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

body {
    font-family: system-ui, -apple-system, 'Segoe UI', sans-serif;
    color: #111;
    background-color: #f5f5f5;
    -webkit-font-smoothing: antialiased;
}

header {
    max-width: 720px;
    margin: 0 auto;
    padding: 3rem 2rem 0;
}

.profile-photo {
    width: 48px;
    height: 48px;
    border-radius: 50%;
    object-fit: cover;
}

main {
    max-width: 720px;
    margin: 0 auto;
    padding: 0 2rem 4rem;
}

/* Intro */
.intro {
    padding: 3rem 0 4rem;
}

.intro h1 {
    font-size: 2.2rem;
    font-weight: 700;
    line-height: 1.3;
    margin-bottom: 1.5rem;
    letter-spacing: -0.02em;
}

.intro .subtitle {
    font-size: 1.1rem;
    color: #555;
    margin-bottom: 0.5rem;
}

.intro .description {
    font-size: 1.1rem;
    color: #555;
}

.intro a {
    color: #111;
    text-decoration: underline;
    text-underline-offset: 2px;
}

.intro a:hover {
    color: #000;
}

/* Columns */
.columns {
    padding-top: 2rem;
}

.columns h2 {
    font-size: 0.95rem;
    font-weight: 400;
    color: #555;
    padding-bottom: 1rem;
    border-bottom: 1px solid #ddd;
    margin-bottom: 2rem;
}

.columns-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 2rem;
}

.column h3 {
    font-size: 1rem;
    font-weight: 700;
    margin-bottom: 0.75rem;
}

.column p {
    font-size: 0.9rem;
    color: #555;
    line-height: 1.6;
}

.column a {
    color: #555;
    text-decoration: none;
}

.column a:hover {
    color: #111;
    text-decoration: underline;
}

/* Responsive */
@media (max-width: 600px) {
    .intro h1 {
        font-size: 1.6rem;
    }

    .columns-grid {
        grid-template-columns: 1fr;
        gap: 2rem;
    }
}