/* 
 * Minimal Personal Website
 * Pure CSS, no frameworks
 */

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

:root {
    --text: #1a1a1a;
    --text-secondary: #666;
    --background: #ffff;
    --link: #0066cc;
    --link-hover: #004499;
    --border: #e0e0e0;
    --max-width: 640px;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    font-size: 16px;
    line-height: 1.6;
    color: var(--text);
    background: var(--background);
}

/* Navigation */
header {
    position: sticky;
    top: 0;
    background: var(--background);
    border-bottom: 1px solid var(--border);
    z-index: 100;
}

nav {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 1rem 1.5rem;
    display: flex;
    gap: 2rem;
}

nav a {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.875rem;
}

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

/* Main Content */
main {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 1.5rem;
}

/* Hero Section */
.hero {
    padding: 4rem 0 3rem;
    border-bottom: 1px solid var(--border);
}

.hero h1 {
    font-size: 2rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.tagline {
    color: var(--text-secondary);
    font-size: 1.125rem;
    margin-bottom: 1rem;
}

.bio {
    margin-bottom: 1.5rem;
}

.links {
    display: flex;
    gap: 1.5rem;
}

.links a {
    color: var(--link);
    text-decoration: none;
}

.links a:hover {
    text-decoration: underline;
}

/* Projects Section */
#projects {
    padding: 2rem 0;
}

/* Interests Section */
#interests {
    padding: 2rem 0;
    border-top: 1px solid var(--border);
}

#interests h2 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.section-intro {
    color: var(--text-secondary);
    margin-bottom: 2rem;
}

.interest-category {
    padding: 1.5rem 0;
    border-bottom: 1px solid var(--border);
}

.interest-category:last-child {
    border-bottom: none;
}

.interest-category h3 {
    font-size: 1.125rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: var(--text);
}

.interest-category ul {
    list-style: disc;
    padding-left: 1.5rem;
    margin-top: 0.5rem;
}

.interest-category li {
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: 0.25rem;
}

.interest-category p {
    color: var(--text-secondary);
    line-height: 1.6;
}

/* Category */
.category {
    padding: 2rem 0;
    border-bottom: 1px solid var(--border);
}

.category:last-child {
    border-bottom: none;
}

.category h2 {
    font-size: 1.125rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: var(--text);
    display: inline;
}

.category > div {
    margin-top: 1rem;
}

.category-note {
    color: var(--text-secondary);
    font-size: 0.875rem;
    margin-bottom: 1rem;
}

/* Collapsible */
.collapsible {
    margin-top: 0.5rem;
}

.collapsible summary {
    cursor: pointer;
    color: var(--link);
    font-size: 0.875rem;
    padding: 0.5rem 0;
    list-style: none;
}

.collapsible summary::-webkit-details-marker {
    display: none;
}

.collapsible summary::before {
    content: "+ ";
}

.collapsible[open] summary::before {
    content: "− ";
}

.collapsible summary:hover {
    text-decoration: underline;
}

/* Project List */
.project-list {
    list-style: none;
}

.project {
    padding: 1rem 0;
    border-bottom: 1px solid var(--border);
}

.project:last-child {
    border-bottom: none;
}

.project a {
    color: var(--link);
    text-decoration: none;
    font-weight: 500;
}

.project a:hover {
    text-decoration: underline;
}

.project-title {
    font-weight: 500;
    color: var(--text);
}

.company,
.course {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

.company::before {
    content: " ";
}

.year {
    color: var(--text-secondary);
    font-size: 0.875rem;
    margin-left: 0.5rem;
}

.status {
    display: inline-block;
    width: 8px;
    height: 8px;
    border-radius: 50%;
    margin-left: 0.5rem;
    vertical-align: middle;
}

.status.active {
    background-color: #22c55e;
}

.status.inactive {
    background-color: var(--text-secondary);
}

.project p {
    margin-top: 0.5rem;
    color: var(--text-secondary);
    font-size: 0.9375rem;
}

/* Footer */
footer {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 3rem 1.5rem;
    border-top: 1px solid var(--border);
}

footer h2 {
    font-size: 1.125rem;
    font-weight: 600;
    margin-bottom: 1rem;
}

.contact-links {
    display: flex;
    flex-wrap: wrap;
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.contact-links a {
    color: var(--link);
    text-decoration: none;
}

.contact-links a:hover {
    text-decoration: underline;
}

.copyright {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

/* Responsive */
@media (max-width: 480px) {
    .hero {
        padding: 3rem 0 2rem;
    }

    .hero h1 {
        font-size: 1.75rem;
    }

    nav {
        gap: 1.5rem;
    }

    .contact-links {
        gap: 1rem;
    }
}