: 'Righteous', sans-serif;
    --font-body: 'Poppins', sans-serif;

    /* Font Sizes */
    --text-xs: 0.75rem;
    --text-sm: 0.875rem;
    --text-base: 1rem;
    --text-lg: 1.125rem;
    --text-xl: 1.25rem;
    --text-2xl: 1.5rem;
    --text-3xl: 2rem;
    --text-4xl: 2.5rem;

    /* Z-Index Scale */
    --z-dropdown: 1000;
    --z-sticky: 1020;
    --z-fixed: 1030;
    --z-modal-backdrop: 1040;
    --z-modal: 1050;
    --z-toast: 1060;

    /* Transitions */
    --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-base: 300ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 400ms ease-out;
}

/* ============================================
   2. RESET & BASE STYLES
   ============================================ */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-body);
    font-size: var(--text-base);
    line-height: 1.6;
    color: var(--text-primary);
    background: var(--bg-dark);
    overflow-x: hidden;
    position: relative;
    min-height: 100vh;
}

/* Animated Background */
body::before {
    content: '';
    position: fixed;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background:
        radial-gradient(circle at 20% 80%, rgba(0, 240, 255, 0.1) 0%, transparent 50%),
        radial-gradient(circle at 80% 20%, rgba(191, 0, 255, 0.1) 0%, transparent 50%),
        radial-gradient(circle at 40% 40%, rgba(255, 0, 110, 0.05) 0%, transparent 50%);
    animation: gradientShift 20s ease infinite;
    z-index: -1;
    pointer-events: none;
}

/* Selection */
::selection {
    background: var(--primary);
    color: var(--bg-dark);
}

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

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

::-webkit-scrollbar-track {
    background: transparent;
}

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

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

/* ============================================
   3. LAYOUT & APP STRUCTURE
   ============================================ */
#app {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Screens */
.screen {
    width: 100%;
    min-height: 100vh;
}

.hidden {
    display: none !important;
}

.visible {
    display: block !important;
}

/* ============================================
   4. LOADING SCREEN
   ============================================ */
.loading-screen {
    position: fixed;
    inset: 0;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    background: var(--bg-dark);
    z-index: var(--z-modal);
}

.spinner {
    width: 80px;
    height: 80px;
    position: relative;
}

.spinner::before,
.spinner::after {
    content: '';
    position: absolute;
    inset: 0;
    border-radius: 50%;
    border: 4px solid transparent;
}

.spinner::before {
    border-top-color: var(--primary);
    animation: spin 1s linear infinite;
}

.spinner::after {
    border-bottom-color: var(--secondary);
    animation: spin 1.5s linear infinite reverse;
}

/* ============================================
   5. LOGIN SCREEN
   ============================================ */
.login-container {
    max-width: 400px;
    margin: 2rem auto;
    padding: var(--space-2xl);
    background: var(--bg-card);
    backdrop-filter: blur(10px);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
}

.logo {
    font-family: var(--font-heading);
    font-size: var(--text-3xl);
    text-align: center;
    margin-bottom: var(--space-xl);
    color: var(--primary);
    text-shadow: var(--glow-primary);
}

.login-form {
    display: flex;
    flex-direction: column;
    gap: var(--space-md);
}

.register-link {
    text-align: center;
    color: var(--text-secondary);
    margin-top: var(--space-md);
}

.register-link a {
    color: var(--primary);
    text-decoration: none;
}

.register-link a:hover {
    text-decoration: underline;
}

.error-message {
    padding: var(--space-md);
    background: rgba(255, 0, 110, 0.1);
    border: 1px solid var(--error);
    border-radius: var(--radius-md);
    color: var(--error);
    text-align: center;
    margin-top: var(--space-md);
}

/* ============================================
   6. MAIN APP LAYOUT
   ============================================ */
#main-app {
    display: flex;
    flex-direction: column;
    padding-bottom: 100px;
}

