:root {
    --primary: #4361ee;
    --primary-dark: #3a56d4;
    --secondary: #4cc9f0;
    --dark: #1c1c1c;
    --light: #f8f9fa;
    --gray: #6c757d;
    --success: #4caf50;
    --warning: #ff9800;
    --danger: #f44336;
    --text-primary: #333;
    --text-secondary: #666;
    --border: #dee2e6;
    --shadow: rgba(0, 0, 0, 0.1);
    --radius: 8px;
    --transition: all 0.3s ease;
}

/* Dark mode variables */
body.dark-theme {
    --primary: #5a7dff;
    --secondary: #6dd6f3;
    --dark: #f8f9fa;
    --light: #1a1a1a;
    --text-primary: #f0f0f0;
    --text-secondary: #bbb;
    --border: #444;
    --shadow: rgba(0, 0, 0, 0.3);
    --card-bg: #2d2d2d;
    --modal-bg: #333;
    --input-bg: #2a2a2a;
}

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

body {
    font-family: 'Inter', sans-serif;
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--light);
    transition: background-color 0.3s ease, color 0.3s ease;
}

.container {
    width: 90%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 15px;
}

/* Header Styles */
.header {
    background-color: var(--light);
    box-shadow: 0 2px 10px var(--shadow);
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 1000;
    transition: background-color 0.3s ease, box-shadow 0.3s ease;
}

.navbar {
    padding: 1rem 0;
}

.nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 15px;
}

.nav-brand {
    display: flex;
    align-items: center;
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary);
}

.nav-brand i {
    margin-right: 10px;
}

.nav-search {
    position: relative;
    width: 40%;
}

.search-input {
    width: 100%;
    padding: 10px 15px 10px 40px;
    border: 1px solid var(--border);
    border-radius: 30px;
    font-size: 0.9rem;
    transition: var(--transition);
    background-color: var(--light);
    color: var(--text-primary);
}

.search-input:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(67, 97, 238, 0.2);
}

.search-icon {
    position: absolute;
    left: 15px;
    top: 50%;
    transform: translateY(-50%);
    color: var(--gray);
}

.nav-actions {
    display: flex;
    gap: 15px;
}

.btn-theme, .btn-menu {
    background: none;
    border: none;
    font-size: 1.2rem;
    cursor: pointer;
    color: var(--text-primary);
    transition: var(--transition);
    width: 40px;
    height: 40px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
}

.btn-theme:hover, .btn-menu:hover {
    background-color: rgba(0, 0, 0, 0.1);
    color: var(--primary);
}

/* Hero Section */
.hero {
    padding: 150px 0 100px;
    background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
    color: white;
    position: relative;
    overflow: hidden;
}

.hero-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 15px;
}

.hero-content {
    flex: 1;
    padding-right: 50px;
}

.hero-title {
    font-size: 3rem;
    margin-bottom: 20px;
    line-height: 1.2;
}

.gradient-text {
    background: linear-gradient(90deg, #fff 0%, #f0f0f0 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-description {
    font-size: 1.2rem;
    margin-bottom: 30px;
    opacity: 0.9;
}

.hero-description strong {
    font-weight: 600;
}

.hero-description em {
    font-style: italic;
}

.hero-stats {
    display: flex;
    gap: 30px;
    margin-bottom: 30px;
}

.stat {
    text-align: center;
}

.stat-number {
    font-size: 2rem;
    font-weight: 700;
    display: block;
}

.stat-label {
    font-size: 0.9rem;
    opacity: 0.9;
}

.hero-visual {
    flex: 1;
    text-align: center;
}

.hero-icon {
    font-size: 10rem;
    opacity: 0.2;
}

.converter-tag {
    background: rgba(255, 255, 255, 0.2);
    padding: 5px 15px;
    border-radius: 20px;
    font-size: 0.9rem;
    cursor: pointer;
    transition: var(--transition);
}

.converter-tag:hover {
    background: rgba(255, 255, 255, 0.3);
}

/* Categories Section */
.categories {
    padding: 100px 0;
    background-color: var(--light);
    transition: background-color 0.3s ease;
}

.section-header {
    text-align: center;
    margin-bottom: 50px;
}

.section-title {
    font-size: 2.5rem;
    color: var(--text-primary);
    margin-bottom: 15px;
}

