/* ===== Reset & base ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
    --bg: #fafafa;
    --surface: #ffffff;
    --text: #1c1c1e;
    --text-secondary: #6b7280;
    --accent: #2563eb;
    --accent-hover: #1d4ed8;
    --border: #e5e7eb;
    --tag-bg: #f3f4f6;
    --green: #059669;
    --green-bg: #d1fae5;
    --radius: 10px;
    --max-w: 760px;
    --nav-h: 56px;
}

html { scroll-behavior: smooth; }

body {
    font-family: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.65;
    font-size: 15px;
    -webkit-font-smoothing: antialiased;
}

a { color: var(--accent); text-decoration: none; }
a:hover { color: var(--accent-hover); }

img { max-width: 100%; display: block; }

/* ===== Nav ===== */
.nav {
    position: sticky;
    top: 0;
    z-index: 100;
    background: rgba(250, 250, 250, 0.85);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border);
    height: var(--nav-h);
    display: flex;
    align-items: center;
}

.nav-inner {
    max-width: var(--max-w);
    width: 100%;
    margin: 0 auto;
    padding: 0 24px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.nav-name {
    font-weight: 600;
    font-size: 1rem;
    color: var(--text);
}

.nav-links {
    display: flex;
    gap: 28px;
    list-style: none;
}

.nav-links a {
    font-size: 0.88rem;
    color: var(--text-secondary);
    font-weight: 500;
    transition: color 0.2s;
}

.nav-links a:hover,
.nav-links a.active {
    color: var(--text);
}

.nav-toggle {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    padding: 4px;
}

.nav-toggle svg { display: block; }

/* ===== Layout ===== */
.container {
    max-width: var(--max-w);
    margin: 0 auto;
    padding: 0 24px;
}

.page-top {
    padding: 64px 0 40px;
}

.page-title {
    font-size: 1.75rem;
    font-weight: 700;
    margin-bottom: 8px;
    letter-spacing: -0.02em;
}

.page-subtitle {
    color: var(--text-secondary);
    font-size: 1rem;
    max-width: 520px;
}

/* ===== Home hero ===== */
.hero {
    padding: 80px 0 48px;
}

.hero-greeting {
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin-bottom: 8px;
}

.hero h1 {
    font-size: 2.4rem;
    font-weight: 700;
    letter-spacing: -0.03em;
    margin-bottom: 6px;
}

.hero .role {
    font-size: 1.15rem;
    color: var(--text-secondary);
    margin-bottom: 24px;
}

.hero .bio {
    font-size: 0.95rem;
    color: var(--text);
    max-width: 540px;
    margin-bottom: 32px;
    line-height: 1.7;
}

.hero-links {
    display: flex;
    gap: 12px;
    flex-wrap: wrap;
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    font-size: 0.88rem;
    font-weight: 500;
    padding: 9px 18px;
    border-radius: 8px;
    transition: all 0.2s;
    border: 1px solid transparent;
}

.btn-primary {
    background: var(--accent);
    color: #fff;
    border-color: var(--accent);
}

.btn-primary:hover {
    background: var(--accent-hover);
    color: #fff;
}

.btn-secondary {
    background: var(--surface);
    color: var(--text);
    border-color: var(--border);
}

.btn-secondary:hover {
    border-color: var(--text-secondary);
    color: var(--text);
}

/* ===== Highlights (home) ===== */
.highlights {
    padding-bottom: 64px;
}

.highlights-label {
    font-size: 0.78rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--text-secondary);
    margin-bottom: 20px;
}

.highlight-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 16px;
}

.highlight-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 24px;
}

.highlight-card .number {
    font-size: 1.6rem;
    font-weight: 700;
    color: var(--accent);
    margin-bottom: 4px;
}

.highlight-card .label {
    font-size: 0.85rem;
    color: var(--text-secondary);
}

/* ===== Skills grid (home) ===== */
.skills-section {
    padding-bottom: 72px;
}

.skill-groups {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 16px;
}

.skill-group {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 24px;
}

.skill-group h3 {
    font-size: 0.88rem;
    font-weight: 600;
    margin-bottom: 10px;
}

.skill-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
}

.skill-tag {
    font-size: 0.78rem;
    background: var(--tag-bg);
    color: var(--text-secondary);
    padding: 4px 10px;
    border-radius: 5px;
}

/* ===== Projects page ===== */
.projects-grid {
    padding-bottom: 72px;
}

.project-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 28px;
    margin-bottom: 16px;
    transition: box-shadow 0.2s;
}

