:root {
    --paper-bg: #fffcf5;
    --line-color: rgba(0, 100, 255, 0.08);
    /* Faint blue */
    --margin-color: rgba(255, 0, 0, 0.12);
    /* Faint red */
    --text-primary: #2d3436;
    --text-secondary: #636e72;
    --accent-blue: #0984e3;
    --accent-dark: #74b9ff;
    --card-bg: #ffffff;
    --shadow-soft: 0 4px 15px rgba(0, 0, 0, 0.03);
    --baseline: 32px;
}

[data-theme="dark"] {
    --paper-bg: #1a1a1a;
    --line-color: rgba(255, 255, 255, 0.05);
    --margin-color: rgba(255, 71, 87, 0.2);
    --text-primary: #f5f6fa;
    --text-secondary: #dcdde1;
    --accent-blue: #70a1ff;
    --accent-dark: #1e90ff;
    --card-bg: #222222;
    --shadow-soft: 0 4px 15px rgba(0, 0, 0, 0.4);
}

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

body {
    font-family: 'Crimson Pro', serif;
    background-color: var(--paper-bg);
    color: var(--text-primary);
    line-height: var(--baseline);
    font-size: 20px;
    /* Slightly larger for the "pro" feel */
    transition: background-color 0.3s ease, color 0.3s ease;
    -webkit-font-smoothing: antialiased;
}

/* Theme Toggle */
.theme-toggle {
    position: fixed;
    top: 24px;
    right: 24px;
    z-index: 1000;
    background: var(--card-bg);
    border: 1px solid var(--line-color);
    border-radius: 50px;
    padding: 10px 20px;
    display: flex;
    align-items: center;
    cursor: pointer;
    box-shadow: var(--shadow-soft);
    font-size: 14px;
    font-weight: 500;
}

.theme-toggle i {
    margin-right: 8px;
    color: var(--accent-blue);
}

/* Paper Container with Ruler Lines */
.paper-container {
    max-width: 900px;
    margin: 64px auto;
    background: var(--paper-bg);
    padding: calc(var(--baseline) * 3) 100px;
    position: relative;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.05);
    border: 1px solid var(--line-color);
    box-sizing: border-box;
}

/* Vertical Margin Line */
.paper-container::before {
    content: '';
    position: absolute;
    top: 0;
    bottom: 0;
    left: 80px;
    width: 2px;
    background-color: var(--margin-color);
}

/* Horizontal Ruler Lines */
.paper-lines {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    pointer-events: none;
    background-image: linear-gradient(var(--line-color) 1px, transparent 1px);
    background-size: 100% var(--baseline);
    background-position: 0 calc(var(--baseline) * 3 - 6px);
    /* Adjusted to sit under character baseline */
    opacity: 0.8;
}

.content-wrapper {
    position: relative;
    z-index: 1;
}

.content-wrapper>* {
    margin-top: 0 !important;
}

/* Back Link */
.back-link {
    display: flex;
    align-items: center;
    gap: 8px;
    text-decoration: none;
    color: var(--text-secondary);
    font-size: 14px;
    height: var(--baseline);
    margin-bottom: var(--baseline);
    transition: color 0.2s ease;
    font-family: 'Inter', sans-serif;
}

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

/* Typography - Strict Vertical Rhythm */
h1 {
    font-size: 2.8rem;
    font-weight: 800;
    margin: 0 0 calc(var(--baseline) * 1);
    line-height: calc(var(--baseline) * 2);
    /* Takes 2 lines exactly */
    color: var(--text-primary);
    padding: 0;
}

h2 {
    font-size: 1.8rem;
    font-weight: 700;
    margin: calc(var(--baseline) * 2) 0 var(--baseline);
    line-height: var(--baseline);
    color: var(--text-primary);
    border-bottom: 2px solid var(--line-color);
    box-sizing: border-box;
    height: var(--baseline);
    /* Strict height to keep rhythm */
    display: flex;
    align-items: center;
}

h3 {
    font-size: 1.4rem;
    font-weight: 700;
    margin: var(--baseline) 0 var(--baseline);
    line-height: var(--baseline);
    color: var(--accent-blue);
    font-family: 'Inter', sans-serif;
}

p {
    margin: 0 0 var(--baseline) 0;
    font-size: 1.2rem;
    line-height: var(--baseline);
}

code {
    font-family: 'Inconsolata', monospace;
    background: rgba(0, 0, 0, 0.05);
    padding: 2px 6px;
    border-radius: 4px;
}

blockquote {
    border-left: 4px solid var(--accent-blue);
    padding: 0 var(--baseline);
    margin: var(--baseline) 0;
    background: var(--card-bg);
    font-style: italic;
    color: var(--text-secondary);
    box-shadow: var(--shadow-soft);
    line-height: var(--baseline);
    min-height: var(--baseline);
}

ul {
    margin-bottom: var(--baseline);
    padding-left: 1.5rem;
}

li {
    margin-bottom: 0;
    line-height: var(--baseline);
}

strong {
    color: var(--text-primary);
}

a {
    color: var(--accent-blue);
    text-decoration: none;
    border-bottom: 1px dashed var(--accent-blue);
    transition: all 0.2s ease;
}

a:hover {
    color: var(--accent-dark);
    border-bottom: 1px solid var(--accent-dark);
}

/* Project Card */
.project-card {
    background: var(--card-bg);
    border: 1px solid var(--line-color);
    border-radius: 12px;
    padding: var(--baseline);
    margin-top: calc(var(--baseline) * 2);
    box-shadow: var(--shadow-soft);
    line-height: var(--baseline);
}

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

.project-card p {
    margin-bottom: var(--baseline);
}

.project-card a {
    display: inline-block;
    margin-top: 0;
    font-weight: 600;
    border: none;
    background: var(--accent-blue);
    color: white !important;
    padding: 0 calc(var(--baseline) * 2);
    height: var(--baseline);
    border-radius: 6px;
    line-height: var(--baseline);
}

.project-card a:hover {
    background: var(--accent-dark);
    color: white;
}

/* Takeaway boxes */
.takeaway {
    background: rgba(9, 132, 227, 0.04);
    border-left: 4px solid var(--accent-blue);
    padding: var(--baseline);
    margin: var(--baseline) 0;
    font-family: 'Inter', sans-serif;
    font-size: 0.95rem;
}

.takeaway strong {
    color: var(--accent-blue);
    display: block;
    margin-bottom: 8px;
    font-weight: 700;
}

/* Footer */
footer {
    text-align: center;
    padding: 40px 0;
    color: var(--text-secondary);
    font-size: 14px;
}

/* Responsive */
@media (max-width: 768px) {
    .paper-container {
        padding: 40px 30px;
        margin: 20px 10px;
    }

    .paper-container::before {
        left: 20px;
    }

    h1 {
        font-size: 2rem;
    }
}