.section-description {
    font-size: 1.1rem;
    color: var(--text-secondary);
    max-width: 700px;
    margin: 0 auto;
}

.categories-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 30px;
}

.category-card {
    background: var(--light);
    border-radius: var(--radius);
    overflow: hidden;
    box-shadow: 0 5px 15px var(--shadow);
    transition: var(--transition);
}

.category-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 15px 30px rgba(0, 0, 0, 0.15);
}

.category-header {
    padding: 20px;
    background: linear-gradient(90deg, var(--primary) 0%, var(--secondary) 100%);
    color: white;
    display: flex;
    align-items: center;
    gap: 15px;
}

.category-icon {
    font-size: 1.5rem;
}

.category-title {
    font-size: 1.5rem;
    margin: 0;
}

.category-content {
    padding: 20px;
}

.category-description {
    color: var(--text-secondary);
    margin-bottom: 20px;
}

.converter-buttons {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 10px;
}

.btn-converter {
    background: var(--light);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 12px;
    text-align: center;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
    font-size: 0.85rem;
    color: var(--text-primary);
}

.btn-converter:hover {
    border-color: var(--primary);
    color: var(--primary);
    transform: translateY(-3px);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
}

.btn-converter i {
    font-size: 1.2rem;
}

/* Modal Styles */
.modal {
    display: none;
    position: fixed;
    z-index: 1001;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    overflow: auto;
}

.modal-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
}

.modal-content {
    background-color: var(--light);
    margin: 5% auto;
    padding: 0;
    border-radius: var(--radius);
    width: 90%;
    max-width: 800px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
    position: relative;
    animation: slideIn 0.3s ease;
    color: var(--text-primary);
    max-height: 80vh;
    display: flex;
    flex-direction: column;
}

.modal-header {
    padding: 20px;
    background: linear-gradient(90deg, var(--primary) 0%, var(--secondary) 100%);
    color: white;
    border-radius: var(--radius) var(--radius) 0 0;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.modal-title {
    margin: 0;
    font-size: 1.5rem;
}

.modal-close {
    background: none;
    border: none;
    color: white;
    font-size: 1.5rem;
    cursor: pointer;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
}

.modal-close:hover {
    background: rgba(255, 255, 255, 0.2);
}

.modal-body {
    padding: 20px;
    min-height: 200px;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow-y: auto;
    flex: 1;
}

.development-message {
    text-align: center;
    padding: 30px;
    color: var(--text-secondary);
}

.development-message i {
    margin-bottom: 20px;
    color: var(--primary);
}

.development-message h3 {
    margin-bottom: 15px;
    color: var(--text-primary);
}

.modal-footer {
    padding: 20px;
    border-top: 1px solid var(--border);
    display: flex;
    justify-content: space-between;
    flex-shrink: 0;
}

.btn {
    padding: 12px 20px;
    border-radius: var(--radius);
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    border: none;
    font-size: 0.9rem;
    display: flex;
    align-items: center;
    gap: 8px;
}

.btn-primary {
    background: linear-gradient(90deg, var(--primary) 0%, var(--secondary) 100%);
    color: white;
}

.btn-primary:hover {
    opacity: 0.9;
    transform: translateY(-2px);
}

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

.btn-secondary:hover {
    background: #e9ecef;
    transform: translateY(-2px);
}

/* Converter Form Styles */
.converter-form {
    width: 100%;
    max-width: 100%;
    margin: 0 auto;
    padding: 20px;
    display: flex;
    flex-wrap: wrap;
    gap: 20px;
}

.input-group {
    margin-bottom: 20px;
    flex: 1 1 200px;
}

.input-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500;
    color: var(--text-primary);
}

.input-group input,
.input-group select {
    width: 100%;
    padding: 12px;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    font-size: 1rem;
    transition: var(--transition);
    background-color: var(--light);
    color: var(--text-primary);
    min-width: 150px;
}

.input-group input:focus,
.input-group select:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(67, 97, 238, 0.2);
}

.btn {
    padding: 12px 20px;
    border-radius: var(--radius);
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    border: none;
    font-size: 1rem;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
}

.btn-primary {
    background: linear-gradient(90deg, var(--primary) 0%, var(--secondary) 100%);
    color: white;
    width: 100%;
}

.btn-primary:hover {
    opacity: 0.9;
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
}