/* Mobile Menu Button */
.mobile-menu-btn {
    position: fixed;
    top: var(--space-md);
    left: var(--space-md);
    z-index: var(--z-sticky);
    background: var(--bg-glass);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: var(--space-sm) var(--space-md);
    color: var(--text-primary);
    cursor: pointer;
    display: none;
}

.mobile-menu-btn:hover {
    border-color: var(--primary);
    box-shadow: var(--glow-primary);
}

/* Sidebar */
.sidebar {
    position: fixed;
    left: 0;
    top: 0;
    width: 250px;
    height: 100vh;
    background: var(--bg-glass);
    backdrop-filter: blur(20px);
    border-right: 1px solid var(--border);
    display: flex;
    flex-direction: column;
    z-index: var(--z-sticky);
    transition: transform var(--transition-base);
}

.sidebar-header {
    padding: var(--space-xl) var(--space-lg);
    border-bottom: 1px solid var(--border);
}

.sidebar-nav {
    flex: 1;
    padding: var(--space-lg);
    display: flex;
    flex-direction: column;
    gap: var(--space-sm);
}

.nav-item {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    padding: var(--space-md);
    border-radius: var(--radius-md);
    color: var(--text-secondary);
    text-decoration: none;
    transition: all var(--transition-base);
}

.nav-item:hover {
    background: rgba(0, 240, 255, 0.1);
    color: var(--text-primary);
}

.nav-item.active {
    background: rgba(0, 240, 255, 0.2);
    color: var(--primary);
}

.nav-item i {
    width: 20px;
    text-align: center;
}

.sidebar-footer {
    padding: var(--space-lg);
    border-top: 1px solid var(--border);
}

/* Main Content */
.main-content {
    margin-left: 250px;
    flex: 1;
    padding: var(--space-xl);
}

/* Pages */
.page {
    display: none;
}

.page.active {
    display: block;
    animation: fadeIn 0.3s ease;
}

.page-header {
    margin-bottom: var(--space-2xl);
}

.page-header h1 {
    font-family: var(--font-heading);
    font-size: var(--text-3xl);
    margin-bottom: var(--space-sm);
    color: var(--text-primary);
}

.page-header p {
    color: var(--text-secondary);
}

/* Sections */
.section {
    margin-bottom: var(--space-3xl);
}

.section h2 {
    font-size: var(--text-2xl);
    margin-bottom: var(--space-lg);
    display: flex;
    align-items: center;
    gap: var(--space-sm);
}

.section h2 i {
    color: var(--primary);
}

/* Search Bar */
.search-bar {
    display: flex;
    gap: var(--space-md);
    margin-bottom: var(--space-xl);
}

.search-bar input {
    flex: 1;
    padding: var(--space-md) var(--space-lg);
    background: var(--bg-card);
    border: 2px solid var(--border);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    font-family: var(--font-body);
    font-size: var(--text-base);
    transition: all var(--transition-base);
}

.search-bar input:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: var(--glow-primary);
}

/* Track List */
.track-list {
    display: flex;
    flex-direction: column;
    gap: var(--space-md);
}

.track-item {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    padding: var(--space-md);
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    transition: all var(--transition-base);
    cursor: pointer;
}

.track-item:hover {
    border-color: var(--primary);
    background: var(--bg-card-hover);
    transform: translateY(-2px);
    box-shadow: var(--glow-primary);
}

.track-cover {
    width: 60px;
    height: 60px;
    border-radius: var(--radius-sm);
    object-fit: cover;
}

.track-info {
    flex: 1;
}

.track-title {
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: var(--space-xs);
}

.track-artist {
    font-size: var(--text-sm);
    color: var(--text-secondary);
}

.track-duration {
    font-size: var(--text-sm);
    color: var(--text-muted);
}

/* Playlist List */
.playlist-list {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: var(--space-lg);
}

.playlist-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: var(--space-md);
    transition: all var(--transition-base);
    cursor: pointer;
}

