/* ===================================
   CSS Variables for Theme Support
   =================================== */
:root {
    /* Light mode colors */
    --color-bg: #ffffff;
    --color-text: #1a1a1a;
    --color-text-light: #666666;
    --color-border: #e0e0e0;
    --color-accent: #4a4a4a;
    --color-accent-hover: #2a2a2a;
    --color-header-bg: #ffffff;
    --color-toc-bg: #fafafa;
    --color-code-bg: #f5f5f5;
    --color-badge-bg: #e8e8e8;
    --color-badge-text: #4a4a4a;

    /* Typography */
    --font-serif: 'Crimson Pro', Georgia, serif;
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;

    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --spacing-2xl: 4rem;

    /* Layout */
    --max-content-width: 1200px;
    --content-width: 720px;
    --toc-width: 240px;
}

/* Dark mode colors */
[data-theme="dark"] {
    --color-bg: #1a1a1a;
    --color-text: #e8e8e8;
    --color-text-light: #a0a0a0;
    --color-border: #333333;
    --color-accent: #b0b0b0;
    --color-accent-hover: #d0d0d0;
    --color-header-bg: #111111;
    --color-toc-bg: #242424;
    --color-code-bg: #2a2a2a;
    --color-badge-bg: #333333;
    --color-badge-text: #b0b0b0;
}

/* ===================================
   Global Styles
   =================================== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: var(--font-serif);
    font-size: 1.25rem;
    line-height: 1.8;
    color: var(--color-text);
    background-color: var(--color-bg);
    transition: background-color 0.3s ease, color 0.3s ease;
}

/* ===================================
   Typography
   =================================== */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-sans);
    font-weight: 600;
    line-height: 1.3;
    margin-bottom: var(--spacing-md);
}

h1 {
    font-size: 2.5rem;
    margin-bottom: var(--spacing-lg);
}

h2 {
    font-size: 2rem;
    margin-top: var(--spacing-2xl);
    margin-bottom: var(--spacing-lg);
}

h3 {
    font-size: 1.5rem;
    margin-top: var(--spacing-xl);
}

h4 {
    font-size: 1.25rem;
    margin-top: var(--spacing-lg);
}

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

.lead {
    font-size: 1.375rem;
    line-height: 1.7;
    color: var(--color-text);
    margin-bottom: var(--spacing-lg);
}

#about p {
    font-size: 1.375rem;
    line-height: 1.7;
}

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

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

ul, ol {
    margin-bottom: var(--spacing-md);
    padding-left: var(--spacing-lg);
}

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

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

/* ===================================
   Container & Layout
   =================================== */
.container {
    max-width: var(--max-content-width);
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
}

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

.site-header .container {
    display: flex;
    justify-content: center;
    align-items: center;
    position: relative;
}

.site-title {
    font-family: 'Niconne', cursive;
    font-size: 2.5rem;
    font-weight: 400;
    margin: 0;
    text-align: center;
}

.site-nav {
    position: absolute;
    right: var(--spacing-lg);
    display: flex;
    align-items: center;
}

/* Theme Toggle Button */
.theme-toggle {
    background: none;
    border: 1px solid var(--color-border);
    border-radius: 6px;
    padding: 0.5rem 0.75rem;
    cursor: pointer;
    font-size: 1.25rem;
    color: var(--color-text);
    transition: all 0.2s ease;
}

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

/* ===================================
   Main Content Layout
   =================================== */
.site-main {
    padding: var(--spacing-2xl) 0;
    min-height: calc(100vh - 200px);
}

.content-wrapper {
    display: grid;
    grid-template-columns: var(--toc-width) 1fr;
    gap: var(--spacing-2xl);
    align-items: start;
}

/* ===================================
   Table of Contents
   =================================== */
.table-of-contents {
    position: sticky;
    top: 120px;
    background-color: var(--color-toc-bg);
    border-radius: 8px;
    padding: var(--spacing-lg);
}

.toc-title {
    font-size: 0.75rem;
    font-weight: 600;
    margin-bottom: var(--spacing-md);
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--color-text-light);
}

.toc-list {
    list-style: none;
    padding: 0;
    margin: 0;
    margin-top: 0;
}

