:root {
    /* Modern Color Palette */
    --primary-blue: hsl(210, 100%, 45%);
    --primary-blue-dark: hsl(210, 100%, 35%);
    --accent-cyan: hsl(190, 100%, 50%);
    --accent-purple: hsl(270, 80%, 60%);
    --bg-dark: hsl(220, 25%, 10%);
    --bg-darker: hsl(220, 25%, 5%);
    --bg-card: hsl(220, 20%, 15%);
    --text-primary: hsl(0, 0%, 95%);
    --text-secondary: hsl(0, 0%, 70%);
    --border-color: hsl(220, 20%, 25%);
    --success: hsl(140, 70%, 50%);
    --error: hsl(0, 80%, 60%);
    --warning: hsl(40, 90%, 55%);
    
    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    
    /* Typography */
    --font-main: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-heading: 'Outfit', var(--font-main);
    
    /* Border Radius */
    --radius-sm: 0.5rem;
    --radius-md: 1rem;
    --radius-lg: 1.5rem;
    
    /* Shadows */
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.5);
    --shadow-glow: 0 0 20px rgba(0, 170, 255, 0.3);
}

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

html {
    font-size: 16px;
}

body {
    font-family: var(--font-main);
    background: linear-gradient(135deg, var(--bg-darker) 0%, var(--bg-dark) 100%);
    color: var(--text-primary);
    min-height: 100vh;
    line-height: 1.6;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-heading);
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: var(--spacing-sm);
}

h1 { font-size: 2.5rem; }
h2 { font-size: 2rem; }
h3 { font-size: 1.5rem; }
h4 { font-size: 1.25rem; }

/* Container */
.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

/* Header */
.header {
    background: var(--bg-card);
    border-bottom: 2px solid var(--border-color);
    padding: var(--spacing-md) 0;
    position: sticky;
    top: 0;
    z-index: 1000;
    backdrop-filter: blur(10px);
}

.header-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--spacing-md);
}

.logo-container {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.logo {
    height: 50px;
    width: auto;
    object-fit: contain;
    transition: transform 0.3s ease;
}

.logo:hover {
    transform: scale(1.05);
}

.header-title {
    font-size: 1.75rem;
    background: linear-gradient(135deg, var(--primary-blue), var(--accent-cyan));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.user-info {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.user-badge {
    padding: var(--spacing-xs) var(--spacing-sm);
    background: linear-gradient(135deg, var(--primary-blue), var(--accent-purple));
    border-radius: var(--radius-md);
    font-size: 0.875rem;
    font-weight: 600;
}

/* Buttons */
.btn {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: var(--radius-md);
    font-family: var(--font-main);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    text-decoration: none;
    display: inline-block;
    text-align: center;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary-blue), var(--accent-cyan));
    color: white;
    box-shadow: var(--shadow-sm);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md), var(--shadow-glow);
}

.btn-secondary {
    background: var(--bg-card);
    color: var(--text-primary);
    border: 2px solid var(--border-color);
}

.btn-secondary:hover {
    border-color: var(--primary-blue);
    background: var(--bg-darker);
}

.btn-danger {
    background: linear-gradient(135deg, var(--error), hsl(0, 80%, 50%));
    color: white;
}

.btn-danger:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.btn-success {
    background: linear-gradient(135deg, var(--success), hsl(140, 70%, 40%));
    color: white;
}

.btn-success:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none !important;
}

/* Cards */
.card {
    background: var(--bg-card);
    border-radius: var(--radius-lg);
    padding: var(--spacing-md);
    box-shadow: var(--shadow-md);
    border: 1px solid var(--border-color);
    transition: all 0.3s ease;
}

.card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary-blue);
}

.card-glass {
    background: rgba(255, 255, 255, 0.05);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.1);
}

/* Forms */
.form-group {
    margin-bottom: var(--spacing-md);
}

.form-label {
    display: block;
    margin-bottom: var(--spacing-xs);
    font-weight: 600;
    color: var(--text-primary);
}

.form-input,
.form-select,
.form-textarea {
    width: 100%;
    padding: 0.75rem 1rem;
    background: var(--bg-darker);
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    font-family: var(--font-main);
    font-size: 1rem;
    transition: all 0.3s ease;
}

.form-input:focus,
.form-select:focus,
.form-textarea:focus {
    outline: none;
    border-color: var(--primary-blue);
    box-shadow: 0 0 0 3px rgba(0, 170, 255, 0.2);
}

.form-textarea {
    resize: vertical;
    min-height: 100px;
}

/* Grid Layouts */
.grid {
    display: grid;
    gap: var(--spacing-md);
}

.grid-2 {
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
}

.grid-3 {
    grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
}

.grid-4 {
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
}

/* Notebook Cards */
.notebook-card {
    cursor: pointer;
    overflow: hidden;
}

.notebook-image {
    width: 100%;
    height: 220px;
    object-fit: cover;
    border-radius: var(--radius-md);
    margin-bottom: var(--spacing-sm);
    background: var(--bg-darker);
}

.notebook-brand {
    font-size: 0.875rem;
    color: var(--accent-cyan);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.notebook-model {
    font-size: 1.25rem;
    font-weight: 700;
    margin: var(--spacing-xs) 0;
}

