:root {
    --bg-color: #ffffff;
    --surface-color: #fafafa;
    --text-primary: #111827;
    --text-secondary: #6b7280;
    --border-color: #e5e7eb;
    --accent-color: #000000;
    --hover-bg: #f3f4f6;
    --card-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.05);
}

body.dark-mode {
    --bg-color: #0a0a0a;
    --surface-color: #121212;
    --text-primary: #ededed;
    --text-secondary: #a1a1aa;
    --border-color: #27272a;
    --accent-color: #ffffff;
    --hover-bg: #1f1f1f;
    --card-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.3);
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-primary);
    line-height: 1.6;
    transition: background-color 0.3s ease, color 0.3s ease;
    -webkit-font-smoothing: antialiased;
}

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

a:hover {
    color: var(--text-secondary);
}

/* --- Layout --- */
.container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 2rem;
}

/* --- Navbar --- */
nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 2rem 0;
    border-bottom: 1px solid var(--border-color);
    margin-bottom: 4rem;
}

.nav-brand {
    font-weight: 700;
    font-size: 1.25rem;
    letter-spacing: -0.02em;
}

.nav-links {
    display: flex;
    gap: 2rem;
    list-style: none;
    align-items: center;
}

.nav-links a {
    font-size: 0.95rem;
    font-weight: 500;
}

#theme-toggle {
    background: transparent;
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    padding: 0.4rem 0.8rem;
    border-radius: 6px;
    cursor: pointer;
    font-size: 0.85rem;
    font-weight: 500;
    transition: background-color 0.2s;
}

#theme-toggle:hover {
    background-color: var(--hover-bg);
}

/* --- Typography --- */
h1 {
    font-size: 3rem;
    font-weight: 700;
    line-height: 1.2;
    letter-spacing: -0.03em;
    margin-bottom: 1rem;
}

h2 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 2rem;
    letter-spacing: -0.02em;
}

h3 {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
}

p {
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
    font-size: 1.05rem;
}

/* --- Hero --- */
.hero {
    margin-bottom: 6rem;
    max-width: 700px;
}

/* --- Sections --- */
section {
    margin-bottom: 6rem;
}

/* --- Grids --- */
.grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 2rem;
}

/* --- Cards --- */
.card {
    background-color: var(--surface-color);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 2rem;
    transition: transform 0.2s ease, border-color 0.2s ease, box-shadow 0.2s ease;
    display: flex;
    flex-direction: column;
}

.card:hover {
    border-color: var(--text-primary);
    box-shadow: var(--card-shadow);
    transform: translateY(-2px);
}

.card-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 1rem;
}

.tech-badge {
    font-family: ui-monospace, SFMono-Regular, Consolas, monospace;
    font-size: 0.75rem;
    background-color: var(--hover-bg);
    color: var(--text-primary);
    padding: 0.25rem 0.6rem;
    border-radius: 4px;
    border: 1px solid var(--border-color);
}

.card p {
    font-size: 0.95rem;
    margin-bottom: 2rem;
    flex-grow: 1;
}

.card-link {
    font-size: 0.9rem;
    font-weight: 500;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.card-link::after {
    content: "→";
    transition: transform 0.2s ease;
}

.card-link:hover::after {
    transform: translateX(4px);
}

/* --- Skills --- */
.skills-list {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
    list-style: none;
}

.skills-list li {
    background-color: var(--surface-color);
    border: 1px solid var(--border-color);
    padding: 0.5rem 1rem;
    border-radius: 8px;
    font-size: 0.95rem;
    font-weight: 500;
}

/* --- Contact & Footer --- */
.contact-links {
    display: flex;
    gap: 1.5rem;
    margin-top: 2rem;
}

.contact-link {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-weight: 500;
    border-bottom: 1px solid transparent;
}

.contact-link:hover {
    border-bottom-color: var(--text-primary);
}

footer {
    border-top: 1px solid var(--border-color);
    padding: 2rem 0;
    text-align: center;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

/* --- Responsive --- */
@media screen and (max-width: 768px) {
    h1 {
        font-size: 2.25rem;
    }
    nav {
        flex-direction: column;
        gap: 1.5rem;
        padding: 1.5rem 0;
    }
    .nav-links {
        width: 100%;
        justify-content: center;
        flex-wrap: wrap;
    }
}