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

.playlist-cover {
    width: 100%;
    aspect-ratio: 1;
    border-radius: var(--radius-sm);
    object-fit: cover;
    margin-bottom: var(--space-md);
}

.playlist-name {
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: var(--space-xs);
}

.playlist-info {
    font-size: var(--text-sm);
    color: var(--text-secondary);
}

/* Loading */
.loading {
    text-align: center;
    padding: var(--space-2xl);
    color: var(--text-secondary);
}

/* ============================================
   7. PLAYER
   ============================================ */
.player {
    position: fixed;
    bottom: 0;
    left: 250px;
    right: 0;
    background: var(--bg-glass);
    backdrop-filter: blur(20px);
    border-top: 1px solid var(--border);
    padding: var(--space-md) var(--space-xl);
    display: flex;
    align-items: center;
    gap: var(--space-xl);
    z-index: var(--z-fixed);
}

/* Player Info */
.player-info {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    min-width: 250px;
}

.player-cover {
    width: 60px;
    height: 60px;
    border-radius: var(--radius-sm);
    object-fit: cover;
}

.player-details {
    flex: 1;
}

.player-title {
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: var(--space-xs);
}

.player-artist {
    font-size: var(--text-sm);
    color: var(--text-secondary);
}

/* Player Controls */
.player-controls {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    flex: 1;
    justify-content: center;
}

.btn-control {
    background: transparent;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    padding: var(--space-sm);
    border-radius: var(--radius-full);
    transition: all var(--transition-base);
    display: flex;
    align-items: center;
    justify-content: center;
}

.btn-control:hover {
    color: var(--text-primary);
    background: rgba(255, 255, 255, 0.1);
}

.btn-control.active {
    color: var(--primary);
}

.btn-play {
    width: 50px;
    height: 50px;
    background: var(--primary);
    color: var(--bg-dark);
    font-size: var(--text-lg);
}

.btn-play:hover {
    background: var(--primary-light);
    transform: scale(1.1);
    box-shadow: var(--glow-primary);
}

/* Player Progress */
.player-progress {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    flex: 1;
    max-width: 400px;
}

.time {
    font-size: var(--text-xs);
    color: var(--text-muted);
    min-width: 40px;
}

.progress-bar, .volume-bar {
    flex: 1;
    height: 4px;
    background: var(--border);
    border-radius: var(--radius-full);
    outline: none;
    cursor: pointer;
    appearance: none;
    -webkit-appearance: none;
}

.progress-bar::-webkit-slider-thumb,
.volume-bar::-webkit-slider-thumb {
    appearance: none;
    -webkit-appearance: none;
    width: 12px;
    height: 12px;
    background: var(--primary);
    border-radius: 50%;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.progress-bar::-webkit-slider-thumb:hover,
.volume-bar::-webkit-slider-thumb:hover {
    transform: scale(1.2);
    box-shadow: var(--glow-primary);
}

/* Player Volume */
.player-volume {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
}

.volume-bar {
    width: 100px;
}

/* Player Actions */
.player-actions {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
}

/* ============================================
   8. BUTTONS
   ============================================ */
.btn {
    position: relative;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-sm);
    padding: var(--space-md) var(--space-xl);
    border: none;
    border-radius: var(--radius-md);
    font-family: var(--font-body);
    font-size: var(--text-base);
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-base);
    overflow: hidden;
    text-decoration: none;
}

.btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.3), transparent);
    transition: left 0.5s ease;
}

.btn:hover::before {
    left: 100%;
}

.btn:hover {
    transform: translateY(-3px);
}

.btn:active {
    transform: translateY(-1px);
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: white;
}

.btn-primary:hover {
    box-shadow: var(--glow-primary), 0 10px 30px rgba(0, 240, 255, 0.3);
}

.btn-secondary {
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--border);
    color: var(--text-primary);
}

