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

:root {
    --primary-color: #0066cc;
    --primary-hover: #0052a3;
    --secondary-color: #17a2b8;
    --accent-color: #28a745;
    --text-primary: #2c3e50;
    --text-secondary: #6c757d;
    --text-muted: #868e96;
    --background: #ffffff;
    --surface: #f8f9fa;
    --border: #dee2e6;
    --shadow: rgba(0, 0, 0, 0.1);
    --shadow-hover: rgba(0, 0, 0, 0.15);

    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;

    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --radius-xl: 16px;

    --transition-fast: 0.15s ease;
    --transition-normal: 0.3s ease;
    --transition-slow: 0.5s ease;

    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-size-xs: 0.75rem;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 1.875rem;
    --font-size-4xl: 2.25rem;
}

[data-theme="dark"] {
    --primary-color: #4dabf7;
    --primary-hover: #339af0;
    --secondary-color: #20c997;
    --accent-color: #51cf66;
    --text-primary: #f1f3f4;
    --text-secondary: #adb5bd;
    --text-muted: #6c757d;
    --background: #121212;
    --surface: #1e1e1e;
    --border: #343a40;
    --shadow: rgba(0, 0, 0, 0.3);
    --shadow-hover: rgba(0, 0, 0, 0.4);
}

body {
    font-family: var(--font-family);
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--background);
    transition: background-color var(--transition-normal), color var(--transition-normal);
    overflow-x: hidden;
    margin: 0;
    padding: 0;
}

/* Remove gaps between header and content */
.main-content {
    margin-top: 0;
    padding-top: 0;
}
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

@media (min-width: 768px) {
    .container {
        padding: 0 var(--spacing-lg);
    }
}

/* Navigation */
.navbar {
    background: var(--background);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border);
    position: sticky;
    top: 0;
    margin-bottom: 0;
    z-index: 1000;
    transition: all var(--transition-normal);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 64px;
}

.nav-brand h1 {
    font-size: var(--font-size-xl);
    font-weight: 700;
    color: var(--primary-color);
}

.nav-menu {
    display: none;
    align-items: center;
    gap: var(--spacing-lg);
}

@media (min-width: 768px) {
    .nav-menu {
        display: flex;
    }
}

.nav-link {
    text-decoration: none;
    color: var(--text-secondary);
    font-weight: 500;
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--radius-md);
    transition: all var(--transition-fast);
    position: relative;
}

.nav-link:hover,
.nav-link.active {
    color: var(--primary-color);
    background-color: var(--surface);
}

.theme-toggle {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: var(--spacing-sm);
    cursor: pointer;
    font-size: var(--font-size-lg);
    transition: all var(--transition-fast);
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.theme-toggle:hover {
    background-color: var(--primary-color);
    color: white;
    transform: scale(1.05);
}

.nav-hamburger {
    display: flex;
    flex-direction: column;
    cursor: pointer;
    gap: 4px;
}

@media (min-width: 768px) {
    .nav-hamburger {
        display: none;
    }
}

.nav-hamburger span {
    width: 25px;
    height: 3px;
    background-color: var(--text-primary);
    transition: all var(--transition-fast);
    border-radius: 2px;
}

/* Mobile menu active states */
.nav-hamburger.active span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
}

.nav-hamburger.active span:nth-child(2) {
    opacity: 0;
}

.nav-hamburger.active span:nth-child(3) {
    transform: rotate(-45deg) translate(7px, -6px);
}

/* Mobile menu styles */
@media (max-width: 767px) {
    .nav-menu {
        display: flex !important;
        position: fixed;
        top: 70px;
        left: 0;
        width: 100%;
        height: calc(100vh - 70px);
        background: var(--background);
        flex-direction: column;
        justify-content: flex-start;
        align-items: center;
        padding-top: var(--spacing-xl);
        transform: translateX(-100%);
        transition: transform var(--transition-normal);
        z-index: 1000;
        border-top: 1px solid var(--border);
        box-shadow: 0 4px 12px var(--shadow);
    }

    .nav-menu.active {
        transform: translateX(0);
    }

    .nav-menu .nav-link {
        padding: var(--spacing-lg);
        width: 100%;
        text-align: center;
        border-bottom: 1px solid var(--border);
        display: block;
    }
}

/* Prevent body scroll when mobile menu is open */
body.menu-open {
    overflow: hidden;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-sm) var(--spacing-lg);
    border: none;
    border-radius: var(--radius-md);
    font-size: var(--font-size-base);
    font-weight: 500;
    text-decoration: none;
    cursor: pointer;
    transition: all var(--transition-fast);
    min-height: 44px;
    gap: var(--spacing-sm);
}