.project-card:hover {
    box-shadow: 0 2px 12px rgba(0,0,0,0.05);
}

.project-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    gap: 12px;
    margin-bottom: 10px;
}

.project-card h3 {
    font-size: 1.1rem;
    font-weight: 600;
}

.badge {
    font-size: 0.72rem;
    font-weight: 600;
    padding: 3px 10px;
    border-radius: 20px;
    white-space: nowrap;
    flex-shrink: 0;
}

.badge-live { background: var(--green-bg); color: var(--green); }
.badge-ml { background: #dbeafe; color: var(--accent); }
.badge-scratch { background: #fef3c7; color: #d97706; }
.badge-backend { background: var(--tag-bg); color: var(--text-secondary); }

.project-card p {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin-bottom: 14px;
    line-height: 1.6;
}

.tags {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
    margin-bottom: 14px;
}

.tag {
    font-size: 0.76rem;
    background: var(--tag-bg);
    color: var(--text-secondary);
    padding: 3px 10px;
    border-radius: 4px;
}

.project-links {
    display: flex;
    gap: 16px;
    flex-wrap: wrap;
}

.project-links a {
    font-size: 0.85rem;
    font-weight: 500;
}

.live-link { color: var(--green) !important; font-weight: 600 !important; }

/* ===== Project detail page ===== */
.project-detail-header {
    padding: 48px 0 32px;
}

.back-link {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    font-size: 0.84rem;
    font-weight: 500;
    color: var(--text-secondary);
    margin-bottom: 20px;
}

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

.project-detail-header h1 {
    font-size: 1.6rem;
    font-weight: 700;
    letter-spacing: -0.02em;
    margin-bottom: 6px;
}

.project-detail-header .badges {
    display: flex;
    gap: 8px;
    margin-bottom: 16px;
}

.project-detail-header p {
    font-size: 0.92rem;
    color: var(--text-secondary);
    max-width: 600px;
    line-height: 1.65;
    margin-bottom: 16px;
}

.project-detail-links {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
    margin-bottom: 0;
}

.demo-section {
    padding-bottom: 48px;
}

.demo-section h2 {
    font-size: 0.78rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--text-secondary);
    margin-bottom: 16px;
}

.demo-frame {
    width: 100%;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    overflow: hidden;
    background: var(--surface);
}

.demo-frame iframe {
    width: 100%;
    height: calc(100vh - 280px);
    min-height: 500px;
    border: none;
    display: block;
}

/* project card link wrapper */
.project-card-link {
    text-decoration: none;
    color: inherit;
    display: block;
}

.project-card-link .project-card {
    cursor: pointer;
}

.project-card-link:hover .project-card {
    box-shadow: 0 2px 12px rgba(0,0,0,0.05);
    border-color: #d1d5db;
}

/* ===== Resume page ===== */
.resume-section {
    padding-bottom: 48px;
}

.resume-download {
    margin-bottom: 40px;
}

.timeline {
    position: relative;
    padding-left: 24px;
}

.timeline::before {
    content: "";
    position: absolute;
    left: 0;
    top: 6px;
    bottom: 6px;
    width: 2px;
    background: var(--border);
}

.timeline-item {
    position: relative;
    margin-bottom: 32px;
}

.timeline-item:last-child { margin-bottom: 0; }

.timeline-item::before {
    content: "";
    position: absolute;
    left: -24px;
    top: 7px;
    width: 10px;
    height: 10px;
    border-radius: 50%;
    background: var(--accent);
    border: 2px solid var(--bg);
}

.timeline-item h3 {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 2px;
}

.timeline-item .where {
    font-size: 0.88rem;
    color: var(--text-secondary);
}

.timeline-item .when {
    font-size: 0.8rem;
    color: var(--text-secondary);
    margin-bottom: 6px;
}

.timeline-item .details {
    font-size: 0.88rem;
    color: var(--text);
}

.resume-label {
    font-size: 0.78rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--text-secondary);
    margin-bottom: 20px;
}

/* ===== Contact page ===== */
.contact-section {
    padding-bottom: 72px;
}

.contact-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 32px;
}

.contact-info h3 {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 12px;
}

.contact-info p {
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin-bottom: 20px;
    line-height: 1.6;
}

.contact-links {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.contact-links a {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    font-size: 0.9rem;
    color: var(--text);
}

