:root {
    --primary: #1e3a5f;
    --primary-light: #2d5a8a;
    --secondary: #f57c00;
    --accent: #00acc1;
    --bg-primary: #ffffff;
    --bg-secondary: #f8fafc;
    --text-primary: #1a1a2e;
    --text-secondary: #64748b;
    --border: #e2e8f0;
    --success: #22c55e;
    --card-shadow: 0 4px 6px -1px rgba(0,0,0,0.1);
}

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

body {
    font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
    background: var(--bg-secondary);
    color: var(--text-primary);
    line-height: 1.6;
}

a { color: inherit; text-decoration: none; }

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

/* Header */
.header {
    background: var(--primary);
    color: white;
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

.header .container {
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 1.5rem;
    font-weight: 700;
    color: white;
}

.logo-icon {
    width: 40px;
    height: 40px;
    background: var(--secondary);
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
}

.nav {
    display: flex;
    gap: 8px;
}

.nav-link {
    padding: 8px 16px;
    border-radius: 6px;
    transition: all 0.2s;
    font-weight: 500;
    color: rgba(255,255,255,0.85);
}

.nav-link:hover, .nav-link.active {
    background: rgba(255,255,255,0.15);
    color: white;
}

.mobile-menu-btn {
    display: none;
    background: none;
    border: none;
    color: white;
    cursor: pointer;
    padding: 8px;
}

/* Page Header */
.page-header {
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-light) 100%);
    color: white;
    padding: 60px 0;
    text-align: center;
}

.page-header h1 {
    font-size: 2.5rem;
    margin-bottom: 10px;
}

.page-header p {
    opacity: 0.9;
    font-size: 1.1rem;
}

/* Section */
.section {
    padding: 60px 0;
}

/* Cards */
.card {
    background: white;
    border-radius: 12px;
    padding: 24px;
    box-shadow: var(--card-shadow);
    transition: transform 0.2s, box-shadow 0.2s;
}

.card:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 25px -5px rgba(0,0,0,0.1);
}

/* Tools Grid */
.tools-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 24px;
}

.tool-card {
    display: block;
    padding: 28px;
    text-align: center;
    transition: all 0.3s;
    border: 2px solid transparent;
}

.tool-card:hover {
    border-color: var(--secondary);
    transform: translateY(-4px);
}

.tool-icon {
    width: 64px;
    height: 64px;
    margin: 0 auto 16px;
    border-radius: 16px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 28px;
}

.tool-card h3 {
    margin-bottom: 8px;
    color: var(--primary);
}

.tool-card p {
    color: var(--text-secondary);
    font-size: 14px;
}

.tool-tag {
    display: inline-block;
    background: var(--secondary);
    color: white;
    padding: 4px 10px;
    border-radius: 20px;
    font-size: 11px;
    margin-top: 10px;
}

/* Articles Grid */
.articles-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
    gap: 24px;
}

.article-card {
    background: white;
    border-radius: 12px;
    overflow: hidden;
    box-shadow: var(--card-shadow);
    transition: transform 0.2s;
    display: flex;
    flex-direction: column;
}

.article-card:hover {
    transform: translateY(-4px);
}

.article-card img {
    width: 100%;
    height: 200px;
    object-fit: cover;
}

.article-info {
    padding: 20px;
    flex: 1;
    display: flex;
    flex-direction: column;
}

.article-category {
    display: inline-block;
    background: var(--primary);
    color: white;
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 12px;
    margin-bottom: 10px;
    width: fit-content;
}

.article-card h3 {
    color: var(--primary);
    margin-bottom: 8px;
    font-size: 1.1rem;
}

.article-card p {
    color: var(--text-secondary);
    font-size: 14px;
    flex: 1;
}

.article-meta {
    display: flex;
    gap: 16px;
    margin-top: 12px;
    padding-top: 12px;
    border-top: 1px solid var(--border);
    font-size: 12px;
    color: var(--text-secondary);
}

