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

:root {
    --bg-page: #ffffff;
    --bg-subtle: #f7f7fa;
    --bg-nav: #1a1a2e;
    --text-primary: rgba(0, 0, 0, 0.90);
    --text-secondary: rgba(0, 0, 0, 0.65);
    --text-muted: rgba(0, 0, 0, 0.45);
    --text-light: #ffffff;
    --accent: #7297c5;
    --accent-dark: #5a7fb0;
    --accent-subtle: rgba(114, 151, 197, 0.12);
    --border: #dcdce0;
    --border-light: #e8e8ec;
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.06);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.10);
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    background-color: var(--bg-page);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
}

/* Navigation */
.nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: var(--bg-nav);
    border-bottom: none;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 40px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 64px;
}

.nav-logo {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--text-light);
    text-decoration: none;
    letter-spacing: -0.01em;
}

.nav-logo span {
    color: var(--accent);
}

.nav-links {
    display: flex;
    gap: 4px;
}

.nav-link {
    color: rgba(255, 255, 255, 0.75);
    text-decoration: none;
    font-size: 0.875rem;
    font-weight: 500;
    padding: 8px 16px;
    border-radius: 4px;
    transition: all 0.2s ease;
}

.nav-link:hover,
.nav-link.active {
    color: var(--text-light);
    background: rgba(255, 255, 255, 0.1);
}

/* Container */
.container {
    max-width: 1000px;
    margin: 0 auto;
    padding: 104px 40px 80px;
}

/* Hero Section */
.hero {
    text-align: center;
    padding: 80px 0 64px;
    border-bottom: 1px solid var(--border);
    margin-bottom: 64px;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 700;
    letter-spacing: -0.03em;
    margin-bottom: 16px;
    color: var(--text-primary);
}

.hero-subtitle {
    font-size: 1.25rem;
    color: var(--text-secondary);
    font-weight: 400;
    margin-bottom: 8px;
}

.hero-tagline {
    font-size: 0.875rem;
    color: var(--text-muted);
    font-weight: 500;
    letter-spacing: 0.08em;
    text-transform: uppercase;
}

/* Social Links */
.social-links {
    display: flex;
    justify-content: center;
    gap: 12px;
    margin-top: 32px;
}

.social-btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 10px 20px;
    background: var(--bg-page);
    color: var(--text-primary);
    text-decoration: none;
    border-radius: 24px;
    font-size: 0.875rem;
    font-weight: 500;
    border: 1px solid var(--border);
    transition: all 0.2s ease;
}

.social-btn:hover {
    background: var(--bg-subtle);
    border-color: var(--accent);
    color: var(--accent-dark);
}

.social-btn svg {
    flex-shrink: 0;
}

/* About Section */
.about {
    padding: 32px;
    background: var(--bg-subtle);
    border-radius: 8px;
    margin-bottom: 64px;
    border-left: 3px solid var(--accent);
}

.about-text {
    font-size: 1.0625rem;
    color: var(--text-secondary);
    line-height: 1.8;
}

.about-text strong {
    color: var(--text-primary);
    font-weight: 600;
}

/* Section Styles */
section {
    margin-bottom: 64px;
}

.section-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 28px;
}

.section-title {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-primary);
    position: relative;
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: -8px;
    left: 0;
    width: 32px;
    height: 2px;
    background: var(--accent);
}

.section-link {
    color: var(--accent);
    text-decoration: none;
    font-size: 0.875rem;
    font-weight: 500;
    transition: color 0.2s;
}

.section-link:hover {
    color: var(--accent-dark);
    text-decoration: underline;
}

/* Education */
.edu-grid {
    display: grid;
    gap: 12px;
}

.edu-item {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    padding: 20px 24px;
    background: var(--bg-page);
    border-radius: 8px;
    border: 1px solid var(--border);
    transition: all 0.2s ease;
}

.edu-item:hover {
    border-color: var(--accent);
    box-shadow: var(--shadow-sm);
}

.edu-info h3 {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 4px;
}

.edu-info p {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.edu-date {
    font-size: 0.8125rem;
    color: var(--accent);
    font-weight: 500;
    white-space: nowrap;
}

/* Experience */
.exp-grid {
    display: grid;
    gap: 16px;
}

.exp-item {
    padding: 24px;
    background: var(--bg-page);
    border-radius: 8px;
    border: 1px solid var(--border);
    transition: all 0.2s ease;
}

.exp-item:hover {
    border-color: var(--accent);
    box-shadow: var(--shadow-sm);
}

.exp-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 16px;
    flex-wrap: wrap;
    gap: 8px;
}

.exp-title h3 {
    font-size: 1.0625rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 2px;
}

.exp-title p {
    font-size: 0.875rem;
    color: var(--accent);
    font-weight: 500;
}

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

.exp-desc {
    font-size: 0.9375rem;
    color: var(--text-secondary);
    line-height: 1.7;
}

.exp-desc ul {
    padding-left: 18px;
}

.exp-desc li {
    margin-bottom: 6px;
}

.exp-desc li::marker {
    color: var(--accent);
}

/* Projects Grid */
.project-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 16px;
}

.project-card {
    background: var(--bg-page);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 24px;
    transition: all 0.2s ease;
}

.project-card:hover {
    border-color: var(--accent);
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
}

.project-name {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 8px;
    color: var(--text-primary);
}

.project-desc {
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin-bottom: 16px;
    line-height: 1.6;
}

.project-tags {
    display: flex;
    gap: 6px;
    flex-wrap: wrap;
}

.tag {
    font-size: 0.6875rem;
    padding: 4px 10px;
    background: var(--accent-subtle);
    color: var(--accent-dark);
    border-radius: 4px;
    font-weight: 500;
}