.btn-secondary:hover {
    background: rgba(255, 0, 110, 0.1);
    border-color: var(--accent);
    color: var(--accent);
}

/* ============================================
   9. FORMS
   ============================================ */
.form-group {
    margin-bottom: var(--space-lg);
}

.form-label {
    display: block;
    margin-bottom: var(--space-sm);
    font-weight: 500;
    color: var(--text-secondary);
}

.form-input {
    width: 100%;
    padding: var(--space-md) var(--space-md) var(--space-md) var(--space-2xl);
    background: rgba(255, 255, 255, 0.05);
    border: 2px solid var(--border);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    font-family: var(--font-body);
    font-size: var(--text-base);
    transition: all var(--transition-base);
}

.form-input:focus {
    outline: none;
    border-color: var(--primary);
    background: rgba(0, 240, 255, 0.05);
    box-shadow: var(--glow-primary);
}

.form-input::placeholder {
    color: var(--text-muted);
}

/* ============================================
   10. TOAST NOTIFICATIONS
   ============================================ */
.toast-container {
    position: fixed;
    top: var(--space-xl);
    right: var(--space-xl);
    z-index: var(--z-toast);
    display: flex;
    flex-direction: column;
    gap: var(--space-md);
}

.toast {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    padding: var(--space-md) var(--space-lg);
    background: var(--bg-glass);
    backdrop-filter: blur(20px);
    border: 1px solid var(--border);
    border-left: 4px solid var(--primary);
    border-radius: var(--radius-md);
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.4);
    animation: toastSlideIn 0.4s ease;
    min-width: 300px;
}

.toast.success {
    border-left-color: var(--success);
}

.toast.error {
    border-left-color: var(--error);
}

.toast.info {
    border-left-color: var(--info);
}

/* ============================================
   11. CARDS
   ============================================ */
.card {
    background: var(--bg-card);
    backdrop-filter: blur(10px);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: var(--space-lg);
    transition: all var(--transition-base);
}

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

/* ============================================
   12. ANIMATIONS
   ============================================ */
@keyframes gradientShift {
    0%, 100% {
        transform: translate(0, 0) rotate(0deg);
    }
    33% {
        transform: translate(30px, -30px) rotate(120deg);
    }
    66% {
        transform: translate(-20px, 20px) rotate(240deg);
    }
}

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

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

@keyframes toastSlideIn {
    from {
        transform: translateX(400px);
        opacity: 0;
    }
    to {
        transform: translateX(0);
        opacity: 1;
    }
}

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

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

/* ============================================
   13. RESPONSIVE DESIGN
   ============================================ */

/* Tablet (768px and below) */
@media (max-width: 768px) {
    .mobile-menu-btn {
        display: flex;
    }

    .sidebar {
        transform: translateX(-100%);
    }

    .sidebar.open {
        transform: translateX(0);
    }

    .main-content {
        margin-left: 0;
        padding: var(--space-md);
    }

    .player {
        left: 0;
        flex-wrap: wrap;
        padding: var(--space-md);
        gap: var(--space-sm);
    }

    .player-info {
        min-width: auto;
        flex: 1;
    }

    .player-cover {
        width: 40px;
        height: 40px;
    }

    .player-controls {
        order: 3;
        width: 100%;
        justify-content: space-around;
    }

    .player-progress {
        order: 2;
        max-width: none;
    }

    .player-volume,
    .player-actions {
        display: none;
    }

    .search-bar {
        flex-direction: column;
    }

    .playlist-list {
        grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
    }
}

/* Mobile (480px and below) */
@media (max-width: 480px) {
    .login-container {
        margin: 1rem;
        padding: var(--space-lg);
    }

    .logo {
        font-size: var(--text-2xl);
    }

    .playlist-list {
        grid-template-columns: 1fr;
    }

    .player-title {
        font-size: var(--text-sm);
    }

    .player-artist {
        font-size: var(--text-xs);
    }
}