:root {
    --bg-color: #ffffff;
    --text-color: #1a1a1a;
    --text-muted: #555555;
    --nav-bg: #ffffff;
    --border-color: #e5e5e5;
    --hover-bg: #f9f9f9;
    --card-bg: #ffffff;
    --active-color: #000000;
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    padding: 0;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    color: var(--text-color);
    background-color: var(--bg-color);
    line-height: 1.6;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    margin-top: 1.5em;
    margin-bottom: 0.5em;
    font-weight: 600;
    line-height: 1.25;
}

h1 { font-size: 2.25em; }
h2 { font-size: 1.5em; border-bottom: 1px solid var(--border-color); padding-bottom: 0.3em; margin-top: 2em; }
h3 { font-size: 1.25em; }

p, ul, ol {
    margin-top: 0;
    margin-bottom: 1em;
}

a {
    color: var(--text-color);
    text-decoration: underline;
    text-decoration-color: var(--border-color);
    text-underline-offset: 2px;
}
a:hover {
    text-decoration-color: var(--text-color);
}

/* Layout */
.site-header {
    position: sticky;
    top: 0;
    background-color: var(--nav-bg);
    border-bottom: 1px solid var(--border-color);
    z-index: 1000;
}

.site-nav {
    display: flex;
    justify-content: center;
    padding: 1rem;
    overflow-x: auto;
}

.nav-container {
    display: flex;
    gap: 1.5rem;
    white-space: nowrap;
}

.nav-link {
    color: var(--text-muted);
    text-decoration: none;
    font-weight: 500;
    font-size: 1rem;
    transition: color 0.2s ease;
}

.nav-link:hover {
    color: var(--text-color);
}

.nav-link.active {
    color: var(--active-color);
    font-weight: 600;
}

.page-content {
    padding: 2rem 1.5rem;
}

.wrapper {
    max-width: 800px;
    margin: 0 auto;
}

/* Cards (for Experience, Patents, Projects) */
.card-list {
    list-style: none;
    padding: 0;
}

.card-list > li {
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    padding: 1.5rem;
    margin-bottom: 1rem;
    box-shadow: 0 1px 3px rgba(0,0,0,0.05);
}

.card-list > li:last-child {
    margin-bottom: 0;
}

.card-list > li > p:first-child {
    margin-top: 0;
}
.card-list > li > p:last-child {
    margin-bottom: 0;
}
.card-list > li ul, .card-list > li ol {
    margin-bottom: 0;
    margin-top: 0.5rem;
}

/* Lists */
ul, ol {
    padding-left: 1.5rem;
}

/* Footer */
.site-footer {
    padding: 2rem;
}

@media (max-width: 600px) {
    .site-nav {
        justify-content: flex-start;
    }
    h1 { font-size: 1.75em; }
    h2 { font-size: 1.25em; }
}