:root {
    --text-primary: #1a1a1a;
    --text-secondary: #2d2d2d;
    --text-muted: #666;
    --accent-blue: #64b5f6;
    --accent-lavender: #ba68c8;
    --accent-mint: #4db6ac;
    --glass-bg: rgba(255, 255, 255, 0.7);
    --glass-border: rgba(255, 255, 255, 0.4);
    --border-light: rgba(0, 0, 0, 0.08);
    --spacing-xs: 8px;
    --spacing-sm: 16px;
    --spacing-md: 24px;
    --spacing-lg: 32px;
    --spacing-xl: 48px;
    --spacing-2xl: 64px;
    --spacing-3xl: 88px;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Inter', 'Segoe UI', 'Helvetica Neue', Arial, sans-serif;
    background: linear-gradient(135deg, #ffffff 0%, #f5f5f5 100%);
    color: var(--text-primary);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    min-height: 100vh;
}

/* Homepage Layout */
.container {
    display: flex;
    min-height: 100vh;
    max-width: 1400px;
    margin: 0 auto;
    padding-left: 40px;
    padding-right: 40px;
}

/* Left Sidebar */
.sidebar {
    width: 38%;
    position: sticky;
    top: 0;
    height: 100vh;
    padding: var(--spacing-2xl) 0;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.sidebar-content {
    max-width: 480px;
}

.sidebar h1 {
    font-size: 42px;
    font-weight: 600;
    letter-spacing: -0.01em;
    margin-bottom: var(--spacing-md);
    color: var(--text-primary);
    line-height: 1.1;
}

.sidebar .tagline {
    font-size: 20px;
    font-weight: 400;
    color: var(--text-muted);
    margin-bottom: var(--spacing-lg);
    line-height: 1.5;
}

.sidebar nav {
    display: flex;
    flex-direction: column;
    gap: 12px; /* Fixed: Reduced gap between About and Contact */
}

/* Navigation Toggle Buttons (Fixed: Minimal text-only style) */
.nav-toggle {
    background: none;
    border: none;
    color: var(--text-primary);
    text-decoration: none;
    font-size: 18px; /* Slightly larger for clear hierarchy */
    font-weight: 400;
    cursor: pointer;
    text-align: left;
    font-family: inherit;
    display: block;
    width: fit-content;
    padding: 0;
    transition: none;
}

/* Navigation Expandable Content */
.nav-content {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.1s ease-in-out;
    margin-top: 0;
}

.nav-content.active {
    max-height: 600px;
    margin-top: 0px; /* Fixed: Minimal gap between button and content */
    margin-bottom: var(--spacing-md);
}

.nav-content p {
    font-size: 16px;
    line-height: 1.6;
    color: var(--text-muted);
    margin: 0;
}

.sidebar .nav-content a {
    color: var(--text-muted);
    text-decoration: underline;
}

/* Right Column */
.main-content {
    width: 62%;
    padding: var(--spacing-2xl) var(--spacing-lg) var(--spacing-2xl) var(--spacing-3xl);
}

.main-content-inner {
    max-width: 750px;
}

/* Article List */
.articles-list {
    display: flex;
    flex-direction: column;
}

.article-item {
    margin-bottom: var(--spacing-3xl);
    padding-bottom: var(--spacing-3xl);
    border-bottom: 1px solid var(--border-light);
}

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

.article-date {
    font-size: 14px;
    color: var(--text-muted);
    margin-bottom: var(--spacing-sm);
    font-weight: 500;
    letter-spacing: 0.02em;
}

.article-item h2 {
    font-size: 28px;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: var(--spacing-md);
    letter-spacing: -0.03em;
    line-height: 1.2;
}

.article-item h2 a {
    color: var(--text-primary);
    text-decoration: none;
    transition: opacity 0.2s ease;
}

.article-item h2 a:hover {
    opacity: 0.6;
}

.article-item p {
    font-size: 16px;
    color: var(--text-secondary);
    line-height: 1.7;
}

/* Article Page Layout */
.article-page {
    max-width: 750px;
    margin: 0 auto;
    padding: var(--spacing-2xl) 40px;
    min-height: 100vh;
}

.back-link {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 16px;
    font-weight: 400;
    display: inline-block;
    margin-bottom: var(--spacing-2xl);
    transition: opacity 0.2s ease;
}

.back-link:hover {
    opacity: 0.7;
}

.article-header {
    margin-bottom: var(--spacing-2xl);
}

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

.article-header h1 {
    font-size: 42px;
    font-weight: 600;
    letter-spacing: -0.02em;
    line-height: 1.1;
    color: var(--text-primary);
    margin-bottom: var(--spacing-lg);
}

.article-content {
    font-size: 18px;
    line-height: 1.8;
    color: var(--text-secondary);
}

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

.article-content h2 {
    font-size: 32px;
    font-weight: 600;
    letter-spacing: -0.02em;
    line-height: 1.2;
    color: var(--text-primary);
    margin-top: var(--spacing-2xl);
    margin-bottom: var(--spacing-md);
}

.article-content h3 {
    font-size: 24px;
    font-weight: 600;
    letter-spacing: -0.01em;
    line-height: 1.3;
    color: var(--text-primary);
    margin-top: var(--spacing-xl);
    margin-bottom: var(--spacing-sm);
}

/* Responsive Design (RE-STABILIZED) */
@media (max-width: 968px) {
    .container {
        flex-direction: column;
        padding-left: 0;
        padding-right: 0;
    }

    .sidebar {
        width: 100%;
        position: relative;
        height: auto;
        padding: var(--spacing-xl) var(--spacing-lg);
        border-bottom: 1px solid var(--border-light);
    }

    .sidebar-content {
        max-width: 100%;
    }

    .sidebar h1 {
        font-size: 44px;
    }

    .sidebar nav {
        flex-direction: row;
        gap: var(--spacing-md);
    }

    .main-content {
        width: 100%;
        padding: var(--spacing-xl) var(--spacing-lg);
    }

    .article-item {
        margin-bottom: var(--spacing-2xl);
        padding-bottom: var(--spacing-2xl);
    }

    .article-page {
        padding: var(--spacing-xl) var(--spacing-lg);
    }

    .article-header h1 {
        font-size: 36px;
    }
}

@media (max-width: 640px) {
    .sidebar h1 {
        font-size: 36px;
    }

    .main-content {
        padding: var(--spacing-lg) var(--spacing-md);
    }

    .article-header h1 {
        font-size: 32px;
    }

    .article-content {
        font-size: 17px;
    }
}