/* CSS Variables */
:root {
    --primary-color: #0066cc;
    --secondary-color: #00a86b;
    --accent-color: #ff6b6b;
    --bg-light: #f8fafc;
    --bg-white: #ffffff;
    --text-dark: #1a202c;
    --text-gray: #718096;
    --border-color: #e2e8f0;
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.1);
    --radius: 8px;
    --radius-lg: 12px;
    --transition: all 0.3s ease;
}

body.dark-mode {
    --bg-light: #1a202c;
    --bg-white: #2d3748;
    --text-dark: #f7fafc;
    --text-gray: #cbd5e0;
    --border-color: #4a5568;
}

/* Reset & Base */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background-color: var(--bg-light);
    color: var(--text-dark);
    line-height: 1.6;
    transition: var(--transition);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Header */
.header {
    background-color: var(--bg-white);
    box-shadow: var(--shadow-sm);
    position: sticky;
    top: 0;
    z-index: 100;
    transition: var(--transition);
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 0;
}

.logo h1 {
    font-size: 1.5rem;
    color: var(--primary-color);
}

.nav {
    display: flex;
    gap: 0;
    flex-wrap: wrap;
    align-items: center;
}

.nav-item {
    background: none;
    border: none;
    padding: 0.75rem 1.25rem;
    cursor: pointer;
    color: var(--text-gray);
    font-size: 0.95rem;
    text-decoration: none;
    transition: var(--transition);
    display: flex;
    align-items: center;
}

.nav-item:hover {
    color: var(--primary-color);
    background-color: rgba(0, 102, 204, 0.05);
}

.nav-dropdown {
    position: relative;
}

.dropdown-toggle {
    padding: 0.75rem 1.25rem !important;
}

.dropdown-menu {
    position: absolute;
    top: 100%;
    left: 0;
    background-color: var(--bg-white);
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    box-shadow: var(--shadow-lg);
    min-width: 250px;
    display: none;
    flex-direction: column;
    z-index: 1000;
}

.nav-dropdown:hover .dropdown-menu {
    display: flex;
}

.dropdown-menu a {
    padding: 0.75rem 1.25rem;
    color: var(--text-dark);
    text-decoration: none;
    transition: var(--transition);
    border-left: 3px solid transparent;
}

.dropdown-menu a:hover {
    background-color: rgba(0, 102, 204, 0.1);
    color: var(--primary-color);
    border-left-color: var(--primary-color);
}

.theme-toggle {
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    padding: 0.5rem;
    transition: var(--transition);
}

.theme-toggle:hover {
    transform: scale(1.1);
}

/* Main Content */
.main-content {
    min-height: calc(100vh - 200px);
    padding: 2rem 0;
}

.view {
    display: none;
}

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

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Hero Section */
.hero {
    text-align: center;
    padding: 3rem 0;
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: white;
    border-radius: var(--radius-lg);
    margin-bottom: 3rem;
}

.hero h2 {
    font-size: 2.5rem;
    margin-bottom: 0.5rem;
}

.hero p {
    font-size: 1.1rem;
    margin-bottom: 2rem;
    opacity: 0.95;
}

.search-box {
    display: flex;
    gap: 0.5rem;
    max-width: 500px;
    margin: 0 auto;
}

.search-box input {
    flex: 1;
    padding: 0.75rem 1rem;
    border: none;
    border-radius: var(--radius);
    font-size: 1rem;
}

.search-btn {
    padding: 0.75rem 1.5rem;
    background-color: var(--accent-color);
    color: white;
    border: none;
    border-radius: var(--radius);
    cursor: pointer;
    font-size: 1rem;
    transition: var(--transition);
}

.search-btn:hover {
    background-color: #ff5252;
}

/* Sections */
.popular-section,
.categories-section,
.info-section,
.category-filter {
    margin-bottom: 3rem;
}

.popular-section h3,
.categories-section h3,
.info-section h3,
.category-filter h3 {
    font-size: 1.5rem;
    margin-bottom: 1.5rem;
    color: var(--text-dark);
}

.info-section {
    background-color: var(--bg-white);
    padding: 2rem;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
}

/* Grid Layouts */
.tools-grid,
.categories-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 1.5rem;
}

@media (max-width: 768px) {
    .tools-grid,
    .categories-grid {
        grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
        gap: 1rem;
    }
}

@media (max-width: 480px) {
    .tools-grid,
    .categories-grid {
        grid-template-columns: 1fr;
    }
}

/* Tool Card */
.tool-card {
    background-color: var(--bg-white);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
    box-shadow: var(--shadow-md);
    cursor: pointer;
    transition: var(--transition);
    border: 2px solid transparent;
}

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

.tool-card h4 {
    font-size: 1.1rem;
    margin-bottom: 0.5rem;
    color: var(--text-dark);
}