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

.btn-secondary:hover {
    background: #e9ecef;
    transform: translateY(-2px);
}

.result-container {
    margin-top: 20px;
    padding: 20px;
    background: var(--light);
    border-radius: var(--radius);
    text-align: center;
    display: none;
    min-width: 100%;
}

.result-container:not(:empty) {
    display: block;
}

.result-value {
    font-size: 1.4rem;
    font-weight: 700;
    color: var(--primary);
    margin-bottom: 10px;
}

.conversion-details {
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.error {
    color: var(--danger);
    font-weight: 500;
    padding: 10px;
    border-radius: var(--radius);
    background-color: #ffe8e8;
}

/* Dark mode converter form styles */
body.dark-theme .converter-form input,
body.dark-theme .converter-form select {
    background-color: var(--input-bg);
    border: 1px solid var(--border);
    color: var(--text-primary);
}

body.dark-theme .converter-form input:focus,
body.dark-theme .converter-form select:focus {
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(67, 97, 238, 0.2);
}

body.dark-theme .result-container {
    background: var(--card-bg);
}

body.dark-theme .btn-secondary {
    background: var(--card-bg);
    border: 1px solid var(--border);
}

/* Loading Screen */
.loading-screen {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(255, 255, 255, 0.9);
    z-index: 1002;
    justify-content: center;
    align-items: center;
}

.loading-content {
    text-align: center;
}

.loading-spinner {
    width: 50px;
    height: 50px;
    border: 5px solid var(--light);
    border-top: 5px solid var(--primary);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin: 0 auto 20px;
}

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

/* Footer */
.footer {
    background-color: var(--dark);
    color: #fff;
    padding: 70px 0 0;
    transition: background-color 0.3s ease;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 40px;
    margin-bottom: 50px;
}

.footer-brand .brand {
    display: flex;
    align-items: center;
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 20px;
    color: var(--secondary);
}

.footer-brand .brand i {
    margin-right: 10px;
}

.footer-brand p {
    color: #aaa;
    margin-bottom: 20px;
    line-height: 1.8;
}

.footer-links {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 30px;
}

.link-group h4 {
    font-size: 1.1rem;
    margin-bottom: 20px;
    position: relative;
    padding-bottom: 10px;
    color: var(--secondary);
}

.link-group h4::after {
    content: "";
    position: absolute;
    bottom: 0;
    left: 0;
    width: 30px;
    height: 2px;
    background: var(--primary);
}

.link-group ul {
    list-style: none;
}

.link-group ul li {
    padding: 8px 0;
}

.link-group ul li a {
    color: #aaa;
    text-decoration: none;
    transition: var(--transition);
    font-size: 0.9rem;
}

.link-group ul li a:hover {
    color: var(--secondary);
    padding-left: 5px;
}

.footer-bottom {
    text-align: center;
    padding: 20px 0;
    border-top: 1px solid #333;
    color: #aaa;
    font-size: 0.9rem;
}

.footer-bottom a {
    color: #aaa;
    text-decoration: none;
    margin: 0 10px;
    transition: var(--transition);
}

.footer-bottom a:hover {
    color: var(--secondary);
}

/* Animations */
@keyframes slideIn {
    from {
        transform: translateY(-50px);
        opacity: 0;
    }
    to {
        transform: translateY(0);
        opacity: 1;
    }
}

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

/* Notifications */
.notification {
    position: fixed;
    top: 20px;
    right: 20px;
    padding: 15px 20px;
    border-radius: var(--radius);
    color: white;
    font-weight: 500;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
    z-index: 9999;
    display: flex;
    align-items: center;
    gap: 10px;
    transform: translateX(100%);
    animation: slideInRight 0.3s forwards;
    transition: transform 0.3s ease;
}

@keyframes slideInRight {
    to {
        transform: translateX(0);
    }
}

.notification-hide {
    animation: slideOutRight 0.3s forwards;
}

@keyframes slideOutRight {
    to {
        transform: translateX(100%);
    }
}

.notification-close {
    background: none;
    border: none;
    color: white;
    cursor: pointer;
    font-size: 1.2rem;
    padding: 0;
    margin-left: 10px;
}

