/* ==================== */
/* CSS Variables */
/* ==================== */

:root {
    /* Light mode colors */
    --bg-primary: #ffffff;
    --bg-secondary: #f5f5f5;
    --bg-code: #f8f9fa;
    --text-primary: #333333;
    --text-secondary: #666666;
    --text-muted: #999999;
    --border-color: #e0e0e0;
    --link-color: #0066cc;
    --link-hover: #004999;
    --header-bg: #ffffff;
    --footer-bg: #222222;
    --footer-text: #cccccc;
    --accent-color: #0066cc;
    --code-text: #d63384;
    --badge-bg: #e7f3ff;
    --badge-text: #0066cc;

    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;

    /* Typography */
    --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    --font-mono: 'Consolas', 'Monaco', 'Courier New', monospace;
}

[data-theme="dark"] {
    --bg-primary: #1a1a1a;
    --bg-secondary: #2d2d2d;
    --bg-code: #2d2d2d;
    --text-primary: #e0e0e0;
    --text-secondary: #b0b0b0;
    --text-muted: #808080;
    --border-color: #404040;
    --link-color: #4da6ff;
    --link-hover: #80bfff;
    --header-bg: #1a1a1a;
    --footer-bg: #0d0d0d;
    --footer-text: #b0b0b0;
    --accent-color: #4da6ff;
    --code-text: #ff6b9d;
    --badge-bg: #1a3a52;
    --badge-text: #4da6ff;
}

/* ==================== */
/* Reset & Base Styles */
/* ==================== */

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family);
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    transition: background-color 0.3s ease, color 0.3s ease;
}

/* ==================== */
/* Typography */
/* ==================== */

h1, h2, h3, h4, h5, h6 {
    margin-top: var(--spacing-md);
    margin-bottom: var(--spacing-sm);
    font-weight: 600;
    line-height: 1.3;
}

h1 { font-size: 2.5rem; }
h2 { font-size: 2rem; }
h3 { font-size: 1.5rem; }
h4 { font-size: 1.25rem; }
h5 { font-size: 1.1rem; }
h6 { font-size: 1rem; }

p {
    margin-bottom: var(--spacing-sm);
}

a {
    color: var(--link-color);
    text-decoration: none;
    transition: color 0.2s ease;
}

a:hover {
    color: var(--link-hover);
}

/* ==================== */
/* Header & Navigation */
/* ==================== */

.site-header {
    background-color: var(--header-bg);
    border-bottom: 1px solid var(--border-color);
    padding: var(--spacing-sm) 0;
    position: sticky;
    top: 0;
    z-index: 100;
    transition: background-color 0.3s ease;
}

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

.nav-brand a {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: var(--spacing-md);
    align-items: center;
}

.nav-menu a {
    color: var(--text-secondary);
    font-weight: 500;
    transition: color 0.2s ease;
}

.nav-menu a:hover {
    color: var(--accent-color);
}

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 4px;
    background: none;
    border: none;
    cursor: pointer;
}

.nav-toggle span {
    display: block;
    width: 25px;
    height: 3px;
    background-color: var(--text-primary);
    transition: all 0.3s ease;
}

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

.lang-switcher {
    display: flex;
    align-items: center;
    gap: 2px;
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    padding: 2px;
}

.lang-btn {
    display: block;
    padding: 0.2rem 0.5rem;
    font-size: 0.78rem;
    font-weight: 600;
    color: var(--text-secondary);
    border-radius: 4px;
    text-decoration: none;
    transition: all 0.2s ease;
    letter-spacing: 0.03em;
}

.lang-btn:hover {
    color: var(--accent-color);
    background-color: var(--bg-primary);
}

.lang-btn.active {
    background-color: var(--accent-color);
    color: #ffffff;
}

.lang-btn.active:hover {
    color: #ffffff;
    background-color: var(--link-hover);
}

.theme-toggle {
    background: none;
    border: 2px solid var(--border-color);
    border-radius: 50%;
    width: 40px;
    height: 40px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.3s ease;
}

.theme-toggle:hover {
    border-color: var(--accent-color);
}

.theme-icon {
    display: block;
    width: 20px;
    height: 20px;
    background-size: contain;
    background-repeat: no-repeat;
    background-position: center;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%23333333' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Ccircle cx='12' cy='12' r='5'/%3E%3Cline x1='12' y1='1' x2='12' y2='3'/%3E%3Cline x1='12' y1='21' x2='12' y2='23'/%3E%3Cline x1='4.22' y1='4.22' x2='5.64' y2='5.64'/%3E%3Cline x1='18.36' y1='18.36' x2='19.78' y2='19.78'/%3E%3Cline x1='1' y1='12' x2='3' y2='12'/%3E%3Cline x1='21' y1='12' x2='23' y2='12'/%3E%3Cline x1='4.22' y1='19.78' x2='5.64' y2='18.36'/%3E%3Cline x1='18.36' y1='5.64' x2='19.78' y2='4.22'/%3E%3C/svg%3E");
}

[data-theme="dark"] .theme-icon {
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%23e0e0e0' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='M21 12.79A9 9 0 1 1 11.21 3 7 7 0 0 0 21 12.79z'/%3E%3C/svg%3E");
}

/* ==================== */
/* Main Container */
/* ==================== */

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--spacing-lg) var(--spacing-md);
    min-height: calc(100vh - 200px);
}

/* ==================== */
/* Hero Section */
/* ==================== */

.hero {
    text-align: center;
    padding: var(--spacing-xl) 0;
}

.hero h1 {
    font-size: 3rem;
    margin-bottom: var(--spacing-sm);
}

.hero .tagline {
    font-size: 1.3rem;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-md);
}

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

/* ==================== */
/* Sections */
/* ==================== */

.section {
    margin: var(--spacing-xl) 0;
}

.section-title {
    text-align: center;
    margin-bottom: var(--spacing-lg);
    position: relative;
}

.section-title::after {
    content: '';
    display: block;
    width: 60px;
    height: 3px;
    background-color: var(--accent-color);
    margin: var(--spacing-sm) auto 0;
}

/* ==================== */
/* Skills Grid */
/* ==================== */

.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-md);
    margin-top: var(--spacing-lg);
}

.skill-card {
    background-color: var(--bg-secondary);
    padding: var(--spacing-md);
    border-radius: 8px;
    border: 1px solid var(--border-color);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.skill-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

.skill-card h3 {
    margin-top: 0;
    color: var(--accent-color);
}

/* ==================== */
/* Projects Grid */
/* ==================== */

.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-lg);
    margin-top: var(--spacing-lg);
}

.project-card {
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: var(--spacing-md);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.project-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 6px 16px rgba(0, 0, 0, 0.15);
}

.project-card h3 {
    margin-top: 0;
}

.project-links {
    margin-top: var(--spacing-sm);
    display: flex;
    gap: var(--spacing-sm);
}

.btn {
    display: inline-block;
    padding: 0.5rem 1rem;
    background-color: var(--accent-color);
    color: white;
    border-radius: 4px;
    text-decoration: none;
    transition: background-color 0.2s ease;
}

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

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

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

/* ==================== */
/* Knowledge Base */
/* ==================== */

.kb-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-md);
    margin-top: var(--spacing-lg);
}

.kb-category {
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: var(--spacing-md);
}

.kb-category h3 {
    margin-top: 0;
    color: var(--accent-color);
    font-size: 1.3rem;
}

.kb-category ul {
    list-style: none;
    padding: 0;
}

.kb-category li {
    margin: var(--spacing-xs) 0;
    padding: var(--spacing-xs) 0;
    border-bottom: 1px solid var(--border-color);
}

.kb-category li:last-child {
    border-bottom: none;
}

.search-box {
    max-width: 600px;
    margin: 0 auto var(--spacing-lg);
}

.search-box input {
    width: 100%;
    padding: var(--spacing-sm);
    font-size: 1rem;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    transition: border-color 0.2s ease;
}

.search-box input:focus {
    outline: none;
    border-color: var(--accent-color);
}

/* ==================== */
/* Article Styles */
/* ==================== */

.kb-article {
    max-width: 800px;
    margin: 0 auto;
}

.article-header {
    margin-bottom: var(--spacing-lg);
}

.breadcrumb {
    font-size: 0.9rem;
    color: var(--text-muted);
    margin-bottom: var(--spacing-sm);
}

.breadcrumb a {
    color: var(--link-color);
}

.article-description {
    font-size: 1.2rem;
    color: var(--text-secondary);
    margin: var(--spacing-sm) 0;
}

.article-meta {
    display: flex;
    gap: var(--spacing-sm);
    align-items: center;
    flex-wrap: wrap;
    margin-top: var(--spacing-sm);
}

.category-badge {
    background-color: var(--badge-bg);
    color: var(--badge-text);
    padding: 0.25rem 0.75rem;
    border-radius: 4px;
    font-size: 0.85rem;
    font-weight: 600;
}

.date {
    color: var(--text-muted);
    font-size: 0.9rem;
}

.article-content {
    line-height: 1.8;
}

.article-content h2 {
    margin-top: var(--spacing-lg);
    padding-bottom: var(--spacing-xs);
    border-bottom: 2px solid var(--border-color);
}

.article-content h3 {
    margin-top: var(--spacing-md);
}

.article-content ul,
.article-content ol {
    margin-left: var(--spacing-lg);
    margin-bottom: var(--spacing-sm);
}

.article-content li {
    margin: var(--spacing-xs) 0;
}

/* Code Blocks */
.article-content code {
    background-color: var(--bg-code);
    color: var(--code-text);
    padding: 0.2rem 0.4rem;
    border-radius: 3px;
    font-family: var(--font-mono);
    font-size: 0.9em;
}

.article-content pre {
    background-color: var(--bg-code);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    padding: var(--spacing-sm);
    overflow-x: auto;
    margin: var(--spacing-sm) 0;
}

.article-content pre code {
    background: none;
    color: var(--text-primary);
    padding: 0;
}

/* Blockquotes */
.article-content blockquote {
    border-left: 4px solid var(--accent-color);
    padding-left: var(--spacing-sm);
    margin: var(--spacing-sm) 0;
    color: var(--text-secondary);
    font-style: italic;
}

/* Tables */
.article-content table {
    width: 100%;
    border-collapse: collapse;
    margin: var(--spacing-sm) 0;
}

.article-content table th,
.article-content table td {
    border: 1px solid var(--border-color);
    padding: var(--spacing-xs) var(--spacing-sm);
    text-align: left;
}

.article-content table th {
    background-color: var(--bg-secondary);
    font-weight: 600;
}

/* Related Articles */
.related-articles {
    margin-top: var(--spacing-xl);
    padding-top: var(--spacing-lg);
    border-top: 2px solid var(--border-color);
}

.related-articles h3 {
    margin-top: 0;
}

.related-articles ul {
    list-style: none;
    padding: 0;
}

.related-articles li {
    margin: var(--spacing-xs) 0;
}

/* ==================== */
/* Project Page */
/* ==================== */

.project-page {
    max-width: 900px;
    margin: 0 auto;
}

.project-page-header {
    margin-bottom: var(--spacing-xl);
    padding-bottom: var(--spacing-lg);
    border-bottom: 2px solid var(--border-color);
}

.project-page-description {
    font-size: 1.2rem;
    color: var(--text-secondary);
    margin: var(--spacing-sm) 0;
}

.project-page-meta {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    flex-wrap: wrap;
    margin: var(--spacing-sm) 0;
}

.project-status {
    padding: 0.25rem 0.75rem;
    border-radius: 4px;
    font-size: 0.85rem;
    font-weight: 600;
}

.project-status--in-development {
    background-color: #fff3cd;
    color: #856404;
}

.project-status--completed {
    background-color: #d1e7dd;
    color: #0a3622;
}

.project-status--archived {
    background-color: var(--bg-secondary);
    color: var(--text-muted);
    border: 1px solid var(--border-color);
}

[data-theme="dark"] .project-status--in-development {
    background-color: #3d2e00;
    color: #ffc107;
}

[data-theme="dark"] .project-status--completed {
    background-color: #0a2e1a;
    color: #75b798;
}

.project-tech-tags {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-xs);
    margin: var(--spacing-sm) 0;
}

.tech-tag {
    background-color: var(--badge-bg);
    color: var(--badge-text);
    padding: 0.2rem 0.65rem;
    border-radius: 20px;
    font-size: 0.82rem;
    font-weight: 500;
}

.project-page-links {
    display: flex;
    gap: var(--spacing-sm);
    flex-wrap: wrap;
    margin-top: var(--spacing-md);
}

.project-page-content {
    line-height: 1.8;
}

.project-page-content h2 {
    margin-top: var(--spacing-lg);
    padding-bottom: var(--spacing-xs);
    border-bottom: 2px solid var(--border-color);
}

.project-page-content h3 {
    margin-top: var(--spacing-md);
}

.project-page-content ul,
.project-page-content ol {
    margin-left: var(--spacing-lg);
    margin-bottom: var(--spacing-sm);
}

.project-page-content li {
    margin: var(--spacing-xs) 0;
}

.project-page-content code {
    background-color: var(--bg-code);
    color: var(--code-text);
    padding: 0.2rem 0.4rem;
    border-radius: 3px;
    font-family: var(--font-mono);
    font-size: 0.9em;
}

.project-page-content pre {
    background-color: var(--bg-code);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    padding: var(--spacing-sm);
    overflow-x: auto;
    margin: var(--spacing-sm) 0;
}

.project-page-content pre code {
    background: none;
    color: var(--text-primary);
    padding: 0;
}

.project-page-content table {
    width: 100%;
    border-collapse: collapse;
    margin: var(--spacing-sm) 0;
}

.project-page-content table th,
.project-page-content table td {
    border: 1px solid var(--border-color);
    padding: var(--spacing-xs) var(--spacing-sm);
    text-align: left;
}

.project-page-content table th {
    background-color: var(--bg-secondary);
    font-weight: 600;
}

.project-page-content img {
    max-width: 100%;
    border-radius: 8px;
    border: 1px solid var(--border-color);
    margin: var(--spacing-sm) 0;
}

/* ==================== */
/* Contact Section */
/* ==================== */

.contact-links {
    display: flex;
    justify-content: center;
    gap: var(--spacing-md);
    flex-wrap: wrap;
    margin-top: var(--spacing-lg);
}

.contact-btn {
    padding: var(--spacing-sm) var(--spacing-md);
    font-size: 1.1rem;
}

/* ==================== */
/* Footer */
/* ==================== */

.site-footer {
    background-color: var(--footer-bg);
    color: var(--footer-text);
    padding: var(--spacing-xl) 0 var(--spacing-md);
    margin-top: var(--spacing-xl);
}

.footer-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-lg);
}

.footer-section h3 {
    color: #ffffff;
    margin-top: 0;
}

.footer-section ul {
    list-style: none;
    padding: 0;
}

.footer-section li {
    margin: var(--spacing-xs) 0;
}

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

.footer-section a:hover {
    color: #ffffff;
}

.footer-bottom {
    max-width: 1200px;
    margin: var(--spacing-lg) auto 0;
    padding: var(--spacing-md) var(--spacing-md) 0;
    border-top: 1px solid #404040;
    text-align: center;
    color: var(--text-muted);
}

/* ==================== */
/* Responsive Design */
/* ==================== */

@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        left: -100%;
        top: 70px;
        flex-direction: column;
        background-color: var(--header-bg);
        width: 100%;
        text-align: center;
        transition: left 0.3s ease;
        box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
        padding: var(--spacing-md) 0;
        border-top: 1px solid var(--border-color);
    }

    .nav-menu.active {
        left: 0;
    }

    .nav-toggle {
        display: flex;
    }

    .lang-btn {
        padding: 0.2rem 0.4rem;
        font-size: 0.72rem;
    }

    .hero h1 {
        font-size: 2rem;
    }

    .hero .tagline {
        font-size: 1.1rem;
    }

    h1 { font-size: 2rem; }
    h2 { font-size: 1.6rem; }
    h3 { font-size: 1.3rem; }

    .container {
        padding: var(--spacing-md) var(--spacing-sm);
    }

    .projects-grid,
    .skills-grid,
    .kb-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    .hero h1 {
        font-size: 1.6rem;
    }

    .article-content ul,
    .article-content ol {
        margin-left: var(--spacing-md);
    }

    .contact-links {
        flex-direction: column;
    }
}

/* ==================== */
/* Utilities */
/* ==================== */

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

.mt-lg {
    margin-top: var(--spacing-lg);
}

.mb-lg {
    margin-bottom: var(--spacing-lg);
}

/* Print Styles */
@media print {
    .site-header,
    .site-footer,
    .theme-toggle,
    .nav-toggle {
        display: none;
    }

    body {
        background: white;
        color: black;
    }
}