.notebook-specs {
    color: var(--text-secondary);
    font-size: 0.875rem;
    margin-bottom: var(--spacing-sm);
}

.notebook-price {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-top: var(--spacing-sm);
    border-top: 1px solid var(--border-color);
}

.price-label {
    font-size: 0.75rem;
    color: var(--text-secondary);
    text-transform: uppercase;
}

.price-value {
    font-size: 1.5rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--success), var(--accent-cyan));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* Search and Filters */
.search-filter-section {
    background: var(--bg-card);
    padding: var(--spacing-lg);
    border-radius: var(--radius-lg);
    margin-bottom: var(--spacing-lg);
    box-shadow: var(--shadow-md);
}

.search-bar {
    position: relative;
    margin-bottom: var(--spacing-md);
}

.search-bar input {
    padding-left: 3rem;
}

.search-icon {
    position: absolute;
    left: 1rem;
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-secondary);
    font-size: 1.25rem;
}

.filters {
    display: flex;
    gap: var(--spacing-sm);
    flex-wrap: wrap;
}

.filter-select {
    flex: 1;
    min-width: 200px;
}

/* Carousel */
.carousel {
    position: relative;
    width: 100%;
    max-width: 800px;
    margin: 0 auto var(--spacing-lg);
    border-radius: var(--radius-lg);
    overflow: hidden;
    background: var(--bg-darker);
}

.carousel-image {
    width: 100%;
    height: 500px;
    object-fit: contain;
    background: var(--bg-darker);
}

.carousel-controls {
    position: absolute;
    top: 50%;
    width: 100%;
    display: flex;
    justify-content: space-between;
    padding: 0 var(--spacing-sm);
    transform: translateY(-50%);
    pointer-events: none;
}

.carousel-btn {
    pointer-events: all;
    background: rgba(0, 0, 0, 0.6);
    color: white;
    border: none;
    width: 50px;
    height: 50px;
    border-radius: 50%;
    cursor: pointer;
    transition: all 0.3s ease;
    font-size: 1.5rem;
}

.carousel-btn:hover {
    background: var(--primary-blue);
    transform: scale(1.1);
}

.carousel-indicators {
    display: flex;
    justify-content: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-sm);
    background: rgba(0, 0, 0, 0.3);
}

.carousel-dot {
    width: 10px;
    height: 10px;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.4);
    border: none;
    cursor: pointer;
    transition: all 0.3s ease;
}

.carousel-dot.active {
    background: var(--primary-blue);
    transform: scale(1.3);
}

/* Modal */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.8);
    backdrop-filter: blur(5px);
    z-index: 2000;
    padding: var(--spacing-md);
    overflow-y: auto;
}

.modal.active {
    display: flex;
    align-items: center;
    justify-content: center;
}

.modal-content {
    background: var(--bg-card);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    max-width: 600px;
    width: 100%;
    max-height: 90vh;
    overflow-y: auto;
    box-shadow: var(--shadow-lg);
    animation: modalSlideIn 0.3s ease;
}

@keyframes modalSlideIn {
    from {
        opacity: 0;
        transform: translateY(-50px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-md);
    padding-bottom: var(--spacing-sm);
    border-bottom: 2px solid var(--border-color);
}

.modal-close {
    background: none;
    border: none;
    color: var(--text-secondary);
    font-size: 2rem;
    cursor: pointer;
    transition: color 0.3s ease;
}

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

/* Toast Notifications */
.toast {
    position: fixed;
    top: var(--spacing-md);
    right: var(--spacing-md);
    background: var(--bg-card);
    padding: var(--spacing-md);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-lg);
    z-index: 3000;
    min-width: 300px;
    animation: toastSlideIn 0.3s ease;
}

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

.toast.success {
    border-left: 4px solid var(--success);
}

.toast.error {
    border-left: 4px solid var(--error);
}

.toast.warning {
    border-left: 4px solid var(--warning);
}

/* Loading Spinner */
.loading {
    display: inline-block;
    width: 40px;
    height: 40px;
    border: 4px solid var(--border-color);
    border-top-color: var(--primary-blue);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

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

.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.7);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 9999;
}

/* Utility Classes */
.text-center { text-align: center; }
.text-right { text-align: right; }
.text-secondary { color: var(--text-secondary); }
.mt-1 { margin-top: var(--spacing-sm); }
.mt-2 { margin-top: var(--spacing-md); }
.mt-3 { margin-top: var(--spacing-lg); }
.mb-1 { margin-bottom: var(--spacing-sm); }
.mb-2 { margin-bottom: var(--spacing-md); }
.mb-3 { margin-bottom: var(--spacing-lg); }
.hidden { display: none; }

/* Responsive Design */
@media (max-width: 768px) {
    html {
        font-size: 14px;
    }
    
    .header-title {
        font-size: 1.25rem;
    }
    
    .logo {
        height: 40px;
    }
    
    .logo-container {
        flex-direction: column;
        gap: var(--spacing-xs);
    }
    
    .filters {
        flex-direction: column;
    }
    
    .filter-select {
        width: 100%;
    }
    
    .carousel-image {
        height: 300px;
    }
    
    .grid-2,
    .grid-3,
    .grid-4 {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    .header-content {
        flex-direction: column;
        text-align: center;
    }
    
    .user-info {
        width: 100%;
        justify-content: center;
    }
}