/* Skills */
.skills-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 16px;
}

.skill-category {
    padding: 20px;
    background: var(--bg-subtle);
    border-radius: 8px;
}

.skill-category h3 {
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--accent-dark);
    margin-bottom: 12px;
    text-transform: uppercase;
    letter-spacing: 0.06em;
}

.skill-list {
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.skill-item {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

/* Posts Section (Homepage Preview) */
.posts-preview {
    margin-bottom: 64px;
}

.post-list {
    display: grid;
    gap: 12px;
}

.post-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 24px;
    background: var(--bg-page);
    border-radius: 8px;
    border: 1px solid var(--border);
    text-decoration: none;
    transition: all 0.2s ease;
}

.post-item:hover {
    border-color: var(--accent);
    box-shadow: var(--shadow-sm);
}

.post-info h3 {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 4px;
}

.post-info p {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.post-meta {
    display: flex;
    align-items: center;
    gap: 16px;
}

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

.post-arrow {
    color: var(--accent);
    font-size: 1.125rem;
}

/* Footer */
.footer {
    text-align: center;
    padding: 32px 0;
    border-top: 1px solid var(--border);
    color: var(--text-muted);
    font-size: 0.8125rem;
}

/* Posts Page Styles */
.page-header {
    padding: 48px 0 32px;
    border-bottom: 1px solid var(--border);
    margin-bottom: 40px;
}

.page-title {
    font-size: 2.25rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 8px;
}

.page-desc {
    font-size: 1rem;
    color: var(--text-secondary);
}

.posts-grid {
    display: grid;
    gap: 16px;
}

.post-card {
    padding: 28px;
    background: var(--bg-page);
    border-radius: 8px;
    border: 1px solid var(--border);
    text-decoration: none;
    transition: all 0.2s ease;
}

.post-card:hover {
    border-color: var(--accent);
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
}

.post-card-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 12px;
}

.post-card h2 {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--text-primary);
    line-height: 1.4;
}

.post-card-date {
    font-size: 0.8125rem;
    color: var(--text-muted);
    white-space: nowrap;
}

.post-card-excerpt {
    font-size: 0.9375rem;
    color: var(--text-secondary);
    line-height: 1.7;
    margin-bottom: 16px;
}

.post-card-tags {
    display: flex;
    gap: 6px;
    flex-wrap: wrap;
}

.post-tag {
    font-size: 0.6875rem;
    padding: 4px 10px;
    background: var(--accent-subtle);
    color: var(--accent-dark);
    border-radius: 4px;
    font-weight: 500;
}

/* Single Post Page */
.post-content {
    max-width: 680px;
    margin: 0 auto;
}

.post-header {
    margin-bottom: 40px;
    padding-bottom: 24px;
    border-bottom: 1px solid var(--border);
}

.post-header h1 {
    font-size: 2.25rem;
    font-weight: 700;
    color: var(--text-primary);
    line-height: 1.3;
    margin-bottom: 16px;
}

.post-header-meta {
    display: flex;
    gap: 20px;
    color: var(--text-muted);
    font-size: 0.875rem;
}

.post-body {
    font-size: 1.0625rem;
    line-height: 1.8;
    color: var(--text-secondary);
}

.post-body h2 {
    font-size: 1.375rem;
    font-weight: 600;
    color: var(--text-primary);
    margin: 40px 0 20px;
}

.post-body h3 {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--text-primary);
    margin: 32px 0 12px;
}

.post-body p {
    margin-bottom: 20px;
}

.post-body ul,
.post-body ol {
    margin-bottom: 20px;
    padding-left: 20px;
}

.post-body li {
    margin-bottom: 8px;
}

.post-body code {
    background: var(--bg-subtle);
    padding: 2px 6px;
    border-radius: 4px;
    font-size: 0.9em;
    color: var(--accent-dark);
}

.post-body pre {
    background: var(--bg-nav);
    color: var(--text-light);
    padding: 20px;
    border-radius: 8px;
    overflow-x: auto;
    margin-bottom: 20px;
}

.post-body pre code {
    background: none;
    padding: 0;
    color: inherit;
}

.post-body blockquote {
    border-left: 3px solid var(--accent);
    padding-left: 20px;
    margin: 28px 0;
    color: var(--text-muted);
    font-style: italic;
}

.post-body a {
    color: var(--accent);
    text-decoration: none;
}

.post-body a:hover {
    text-decoration: underline;
}

/* Back Link */
.back-link {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.875rem;
    margin-bottom: 24px;
    transition: color 0.2s;
}

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

/* Responsive */
@media (max-width: 900px) {
    .project-grid {
        grid-template-columns: 1fr;
    }

    .skills-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 640px) {
    .nav-container {
        padding: 0 20px;
    }

    .nav-links {
        gap: 0;
    }

    .nav-link {
        padding: 8px 12px;
        font-size: 0.8125rem;
    }

    .container {
        padding: 88px 20px 60px;
    }

    .hero {
        padding: 48px 0 40px;
    }

    .hero-title {
        font-size: 2.25rem;
    }

    .hero-subtitle {
        font-size: 1.125rem;
    }

    .social-links {
        flex-direction: column;
        align-items: center;
    }

    .social-btn {
        width: 100%;
        max-width: 180px;
        justify-content: center;
    }

    .edu-item {
        flex-direction: column;
        gap: 8px;
    }

    .exp-header {
        flex-direction: column;
    }

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

    .post-item {
        flex-direction: column;
        align-items: flex-start;
        gap: 8px;
    }

    .page-title {
        font-size: 1.75rem;
    }
}