.notification-close:hover {
    opacity: 0.8;
}

.notification-info {
    background: var(--primary);
}

.notification-success {
    background: var(--success);
}

.notification-warning {
    background: var(--warning);
}

.notification-error {
    background: var(--danger);
}

/* Dark mode notifications */
body.dark-theme .notification {
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
}

/* Responsive Design */
@media (max-width: 992px) {
    .hero-container {
        flex-direction: column;
        text-align: center;
    }
    
    .hero-content {
        padding-right: 0;
        margin-bottom: 50px;
    }
    
    .hero-stats {
        justify-content: center;
    }
    
    .section-title {
        font-size: 2rem;
    }
    
    .nav-search {
        width: 30%;
    }
    
    .converter-form {
        flex-direction: column;
    }
    
    .input-group {
        flex: 1 1 auto;
    }
}

@media (max-width: 768px) {
    .navbar {
        padding: 15px 0;
    }
    
    .nav-container {
        flex-direction: column;
        gap: 15px;
    }
    
    .nav-search {
        width: 100%;
    }
    
    .hero {
        padding: 120px 0 80px;
    }
    
    .hero-title {
        font-size: 2.2rem;
    }
    
    .hero-description {
        font-size: 1rem;
    }
    
    .hero-stats {
        flex-direction: column;
        gap: 20px;
    }
    
    .section-title {
        font-size: 1.8rem;
    }
    
    .categories-grid {
        grid-template-columns: 1fr;
    }
    
    .converter-buttons {
        grid-template-columns: 1fr;
    }
    
    .notification {
        right: 10px;
        left: 10px;
        width: auto;
    }
    
    .modal-content {
        width: 95%;
        max-height: 90vh;
    }
    
    .converter-form {
        padding: 10px;
    }
}

@media (max-width: 576px) {
    .container {
        width: 95%;
    }
    
    .hero-title {
        font-size: 1.8rem;
    }
    
    .section-title {
        font-size: 1.5rem;
    }
    
    .category-header {
        padding: 15px;
    }
    
    .category-content {
        padding: 15px;
    }
    
    .modal-content {
        margin: 10% auto;
        width: 95%;
        max-height: 95vh;
    }
    
    .converter-form {
        flex-direction: column;
    }
    
    .input-group {
        min-width: 100%;
    }
}

/* Dark mode specific styles */
body.dark-theme .category-card {
    background: var(--card-bg);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.3);
}

body.dark-theme .btn-converter {
    background: var(--card-bg);
    border-color: var(--border);
}

body.dark-theme .btn-secondary {
    background: var(--card-bg);
    border: 1px solid var(--border);
}

body.dark-theme .search-input {
    background-color: var(--input-bg);
    border: 1px solid var(--border);
}

body.dark-theme .loading-screen {
    background: rgba(0, 0, 0, 0.9);
}

body.dark-theme .loading-spinner {
    border: 5px solid var(--input-bg);
    border-top: 5px solid var(--primary);
}

body.dark-theme .modal-content {
    background-color: var(--modal-bg);
}

body.dark-theme .modal-footer {
    border-top: 1px solid var(--border);
}

body.dark-theme .converter-form input,
body.dark-theme .converter-form select {
    background-color: var(--input-bg);
    border: 1px solid var(--border);
    color: var(--text-primary);
}

body.dark-theme .converter-form input:focus,
body.dark-theme .converter-form select:focus {
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(67, 97, 238, 0.2);
}

body.dark-theme .result-container {
    background: var(--card-bg);
}

/* User Widget Styles */
.user-widget {
    display: flex;
    align-items: center;
    background-color: rgba(67, 97, 238, 0.1);
    border-radius: 20px;
    padding: 5px 12px;
    margin-right: 10px;
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--primary);
    transition: var(--transition);
}

.user-widget:hover {
    background-color: rgba(67, 97, 238, 0.2);
    transform: translateY(-2px);
}

.user-widget-content {
    display: flex;
    align-items: center;
    gap: 5px;
}

.user-widget i {
    font-size: 0.9rem;
}

.user-count {
    font-weight: 600;
}

.user-label {
    color: var(--text-secondary);
    font-size: 0.8rem;
}

/* Dark mode user widget */
body.dark-theme .user-widget {
    background-color: rgba(90, 125, 255, 0.15);
    color: var(--primary);
}

body.dark-theme .user-widget:hover {
    background-color: rgba(90, 125, 255, 0.25);
}