.toc-list li {
    margin-bottom: 0;
}

.toc-list a {
    color: var(--color-text);
    font-family: var(--font-serif);
    font-size: 1rem;
    display: block;
    padding: 0.5rem 0.75rem;
    transition: all 0.2s ease;
    border-radius: 6px;
}

.toc-list a:hover {
    color: var(--color-accent);
    background-color: var(--color-bg);
}

.toc-list > li > a {
    font-weight: 500;
}

.toc-list ul {
    list-style: none;
    margin-top: 0;
    margin-bottom: 0;
    padding-left: var(--spacing-md);
}

.toc-list ul li {
    margin-bottom: 0;
}

.toc-list ul a {
    font-size: 0.85rem;
    color: var(--color-text-light);
    padding: 0.4rem 0.75rem;
    font-weight: 400;
}

/* ===================================
   Social Links (Sidebar)
   =================================== */
.social-links {
    display: flex;
    gap: var(--spacing-sm);
    margin-top: var(--spacing-lg);
    padding-top: var(--spacing-lg);
    border-top: 1px solid var(--color-border);
    justify-content: center;
}

.social-link {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background-color: var(--color-bg);
    border: 1px solid var(--color-border);
    color: var(--color-text);
    transition: all 0.3s ease;
}

.social-link:hover {
    background-color: var(--color-accent);
    border-color: var(--color-accent);
    color: #ffffff;
    transform: translateY(-2px);
}

.social-link svg {
    width: 20px;
    height: 20px;
}

/* ===================================
   Main Content
   =================================== */
.main-content {
    max-width: var(--content-width);
}

.content-section {
    margin-bottom: var(--spacing-2xl);
}

.section-title {
    border-bottom: 1px solid var(--color-border);
    padding-bottom: var(--spacing-sm);
}

/* ===================================
   Project Items
   =================================== */
.project-item {
    margin-bottom: var(--spacing-2xl);
    padding-bottom: var(--spacing-2xl);
    border-bottom: 1px solid var(--color-border);
}

.project-item:last-child {
    border-bottom: none;
}

.project-title {
    font-size: 1.75rem;
    margin-bottom: var(--spacing-xs);
}

.project-meta {
    font-family: var(--font-sans);
    font-size: 0.9rem;
    color: var(--color-text-light);
    margin-bottom: var(--spacing-lg);
}

.tech-stack {
    font-family: var(--font-sans);
    font-size: 0.9rem;
    color: var(--color-text-light);
    padding: var(--spacing-md);
    background-color: var(--color-code-bg);
    border-radius: 6px;
    border-left: 2px solid var(--color-accent);
}

.project-link,
.project-links {
    margin-top: var(--spacing-md);
}

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

/* ===================================
   Hobby Items
   =================================== */
.hobby-item {
    margin-bottom: var(--spacing-xl);
}

.hobby-title {
    font-size: 1.5rem;
    margin-bottom: var(--spacing-xs);
}

.hobby-meta {
    font-family: var(--font-sans);
    font-size: 0.9rem;
    color: var(--color-text-light);
    margin-bottom: var(--spacing-lg);
}

/* ===================================
   Open Source Grid
   =================================== */
.opensource-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--spacing-xl);
    margin-top: var(--spacing-lg);
}

.opensource-item {
    padding: var(--spacing-lg);
    background-color: var(--color-toc-bg);
    border-radius: 8px;
    border: 1px solid var(--color-border);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.opensource-item:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

.opensource-title {
    font-size: 1.25rem;
    margin-bottom: var(--spacing-sm);
}

.opensource-meta {
    margin-bottom: var(--spacing-md);
}

.badge {
    display: inline-block;
    font-family: var(--font-sans);
    font-size: 0.75rem;
    padding: 0.25rem 0.75rem;
    background-color: var(--color-badge-bg);
    color: var(--color-badge-text);
    border-radius: 12px;
    margin-right: var(--spacing-xs);
    font-weight: 500;
}

.opensource-links {
    margin-top: var(--spacing-md);
}

.opensource-links a {
    margin-right: var(--spacing-md);
}

/* ===================================
   Writing Section
   =================================== */
.writing-list {
    margin-top: var(--spacing-lg);
}