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

.btn-primary:hover {
    background-color: var(--primary-hover);
    transform: translateY(-1px);
    box-shadow: 0 4px 12px var(--shadow-hover);
}

.btn-secondary {
    background-color: var(--surface);
    color: var(--text-primary);
    border: 1px solid var(--border);
}

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

.btn-sm {
    padding: var(--spacing-xs) var(--spacing-md);
    font-size: var(--font-size-sm);
    min-height: 36px;
}

/* Form Elements */
.form-group {
    margin-bottom: var(--spacing-lg);
}

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

.form-input,
.form-select,
.form-textarea {
    width: 100%;
    padding: var(--spacing-md);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    font-size: var(--font-size-base);
    background-color: var(--background);
    color: var(--text-primary);
    transition: all var(--transition-fast);
    min-height: 44px;
}

.form-input:focus,
.form-select:focus,
.form-textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(0, 102, 204, 0.1);
}

.form-textarea {
    resize: vertical;
    min-height: 120px;
}

/* Cards */
.card {
    background: var(--background);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    overflow: hidden;
    transition: all var(--transition-normal);
    box-shadow: 0 2px 8px var(--shadow);
}

.card:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 24px var(--shadow-hover);
    border-color: var(--primary-color);
}

.card-header {
    padding: var(--spacing-lg);
    border-bottom: 1px solid var(--border);
}

.card-body {
    padding: var(--spacing-lg);
}

.card-footer {
    padding: var(--spacing-lg);
    border-top: 1px solid var(--border);
    background-color: var(--surface);
}

/* Badges */
.badge {
    display: inline-flex;
    align-items: center;
    padding: var(--spacing-xs) var(--spacing-sm);
    font-size: var(--font-size-xs);
    font-weight: 500;
    border-radius: var(--radius-sm);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.badge-success {
    background-color: var(--accent-color);
    color: white;
}

.badge-warning {
    background-color: #ffc107;
    color: #000;
}

.badge-danger {
    background-color: #dc3545;
    color: white;
}

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

/* Loading States */
.loading {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-2xl);
    color: var(--text-muted);
}

.spinner {
    width: 40px;
    height: 40px;
    border: 4px solid var(--border);
    border-left: 4px solid var(--primary-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin-bottom: var(--spacing-md);
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* Footer */
.footer {
    background-color: var(--surface);
    border-top: 1px solid var(--border);
    margin-top: var(--spacing-2xl);
    padding: var(--spacing-2xl) 0 var(--spacing-md);
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-xl);
    margin-bottom: var(--spacing-xl);
}

.footer-section h3,
.footer-section h4 {
    margin-bottom: var(--spacing-md);
    color: var(--text-primary);
}

.footer-section p {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-sm);
}

.footer-section a {
    display: block;
    color: var(--text-secondary);
    text-decoration: none;
    margin-bottom: var(--spacing-sm);
    transition: color var(--transition-fast);
}

.footer-section a:hover {
    color: var(--primary-color);
}

.footer-bottom {
    text-align: center;
    padding-top: var(--spacing-md);
    border-top: 1px solid var(--border);
    color: var(--text-muted);
}

/* Responsive Design */
@media (max-width: 767px) {
    .container {
        padding: 0 var(--spacing-sm);
    }
    
    .btn {
        font-size: var(--font-size-sm);
        padding: var(--spacing-sm) var(--spacing-md);
    }
    
    .card-header,
    .card-body,
    .card-footer {
        padding: var(--spacing-md);
    }
}

/* Utility Classes */
.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

.mb-0 { margin-bottom: 0; }
.mb-1 { margin-bottom: var(--spacing-xs); }
.mb-2 { margin-bottom: var(--spacing-sm); }
.mb-3 { margin-bottom: var(--spacing-md); }
.mb-4 { margin-bottom: var(--spacing-lg); }
.mb-5 { margin-bottom: var(--spacing-xl); }

.mt-0 { margin-top: 0; }
.mt-1 { margin-top: var(--spacing-xs); }
.mt-2 { margin-top: var(--spacing-sm); }
.mt-3 { margin-top: var(--spacing-md); }
.mt-4 { margin-top: var(--spacing-lg); }
.mt-5 { margin-top: var(--spacing-xl); }

.d-none { display: none; }
.d-block { display: block; }
.d-flex { display: flex; }
.d-grid { display: grid; }

.fade-in {
    animation: fadeIn 0.5s ease-in;
}

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