.tool-card p {
    font-size: 0.9rem;
    color: var(--text-gray);
    margin-bottom: 1rem;
}

.tool-card-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 0.85rem;
    color: var(--text-gray);
}

.favorite-btn {
    background: none;
    border: none;
    font-size: 1.2rem;
    cursor: pointer;
    transition: var(--transition);
}

.favorite-btn.active {
    color: var(--accent-color);
}

/* Category Card */
.category-card {
    background-color: var(--bg-white);
    border-radius: var(--radius-lg);
    padding: 2rem;
    text-align: center;
    box-shadow: var(--shadow-md);
    cursor: pointer;
    transition: var(--transition);
    border: 2px solid transparent;
}

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

.category-card-icon {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.category-card h4 {
    font-size: 1.1rem;
    color: var(--text-dark);
}

/* Category Buttons */
.category-buttons {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
    margin-bottom: 2rem;
}

.category-btn {
    padding: 0.5rem 1rem;
    border: 2px solid var(--border-color);
    background-color: var(--bg-white);
    color: var(--text-dark);
    border-radius: var(--radius);
    cursor: pointer;
    transition: var(--transition);
    font-size: 0.9rem;
}

.category-btn:hover,
.category-btn.active {
    background-color: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

/* Tool View */
.back-btn {
    background: none;
    border: none;
    color: var(--primary-color);
    font-size: 1rem;
    cursor: pointer;
    padding: 0.5rem 0;
    margin-bottom: 1.5rem;
    transition: var(--transition);
}

.back-btn:hover {
    color: var(--secondary-color);
}

.tool-container {
    background-color: var(--bg-white);
    border-radius: var(--radius-lg);
    padding: 2rem;
    box-shadow: var(--shadow-md);
}

.tool-header {
    margin-bottom: 2rem;
    border-bottom: 2px solid var(--border-color);
    padding-bottom: 1rem;
}

.tool-header h2 {
    font-size: 1.8rem;
    margin-bottom: 0.5rem;
}

.tool-category {
    display: inline-block;
    background-color: var(--primary-color);
    color: white;
    padding: 0.25rem 0.75rem;
    border-radius: var(--radius);
    font-size: 0.85rem;
    margin-top: 0.5rem;
}

.tool-description {
    color: var(--text-gray);
    margin-bottom: 1rem;
}

/* Form Section */
.form-section {
    background-color: var(--bg-light);
    padding: 1.5rem;
    border-radius: var(--radius-lg);
    margin-bottom: 2rem;
}

.form-section h3 {
    font-size: 1.2rem;
    margin-bottom: 1.5rem;
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
    color: var(--text-dark);
}

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 0.75rem;
    border: 2px solid var(--border-color);
    border-radius: var(--radius);
    font-size: 1rem;
    background-color: var(--bg-white);
    color: var(--text-dark);
    transition: var(--transition);
}

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

.form-group input.error,
.form-group select.error {
    border-color: var(--accent-color);
}

.error-message {
    color: var(--accent-color);
    font-size: 0.85rem;
    margin-top: 0.25rem;
}

.form-row {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
}

/* Buttons */
.btn {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: var(--radius);
    font-size: 1rem;
    cursor: pointer;
    transition: var(--transition);
    font-weight: 500;
}

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

.btn-primary:hover {
    background-color: #0052a3;
}

.btn-secondary {
    background-color: var(--text-gray);
    color: white;
}

.btn-secondary:hover {
    background-color: #4a5568;
}

.btn-group {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
    margin-bottom: 2rem;
}

.btn-group .btn {
    flex: 1;
    min-width: 150px;
}

@media (max-width: 480px) {
    .btn-group {
        flex-direction: column;
    }

    .btn-group .btn {
        width: 100%;
    }
}

/* Result Section */
.result-section {
    background: linear-gradient(135deg, var(--secondary-color) 0%, #00d084 100%);
    color: white;
    padding: 2rem;
    border-radius: var(--radius-lg);
    margin-bottom: 2rem;
    display: none;
}

.result-section.show {
    display: block;
    animation: slideIn 0.3s ease;
}

.result-section.error {
    background: linear-gradient(135deg, var(--accent-color) 0%, #ff5252 100%);
}

@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateY(-10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.result-title {
    font-size: 1.2rem;
    margin-bottom: 1rem;
    font-weight: 600;
}

.result-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1.5rem;
}

.result-item {
    background-color: rgba(255, 255, 255, 0.1);
    padding: 1rem;
    border-radius: var(--radius);
}

.result-label {
    font-size: 0.9rem;
    opacity: 0.9;
    margin-bottom: 0.25rem;
}

.result-value {
    font-size: 1.5rem;
    font-weight: 700;
}

.result-actions {
    display: flex;
    gap: 1rem;
    margin-top: 1.5rem;
    flex-wrap: wrap;
}