.contact-links svg {
    flex-shrink: 0;
    color: var(--text-secondary);
}

.contact-form {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 28px;
}

.form-group {
    margin-bottom: 16px;
}

.form-group label {
    display: block;
    font-size: 0.84rem;
    font-weight: 500;
    margin-bottom: 6px;
    color: var(--text);
}

.form-group input,
.form-group textarea {
    width: 100%;
    font-family: inherit;
    font-size: 0.9rem;
    padding: 10px 14px;
    border: 1px solid var(--border);
    border-radius: 8px;
    background: var(--bg);
    color: var(--text);
    outline: none;
    transition: border-color 0.2s;
}

.form-group input:focus,
.form-group textarea:focus {
    border-color: var(--accent);
}

.form-group textarea {
    resize: vertical;
    min-height: 120px;
}

.form-submit {
    width: 100%;
}

/* ===== Footer ===== */
.footer {
    border-top: 1px solid var(--border);
    padding: 24px 0;
    margin-top: 16px;
}

.footer-inner {
    max-width: var(--max-w);
    margin: 0 auto;
    padding: 0 24px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 0.82rem;
    color: var(--text-secondary);
}

.footer-inner a { color: var(--text-secondary); }
.footer-inner a:hover { color: var(--text); }
/* ===== Posts / Blog ===== */
.posts-list { display: flex; flex-direction: column; gap: 1px; }
.post-card {
    display: block;
    padding: 24px 0;
    border-bottom: 1px solid var(--border);
    text-decoration: none;
    color: inherit;
    transition: background 0.15s;
}
.post-card:first-child { border-top: 1px solid var(--border); }
.post-card:hover { background: rgba(0,0,0,0.02); }
.post-card h2 {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text);
    margin-bottom: 6px;
}
.post-card p {
    font-size: 0.9rem;
    color: var(--text-secondary);
    line-height: 1.5;
}
.post-meta {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 6px;
    font-size: 0.8rem;
    color: var(--text-secondary);
}
.post-tag {
    background: var(--border);
    padding: 2px 8px;
    border-radius: 4px;
    font-size: 0.75rem;
}
.posts-empty {
    padding: 48px 0;
    text-align: center;
    color: var(--text-secondary);
    font-size: 0.95rem;
}

/* Post detail page */
.post-content {
    max-width: 680px;
    margin: 0 auto;
    line-height: 1.75;
    font-size: 1rem;
    color: var(--text);
}
.post-content h2 {
    font-size: 1.3rem;
    margin-top: 32px;
    margin-bottom: 12px;
}
.post-content h3 {
    font-size: 1.1rem;
    margin-top: 24px;
    margin-bottom: 8px;
}
.post-content p { margin-bottom: 16px; }
.post-content code {
    background: var(--border);
    padding: 2px 6px;
    border-radius: 4px;
    font-size: 0.9em;
}
.post-content pre {
    background: #1e1e1e;
    color: #d4d4d4;
    padding: 16px;
    border-radius: 8px;
    overflow-x: auto;
    margin-bottom: 16px;
    font-size: 0.85rem;
    line-height: 1.5;
}
.post-content pre code {
    background: none;
    padding: 0;
}
.post-content ul, .post-content ol {
    margin-bottom: 16px;
    padding-left: 24px;
}
.post-content li { margin-bottom: 6px; }
.post-header {
    max-width: 680px;
    margin: 0 auto 32px;
}
.post-header h1 {
    font-size: 1.8rem;
    margin-bottom: 8px;
}
.post-header .post-meta { margin-bottom: 16px; }

.footer-links { display: flex; gap: 16px; }
.footer-links a { color: var(--text-secondary); }
.footer-links a:hover { color: var(--text); }

/* ===== Responsive ===== */
@media (max-width: 640px) {
    .hero { padding: 48px 0 32px; }
    .hero h1 { font-size: 1.8rem; }
    .highlight-grid { grid-template-columns: 1fr; }
    .skill-groups { grid-template-columns: 1fr; }
    .contact-grid { grid-template-columns: 1fr; }
    .project-header { flex-direction: column; gap: 6px; }

    .nav-links { display: none; }
    .nav-links.open {
        display: flex;
        flex-direction: column;
        position: absolute;
        top: var(--nav-h);
        left: 0;
        right: 0;
        background: var(--bg);
        border-bottom: 1px solid var(--border);
        padding: 16px 24px;
        gap: 16px;
    }
    .nav-toggle { display: block; }
}