/* Base Styles - Apple Music */

/* App Container */
#app {
    position: fixed;
    inset: 0;
    display: flex;
    flex-direction: column;
    background: var(--bg-primary);
    overflow: hidden;
}

/* Header */
.app-header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: calc(var(--header-height) + var(--safe-area-top));
    padding-top: var(--safe-area-top);
    padding-left: var(--space-lg);
    padding-right: var(--space-lg);
    display: flex;
    align-items: center;
    justify-content: space-between;
    background: rgba(0, 0, 0, 0.72);
    backdrop-filter: blur(var(--blur-lg));
    -webkit-backdrop-filter: blur(var(--blur-lg));
    z-index: var(--z-sticky);
    border-bottom: 0.5px solid var(--separator);
}

.header-title {
    font-size: var(--text-2xl);
    font-weight: var(--font-bold);
    letter-spacing: var(--tracking-tight);
}

.header-btn {
    width: 36px;
    height: 36px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: var(--radius-full);
    transition: background var(--transition-fast);
}

.header-btn:active {
    background: var(--fill-tertiary);
}

.profile-avatar {
    width: 28px;
    height: 28px;
    border-radius: var(--radius-full);
    background: linear-gradient(135deg, #5E5CE6 0%, #BF5AF2 100%);
}

/* Main Content */
.main-content {
    position: fixed;
    top: calc(var(--header-height) + var(--safe-area-top));
    left: 0;
    right: 0;
    bottom: calc(var(--tab-bar-height) + var(--safe-area-bottom));
    overflow: hidden;
}

/* Views */
.view {
    position: absolute;
    inset: 0;
    display: none;
    flex-direction: column;
    opacity: 0;
    transform: translateX(20px);
    transition: opacity var(--transition-normal), transform var(--transition-normal);
}

.view.active {
    display: flex;
    opacity: 1;
    transform: translateX(0);
}

.section-scroll {
    flex: 1;
    overflow-y: auto;
    overflow-x: hidden;
    -webkit-overflow-scrolling: touch;
    padding-bottom: var(--mini-player-height);
}

/* Content Sections */
.content-section {
    padding: var(--space-xl) 0;
}

.content-section:first-child {
    padding-top: var(--space-lg);
}

.section-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 var(--space-lg);
    margin-bottom: var(--space-md);
}

.section-title {
    font-size: var(--text-xl);
    font-weight: var(--font-bold);
    letter-spacing: var(--tracking-tight);
    padding: 0 var(--space-lg);
    margin-bottom: var(--space-md);
}

.section-header .section-title {
    padding: 0;
    margin: 0;
}

.add-btn {
    width: 28px;
    height: 28px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--apple-red);
}

.add-btn svg {
    width: 24px;
    height: 24px;
    fill: currentColor;
}

/* Horizontal Scroll */
.horizontal-scroll {
    display: flex;
    gap: var(--space-md);
    padding: 0 var(--space-lg);
    overflow-x: auto;
    scroll-snap-type: x mandatory;
    -webkit-overflow-scrolling: touch;
}

.horizontal-scroll::-webkit-scrollbar {
    display: none;
}

/* Empty State */
.empty-state {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: var(--space-lg);
    padding: var(--space-3xl);
    color: var(--text-secondary);
    text-align: center;
}

.empty-state.small {
    padding: var(--space-xl);
    min-width: 200px;
}

.empty-state p {
    font-size: var(--text-base);
}

/* Buttons */
.btn-primary {
    padding: var(--space-md) var(--space-xl);
    background: var(--apple-red);
    color: white;
    border-radius: var(--radius-full);
    font-size: var(--text-base);
    font-weight: var(--font-semibold);
    transition: transform var(--transition-fast), opacity var(--transition-fast);
}

.btn-primary:active {
    transform: scale(0.97);
    opacity: 0.9;
}

.btn-secondary {
    padding: var(--space-md) var(--space-xl);
    background: var(--fill-tertiary);
    color: var(--text-primary);
    border-radius: var(--radius-full);
    font-size: var(--text-base);
    font-weight: var(--font-semibold);
    transition: transform var(--transition-fast), background var(--transition-fast);
}

.btn-secondary:active {
    transform: scale(0.97);
    background: var(--fill-secondary);
}

/* Typography Classes */
.text-xs {
    font-size: var(--text-xs);
}

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

.text-base {
    font-size: var(--text-base);
}

.text-md {
    font-size: var(--text-md);
}

.text-lg {
    font-size: var(--text-lg);
}

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

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

.font-regular {
    font-weight: var(--font-regular);
}

.font-medium {
    font-weight: var(--font-medium);
}

.font-semibold {
    font-weight: var(--font-semibold);
}

.font-bold {
    font-weight: var(--font-bold);
}

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

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

.text-tertiary {
    color: var(--text-tertiary);
}

.text-accent {
    color: var(--apple-red);
}

/* Utility Classes */
.hidden {
    display: none !important;
}

.truncate {
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.line-clamp-2 {
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

/* Animations */
@keyframes fadeIn {
    from {
        opacity: 0;
    }

    to {
        opacity: 1;
    }
}

@keyframes slideUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

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

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes scaleIn {
    from {
        opacity: 0;
        transform: scale(0.95);
    }

    to {
        opacity: 1;
        transform: scale(1);
    }
}

@keyframes pulse {

    0%,
    100% {
        opacity: 1;
    }

    50% {
        opacity: 0.5;
    }
}

@keyframes spin {
    from {
        transform: rotate(0deg);
    }

    to {
        transform: rotate(360deg);
    }
}

/* Loading Animation */
.loader {
    width: 32px;
    height: 32px;
    border: 3px solid var(--fill-tertiary);
    border-top-color: var(--apple-red);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

.loading-overlay {
    position: fixed;
    inset: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(0, 0, 0, 0.5);
    z-index: var(--z-modal);
    backdrop-filter: blur(var(--blur-sm));
    -webkit-backdrop-filter: blur(var(--blur-sm));
}

/* Skeleton Loading */
.skeleton {
    background: linear-gradient(90deg,
            var(--bg-secondary) 25%,
            var(--bg-tertiary) 50%,
            var(--bg-secondary) 75%);
    background-size: 200% 100%;
    animation: shimmer 1.5s infinite;
    border-radius: var(--radius-md);
}

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

    100% {
        background-position: -200% 0;
    }
}