.result-actions button {
    padding: 0.5rem 1rem;
    background-color: rgba(255, 255, 255, 0.2);
    color: white;
    border: 2px solid white;
    border-radius: var(--radius);
    cursor: pointer;
    transition: var(--transition);
    font-size: 0.9rem;
}

.result-actions button:hover {
    background-color: rgba(255, 255, 255, 0.3);
}

/* Info Sections */
.info-box {
    background-color: var(--bg-light);
    border-left: 4px solid var(--primary-color);
    padding: 1.5rem;
    border-radius: var(--radius);
    margin-bottom: 1.5rem;
}

.info-box h4 {
    margin-bottom: 0.5rem;
    color: var(--text-dark);
}

.info-box p {
    color: var(--text-gray);
    font-size: 0.95rem;
}

.warning-box {
    border-left-color: var(--accent-color);
    background-color: rgba(255, 107, 107, 0.05);
}

.success-box {
    border-left-color: var(--secondary-color);
    background-color: rgba(0, 168, 107, 0.05);
}

/* FAQ Section */
.faq-section {
    margin-top: 2rem;
}

.faq-item {
    background-color: var(--bg-light);
    border-radius: var(--radius);
    margin-bottom: 1rem;
    overflow: hidden;
}

.faq-question {
    padding: 1rem;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-weight: 500;
    transition: var(--transition);
}

.faq-question:hover {
    background-color: var(--border-color);
}

.faq-answer {
    padding: 0 1rem 1rem 1rem;
    color: var(--text-gray);
    display: none;
}

.faq-answer.show {
    display: block;
}

.faq-toggle {
    font-size: 1.2rem;
    transition: var(--transition);
}

.faq-toggle.open {
    transform: rotate(180deg);
}

/* Table */
.table-responsive {
    overflow-x: auto;
    margin-bottom: 2rem;
}

table {
    width: 100%;
    border-collapse: collapse;
    background-color: var(--bg-white);
    border-radius: var(--radius);
    overflow: hidden;
}

th {
    background-color: var(--primary-color);
    color: white;
    padding: 1rem;
    text-align: left;
    font-weight: 600;
}

td {
    padding: 0.75rem 1rem;
    border-bottom: 1px solid var(--border-color);
}

tr:hover {
    background-color: var(--bg-light);
}

/* Footer */
.footer {
    background-color: var(--bg-white);
    border-top: 1px solid var(--border-color);
    padding: 3rem 0 1rem;
    margin-top: 3rem;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-bottom: 2rem;
}

.footer-section h4 {
    margin-bottom: 1rem;
    color: var(--text-dark);
}

.footer-section p {
    color: var(--text-gray);
    font-size: 0.9rem;
    line-height: 1.6;
}

.footer-section ul {
    list-style: none;
}

.footer-section ul li {
    margin-bottom: 0.5rem;
}

.footer-section ul a {
    color: var(--text-gray);
    text-decoration: none;
    transition: var(--transition);
}

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

.footer-bottom {
    border-top: 1px solid var(--border-color);
    padding-top: 1.5rem;
    text-align: center;
    color: var(--text-gray);
    font-size: 0.9rem;
}

.footer-bottom p {
    margin-bottom: 0.5rem;
}

.disclaimer {
    font-size: 0.85rem;
    font-style: italic;
}

/* Empty State */
.empty-message {
    text-align: center;
    color: var(--text-gray);
    padding: 3rem 1rem;
    font-size: 1.1rem;
}

/* Responsive */
@media (max-width: 768px) {
    .hero {
        padding: 2rem 1rem;
    }

    .hero h2 {
        font-size: 1.8rem;
    }

    .hero p {
        font-size: 1rem;
    }

    .tool-header h2 {
        font-size: 1.5rem;
    }

    .nav {
        gap: 0.5rem;
    }

    .nav-btn {
        padding: 0.5rem 0.75rem;
        font-size: 0.85rem;
    }

    .result-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    .header-content {
        flex-direction: column;
        gap: 1rem;
    }

    .logo h1 {
        font-size: 1.2rem;
    }

    .nav {
        width: 100%;
        justify-content: center;
    }

    .hero h2 {
        font-size: 1.5rem;
    }

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

    .tool-container {
        padding: 1rem;
    }

    .form-section {
        padding: 1rem;
    }

    .btn-group {
        gap: 0.5rem;
    }
}

/* Breadcrumb */
.breadcrumb {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-bottom: 2rem;
    font-size: 0.9rem;
    color: var(--text-gray);
}

.breadcrumb a {
    color: var(--primary-color);
    text-decoration: none;
    transition: var(--transition);
}

.breadcrumb a:hover {
    text-decoration: underline;
}

.breadcrumb span {
    color: var(--text-gray);
}

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

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

.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }
.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }