/* ============================================
   Developer-Oriented Color Scheme
   Inspired by VS Code Dark Theme
   ============================================ */

:root {
    /* Background Colors */
    --bg-primary: #1e1e1e;
    --bg-secondary: #252526;
    --bg-tertiary: #2d2d30;
    --bg-hover: #2a2d2e;
    
    /* Text Colors */
    --text-primary: #d4d4d4;
    --text-secondary: #858585;
    --text-muted: #6a6a6a;
    
    /* Code Colors */
    --code-keyword: #569cd6;
    --code-function: #dcdcaa;
    --code-string: #ce9178;
    --code-comment: #6a9955;
    --code-variable: #9cdcfe;
    --code-number: #b5cea8;
    --code-operator: #d4d4d4;
    --code-bracket: #ffd700;
    
    /* Accent Colors */
    --accent-primary: #007acc;
    --accent-secondary: #4ec9b0;
    --accent-hover: #0098ff;
    
    /* Border Colors */
    --border-color: #3e3e42;
    --border-hover: #505050;
    
    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    
    /* Typography - GitHub-style fonts */
    --font-mono: 'SFMono-Regular', Consolas, 'Liberation Mono', Menlo, 'Courier New', monospace;
    --font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif;
}

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

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-sans);
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    font-feature-settings: "liga" 1, "calt" 1;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

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

h1, h2, h3, h4, h5, h6 {
    font-weight: 600;
    line-height: 1.2;
    margin-bottom: var(--spacing-sm);
}

h1 { font-size: 2.5rem; }
h2 { font-size: 2rem; }
h3 { font-size: 1.75rem; }
h4 { font-size: 1.5rem; }
h5 { font-size: 1.25rem; }
h6 { font-size: 1rem; }

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

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

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

/* ============================================
   Header
   ============================================ */

.header {
    background-color: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    padding: var(--spacing-md) 0;
    position: sticky;
    top: 0;
    z-index: 100;
    backdrop-filter: blur(10px);
}

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

.logo {
    font-family: var(--font-mono);
    font-size: 1.5rem;
    font-weight: 600;
    letter-spacing: -0.025em;
}

.logo-link {
    color: inherit;
}

.logo-link:hover {
    color: inherit;
}

.logo-bracket {
    color: var(--code-bracket);
}

.logo-text {
    color: var(--code-function);
}

.nav {
    display: flex;
    gap: var(--spacing-lg);
}

.nav-link {
    color: var(--text-secondary);
    font-weight: 500;
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: 4px;
    transition: all 0.2s ease;
}

.nav-link:hover {
    color: var(--text-primary);
    background-color: var(--bg-hover);
}

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

.hero {
    padding: var(--spacing-xl) 0;
    text-align: center;
    border-bottom: 1px solid var(--border-color);
}

.hero-title {
    margin-bottom: var(--spacing-md);
}

.code-comment {
    color: var(--code-comment);
    font-family: var(--font-mono);
    font-size: 1.2rem;
    font-weight: 400;
    letter-spacing: 0;
    display: block;
    margin-bottom: var(--spacing-sm);
}

.hero-main {
    font-size: 3rem;
    font-weight: 700;
    color: var(--text-primary);
    display: block;
}

.hero-description {
    font-size: 1.2rem;
    color: var(--text-secondary);
    max-width: 800px;
    margin: 0 auto;
}

/* ============================================
   Projects Section
   ============================================ */

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

.section-title {
    font-family: var(--font-mono);
    font-size: 1.5rem;
    font-weight: 600;
    letter-spacing: -0.025em;
    margin-bottom: var(--spacing-lg);
    color: var(--text-primary);
}

.code-keyword { color: var(--code-keyword); }
.code-variable { color: var(--code-variable); }
.code-function { color: var(--code-function); }
.code-operator { color: var(--code-operator); }
.code-bracket { color: var(--code-bracket); }

.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
}

.project-card {
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: var(--spacing-lg);
    transition: all 0.3s ease;
    cursor: pointer;
    display: flex;
    flex-direction: column;
}

.project-card:hover {
    border-color: var(--border-hover);
    background-color: var(--bg-tertiary);
    transform: translateY(-4px);
    box-shadow: 0 8px 16px rgba(0, 0, 0, 0.3);
}

.project-card-header {
    margin-bottom: var(--spacing-sm);
}

.project-card-category {
    display: inline-block;
    background-color: var(--bg-tertiary);
    color: var(--code-keyword);
    font-family: var(--font-mono);
    font-size: 0.8125rem;
    font-weight: 400;
    letter-spacing: 0;
    padding: 0.25rem 0.75rem;
    border-radius: 4px;
    margin-bottom: var(--spacing-xs);
}

.project-card-title {
    font-size: 1.5rem;
    color: var(--code-function);
    margin-bottom: var(--spacing-xs);
}

.project-card-description {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-sm);
    flex-grow: 1;
}

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

.project-tag {
    background-color: var(--bg-tertiary);
    color: var(--code-string);
    font-family: var(--font-mono);
    font-size: 0.75rem;
    font-weight: 400;
    letter-spacing: 0;
    padding: 0.2rem 0.6rem;
    border-radius: 4px;
    border: 1px solid var(--border-color);
}

.section-closer {
    font-family: var(--font-mono);
    font-size: 1.5rem;
    font-weight: 400;
    letter-spacing: 0;
    color: var(--code-bracket);
    margin-top: var(--spacing-lg);
}

/* ============================================
   About Section
   ============================================ */

.about-section {
    padding: var(--spacing-xl) 0;
    border-top: 1px solid var(--border-color);
}

.about-content {
    max-width: 800px;
    margin: var(--spacing-lg) 0;
}

.about-content p {
    color: var(--text-secondary);
    font-size: 1.1rem;
    margin-bottom: var(--spacing-md);
}

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

.project-article {
    padding: var(--spacing-xl) 0;
}

.project-header {
    margin-bottom: var(--spacing-xl);
    padding-bottom: var(--spacing-lg);
    border-bottom: 1px solid var(--border-color);
}

.project-meta {
    display: flex;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-md);
    flex-wrap: wrap;
}

.project-category {
    background-color: var(--bg-tertiary);
    color: var(--code-keyword);
    font-family: var(--font-mono);
    font-size: 0.8125rem;
    font-weight: 400;
    letter-spacing: 0;
    padding: 0.4rem 0.8rem;
    border-radius: 4px;
}

.project-date {
    color: var(--text-muted);
    font-family: var(--font-mono);
    font-size: 0.875rem;
    font-weight: 400;
    letter-spacing: 0;
}

.project-title {
    font-size: 3rem;
    color: var(--code-function);
    margin-bottom: var(--spacing-md);
}

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

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

.project-content {
    max-width: 900px;
    margin: var(--spacing-xl) auto;
    line-height: 1.8;
}

.project-content h2 {
    color: var(--code-function);
    margin-top: var(--spacing-xl);
    margin-bottom: var(--spacing-md);
    padding-bottom: var(--spacing-xs);
    border-bottom: 1px solid var(--border-color);
}

.project-content h3 {
    color: var(--code-variable);
    margin-top: var(--spacing-lg);
    margin-bottom: var(--spacing-sm);
}

.project-content p {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-md);
    font-size: 1.05rem;
}

.project-content ul,
.project-content ol {
    margin-left: var(--spacing-lg);
    margin-bottom: var(--spacing-md);
    color: var(--text-secondary);
}

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

.project-content code {
    background-color: var(--bg-secondary);
    color: var(--code-string);
    font-family: var(--font-mono);
    font-size: 0.85em;
    font-weight: 400;
    padding: 0.2rem 0.4rem;
    border-radius: 4px;
    border: 1px solid var(--border-color);
    letter-spacing: 0;
}

.project-content pre {
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: var(--spacing-md);
    overflow-x: auto;
    margin: var(--spacing-md) 0;
    font-family: var(--font-mono);
    font-size: 0.875rem;
    line-height: 1.6;
}

.project-content pre code {
    background: none;
    border: none;
    padding: 0;
    color: var(--text-primary);
    font-size: inherit;
    font-family: inherit;
    line-height: inherit;
    letter-spacing: 0;
    font-weight: 400;
}

.project-content blockquote {
    border-left: 4px solid var(--accent-primary);
    padding-left: var(--spacing-md);
    margin: var(--spacing-md) 0;
    color: var(--text-secondary);
    font-style: italic;
}

.project-content a {
    color: var(--accent-primary);
    text-decoration: underline;
}

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

.project-footer {
    margin-top: var(--spacing-xl);
    padding-top: var(--spacing-lg);
    border-top: 1px solid var(--border-color);
}

.project-links {
    margin-bottom: var(--spacing-md);
}

.project-link {
    display: inline-block;
    background-color: var(--bg-secondary);
    color: var(--accent-primary);
    padding: var(--spacing-xs) var(--spacing-md);
    border-radius: 4px;
    border: 1px solid var(--border-color);
    margin-right: var(--spacing-sm);
    margin-bottom: var(--spacing-xs);
    transition: all 0.2s ease;
}

.project-link:hover {
    background-color: var(--bg-tertiary);
    border-color: var(--accent-primary);
}

.back-link {
    display: inline-block;
    color: var(--text-secondary);
    font-family: var(--font-mono);
    font-weight: 400;
    letter-spacing: 0;
    margin-top: var(--spacing-md);
}

.back-link:hover {
    color: var(--accent-primary);
}

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

.footer {
    background-color: var(--bg-secondary);
    border-top: 1px solid var(--border-color);
    padding: var(--spacing-lg) 0;
    text-align: center;
    margin-top: var(--spacing-xl);
}

.footer-text {
    font-family: var(--font-mono);
    font-weight: 400;
    letter-spacing: 0;
    color: var(--text-muted);
    margin-bottom: var(--spacing-xs);
}

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

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

@media (max-width: 768px) {
    .hero-main {
        font-size: 2rem;
    }
    
    .projects-grid {
        grid-template-columns: 1fr;
    }
    
    .project-title {
        font-size: 2rem;
    }
    
    .header .container {
        flex-direction: column;
        gap: var(--spacing-md);
    }
    
    .nav {
        flex-direction: column;
        gap: var(--spacing-sm);
        width: 100%;
    }
    
    .nav-link {
        text-align: center;
    }
}

/* ============================================
   Projects Showcase Page
   ============================================ */

.showcase-hero {
    padding: var(--spacing-xl) 0;
    text-align: center;
    border-bottom: 1px solid var(--border-color);
}

.showcase-title {
    font-family: var(--font-mono);
    font-size: 2rem;
    font-weight: 600;
    letter-spacing: -0.025em;
    margin-bottom: var(--spacing-md);
}

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

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

.showcase-filters {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-lg);
    justify-content: center;
}

.filter-btn {
    background-color: var(--bg-secondary);
    color: var(--text-secondary);
    font-family: var(--font-mono);
    font-size: 0.875rem;
    font-weight: 400;
    letter-spacing: 0;
    padding: 0.5rem 1rem;
    border: 1px solid var(--border-color);
    border-radius: 6px;
    cursor: pointer;
    transition: all 0.2s ease;
}

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

.filter-btn.active {
    background-color: var(--accent-primary);
    border-color: var(--accent-primary);
    color: var(--text-primary);
    font-weight: 500;
}

.showcase-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
}

.showcase-card {
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: var(--spacing-lg);
    transition: all 0.3s ease;
    cursor: pointer;
    display: flex;
    flex-direction: column;
    opacity: 1;
    transform: translateY(0);
}

.showcase-card:hover {
    border-color: var(--border-hover);
    background-color: var(--bg-tertiary);
    transform: translateY(-4px);
    box-shadow: 0 8px 16px rgba(0, 0, 0, 0.3);
}

.showcase-card-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-sm);
    flex-wrap: wrap;
    gap: var(--spacing-xs);
}

.showcase-card-category {
    background-color: var(--bg-tertiary);
    color: var(--code-keyword);
    font-family: var(--font-mono);
    font-size: 0.8125rem;
    font-weight: 400;
    letter-spacing: 0;
    padding: 0.25rem 0.75rem;
    border-radius: 4px;
}

.showcase-card-date {
    color: var(--text-muted);
    font-family: var(--font-mono);
    font-size: 0.8125rem;
    font-weight: 400;
    letter-spacing: 0;
}

.showcase-card-title {
    font-size: 1.5rem;
    color: var(--code-function);
    margin-bottom: var(--spacing-sm);
    font-weight: 600;
}

.showcase-card-description {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-md);
    flex-grow: 1;
    line-height: 1.6;
}

.showcase-card-tags {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-xs);
    margin-bottom: var(--spacing-md);
}

.showcase-card-footer {
    margin-top: auto;
    padding-top: var(--spacing-sm);
    border-top: 1px solid var(--border-color);
}

.showcase-card-link {
    color: var(--accent-primary);
    font-family: var(--font-mono);
    font-size: 0.875rem;
    font-weight: 500;
    letter-spacing: 0;
    transition: color 0.2s ease;
}

.showcase-card:hover .showcase-card-link {
    color: var(--accent-hover);
}

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

/* ============================================
   Feature Timeline
   ============================================ */

.feature-timeline {
    margin: var(--spacing-xl) 0;
    position: relative;
    padding-left: var(--spacing-lg);
}

.feature-timeline::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 2px;
    background: var(--border-color);
}

.timeline-item {
    position: relative;
    margin-bottom: var(--spacing-xl);
    padding-left: var(--spacing-lg);
}

.timeline-item::before {
    content: '';
    position: absolute;
    left: -6px;
    top: 0.5rem;
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background: var(--accent-primary);
    border: 2px solid var(--bg-primary);
    z-index: 1;
}

.timeline-date {
    font-family: var(--font-mono);
    font-size: 0.875rem;
    color: var(--code-keyword);
    font-weight: 500;
    margin-bottom: var(--spacing-xs);
}

.timeline-content h4 {
    color: var(--code-function);
    font-size: 1.25rem;
    margin-bottom: var(--spacing-sm);
    font-weight: 600;
}

.timeline-content p {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-sm);
    line-height: 1.7;
}

.timeline-content ul {
    margin-left: var(--spacing-md);
    margin-top: var(--spacing-xs);
}

.timeline-content li {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-xs);
    font-size: 0.95rem;
}

/* ============================================
   Commit History (GitHub-style)
   ============================================ */

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

.commit-item {
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: var(--spacing-md);
    margin-bottom: var(--spacing-md);
    transition: all 0.2s ease;
}

.commit-item:hover {
    border-color: var(--border-hover);
    background-color: var(--bg-tertiary);
}

.commit-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-xs);
    flex-wrap: wrap;
    gap: var(--spacing-xs);
}

.commit-hash {
    font-family: var(--font-mono);
    font-size: 0.875rem;
    color: var(--code-keyword);
    font-weight: 500;
    background-color: var(--bg-tertiary);
    padding: 0.2rem 0.5rem;
    border-radius: 4px;
    border: 1px solid var(--border-color);
}

.commit-date {
    font-family: var(--font-mono);
    font-size: 0.8125rem;
    color: var(--text-muted);
}

.commit-message {
    font-family: var(--font-mono);
    font-size: 1rem;
    color: var(--text-primary);
    font-weight: 500;
    margin-bottom: var(--spacing-sm);
}

.commit-body {
    margin-top: var(--spacing-sm);
}

.commit-body p {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-sm);
    line-height: 1.6;
    font-size: 0.95rem;
}

.commit-stats {
    display: flex;
    gap: var(--spacing-md);
    margin-top: var(--spacing-sm);
    padding-top: var(--spacing-sm);
    border-top: 1px solid var(--border-color);
    flex-wrap: wrap;
}

.commit-stats .stat {
    font-family: var(--font-mono);
    font-size: 0.8125rem;
    color: var(--text-muted);
}

.commit-stats .stat:first-child {
    color: var(--code-comment);
}

.commit-stats .stat:nth-child(2) {
    color: var(--code-string);
}

@media (max-width: 768px) {
    .showcase-grid {
        grid-template-columns: 1fr;
    }
    
    .showcase-title {
        font-size: 1.5rem;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 var(--spacing-sm);
    }
    
    .hero {
        padding: var(--spacing-lg) 0;
    }
    
    .hero-main {
        font-size: 1.5rem;
    }
    
    .code-comment {
        font-size: 1rem;
    }
    
    .showcase-filters {
        justify-content: flex-start;
    }
    
    .feature-timeline {
        padding-left: var(--spacing-md);
    }
    
    .timeline-item {
        padding-left: var(--spacing-md);
    }
    
    .commit-header {
        flex-direction: column;
        align-items: flex-start;
    }
}