/* Article Content */
.article-content {
    padding: 40px 0;
}

.article-content img {
    border-radius: 12px;
    margin-bottom: 30px;
}

.article-content p {
    margin-bottom: 20px;
    font-size: 17px;
    line-height: 1.8;
}

.article-content h2 {
    color: var(--primary);
    margin: 40px 0 20px;
    font-size: 1.8rem;
}

.article-content h3 {
    color: var(--primary);
    margin: 30px 0 15px;
    font-size: 1.4rem;
}

.lead {
    font-size: 20px;
    color: var(--text-secondary);
    margin-bottom: 30px;
    line-height: 1.7;
}

.article-tags {
    margin-top: 40px;
    padding-top: 20px;
    border-top: 1px solid var(--border);
}

.tag {
    display: inline-block;
    background: var(--bg-secondary);
    color: var(--text-secondary);
    padding: 6px 14px;
    border-radius: 20px;
    font-size: 13px;
    margin-right: 8px;
    margin-bottom: 8px;
}

/* Related Articles */
.related-articles {
    background: var(--bg-secondary);
    padding: 60px 0;
}

/* Footer */
.footer {
    background: var(--primary);
    color: white;
    padding: 60px 0 20px;
}

.footer-grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: 40px;
    margin-bottom: 40px;
}

.footer-links h4 {
    margin-bottom: 16px;
    color: var(--secondary);
}

.footer-links a {
    display: block;
    padding: 6px 0;
    opacity: 0.8;
    transition: opacity 0.2s;
}

.footer-links a:hover {
    opacity: 1;
}

.footer-bottom {
    border-top: 1px solid rgba(255,255,255,0.1);
    padding-top: 20px;
    text-align: center;
    opacity: 0.7;
}

/* Forms */
.form-group {
    margin-bottom: 20px;
}

.form-label {
    display: block;
    margin-bottom: 8px;
    font-weight: 600;
    color: var(--text-primary);
}

.form-input, .form-select, .form-textarea {
    width: 100%;
    padding: 12px 16px;
    border: 2px solid var(--border);
    border-radius: 8px;
    font-size: 15px;
    transition: border-color 0.2s;
    font-family: inherit;
}

.form-input:focus, .form-select:focus, .form-textarea:focus {
    outline: none;
    border-color: var(--primary);
}

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

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 12px 24px;
    border-radius: 8px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s;
    border: none;
    font-size: 15px;
}

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

.btn-primary:hover {
    background: var(--primary-light);
}

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

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

/* About Grid */
.about-grid {
    display: grid;
    grid-template-columns: 1fr 1.5fr;
    gap: 60px;
    align-items: center;
}

.about-grid img {
    border-radius: 16px;
    width: 100%;
}

/* Stats */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 24px;
    margin: 40px 0;
}

.stat-card {
    text-align: center;
    padding: 30px;
    background: white;
    border-radius: 12px;
    box-shadow: var(--card-shadow);
}

.stat-number {
    font-size: 3rem;
    font-weight: 700;
    color: var(--primary);
}

.stat-label {
    color: var(--text-secondary);
    margin-top: 8px;
}

/* Responsive */
@media (max-width: 768px) {
    .nav { display: none; }
    .mobile-menu-btn { display: block; }
    .nav.mobile-open {
        display: flex;
        flex-direction: column;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: var(--primary);
        padding: 20px;
    }
    .footer-grid { grid-template-columns: 1fr; }
    .about-grid { grid-template-columns: 1fr; }
    .stats-grid { grid-template-columns: repeat(2, 1fr); }
    .tools-grid, .articles-grid { grid-template-columns: 1fr; }
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-light) 100%);
    color: white;
    padding: 80px 0;
    text-align: center;
}

.hero h1 {
    font-size: 3rem;
    margin-bottom: 20px;
}

.hero p {
    font-size: 1.2rem;
    opacity: 0.9;
    max-width: 600px;
    margin: 0 auto 30px;
}

.hero-buttons {
    display: flex;
    gap: 16px;
    justify-content: center;
}

/* Mobile menu */
.mobile-menu-btn {
    background: none;
    border: none;
    color: white;
    cursor: pointer;
}