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

.writing-item:last-child {
    border-bottom: none;
}

.writing-title {
    font-size: 1.25rem;
    margin-bottom: var(--spacing-xs);
}

.writing-meta {
    font-family: var(--font-sans);
    font-size: 0.9rem;
    color: var(--color-text-light);
    margin-bottom: var(--spacing-sm);
}

.more-writing {
    margin-top: var(--spacing-lg);
    text-align: center;
}

/* ===================================
   Skills Grid
   =================================== */
.skills-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--spacing-lg);
    margin-top: var(--spacing-lg);
}

.skill-category h3 {
    font-size: 1.125rem;
    margin-top: 0;
    margin-bottom: var(--spacing-sm);
    color: var(--color-accent);
}

.skill-category p {
    font-family: var(--font-sans);
    font-size: 0.95rem;
    line-height: 1.7;
    margin-bottom: 0;
}

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

.certifications h3 {
    font-size: 1.25rem;
    margin-bottom: var(--spacing-md);
}

.certifications ul {
    font-family: var(--font-sans);
    font-size: 0.95rem;
}

/* ===================================
   Contact Section
   =================================== */
.contact-links {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
    margin: var(--spacing-lg) 0;
}

.contact-link {
    font-family: var(--font-sans);
    font-size: 1.125rem;
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-md);
    background-color: var(--color-toc-bg);
    border-radius: 6px;
    border: 1px solid var(--color-border);
    transition: all 0.2s ease;
}

.contact-link:hover {
    background-color: var(--color-bg);
    border-color: var(--color-accent);
    transform: translateX(4px);
}

.contact-icon {
    font-size: 1.5rem;
}

.location {
    font-family: var(--font-sans);
    font-size: 0.95rem;
    color: var(--color-text-light);
    margin-top: var(--spacing-lg);
}

/* ===================================
   Footer
   =================================== */
.site-footer {
    border-top: 1px solid var(--color-border);
    padding: var(--spacing-xl) 0;
    text-align: center;
}

.site-footer p {
    font-family: var(--font-sans);
    font-size: 0.9rem;
    color: var(--color-text-light);
    margin: 0;
}

/* ===================================
   Responsive Design
   =================================== */
@media (max-width: 968px) {
    .content-wrapper {
        grid-template-columns: 1fr;
        gap: var(--spacing-lg);
    }

    .table-of-contents {
        position: static;
        margin-bottom: var(--spacing-lg);
    }
}

@media (max-width: 768px) {
    html {
        font-size: 15px;
    }

    .container {
        padding: 0 var(--spacing-md);
    }

    h1 {
        font-size: 2rem;
    }

    h2 {
        font-size: 1.75rem;
        margin-top: var(--spacing-xl);
    }

    h3 {
        font-size: 1.375rem;
    }

    .lead {
        font-size: 1.25rem;
    }

    .site-header {
        padding: var(--spacing-md) 0;
    }

    .site-title {
        font-size: 3rem;
    }

    .site-main {
        padding: var(--spacing-lg) 0;
    }

    .toc-list a {
        font-size: 1.25rem;
        padding: 0.4rem 1rem;
    }

    .opensource-grid {
        gap: var(--spacing-lg);
    }

    .contact-links {
        gap: var(--spacing-sm);
    }
}

@media (max-width: 480px) {
    html {
        font-size: 14px;
    }

    .container {
        padding: 0 var(--spacing-sm);
    }

    .site-title {
        font-size: 2.5rem;
    }

    .site-nav {
        right: var(--spacing-sm);
    }

    .toc-list a {
        font-size: 1.25rem;
        padding: 0.4rem 1rem;
    }

    .project-links a,
    .opensource-links a {
        display: block;
        margin: var(--spacing-xs) 0;
    }
}

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

    body {
        font-size: 12pt;
        color: #000;
        background: #fff;
    }

    .content-wrapper {
        grid-template-columns: 1fr;
    }

    a {
        color: #000;
        text-decoration: underline;
    }

    .project-item,
    .writing-item {
        page-break-inside: avoid;
    }
}