/* --- Variables & Core Setup --- */
:root {
    --bg-color: #ffffff;
    --text-color: #1a1a1a;
    --accent-color: #2563eb; 
    --secondary-text: #64748b;
    --border-color: #e2e8f0;
    --card-bg: #ffffff;
    --tag-bg: #f1f5f9;
    --code-tag-bg: #eff6ff;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }

body {
    font-family: 'Inter', sans-serif;
    line-height: 1.7;
    color: var(--text-color);
    background-color: var(--bg-color);
    /* Scientific Grid Background */
    background-image: radial-gradient(var(--border-color) 1px, transparent 1px);
    background-size: 30px 30px;
    min-height: 100vh;
}

.container { max-width: 900px; margin: 0 auto; padding: 0 1.5rem; }

/* --- Navigation & Header --- */
header {
    background: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(8px);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 100;
    padding: 1rem 0;
}

.nav-container { display: flex; justify-content: space-between; align-items: center; }
.logo { font-weight: 800; color: var(--text-color); text-decoration: none; letter-spacing: 1px; font-size: 1.1rem; cursor: pointer; }

.tab-menu { display: flex; list-style: none; gap: 1rem; align-items: center; }

.tab-link {
    background: none;
    border: none;
    font-family: inherit;
    font-size: 0.95rem;
    font-weight: 500;
    cursor: pointer;
    color: var(--secondary-text);
    padding: 8px 4px;
    transition: 0.2s;
    border-bottom: 2px solid transparent;
}

.tab-link:hover { color: var(--accent-color); }
.tab-link.active { color: var(--accent-color); border-bottom: 2px solid var(--accent-color); }

.btn-contact {
    background: var(--text-color);
    color: #fff !important;
    padding: 0.5rem 1rem;
    border-radius: 6px;
    text-decoration: none;
    font-size: 0.9rem;
    font-weight: 500;
    transition: background 0.2s;
}
.btn-contact:hover { background: var(--accent-color); }

/* --- Tab Transitions --- */
.tab-content {
    display: none;
    opacity: 0;
    transform: translateY(10px);
    transition: opacity 0.4s ease, transform 0.4s ease;
}

.tab-content.active {
    display: block;
    opacity: 1;
    transform: translateY(0);
}

/* --- Content Styling --- */
section { padding: 4rem 0 2rem; }

h1 { font-size: 3.5rem; font-weight: 800; line-height: 1.1; margin-bottom: 1.5rem; }
.highlight { color: var(--accent-color); }
.subtitle { font-size: 1.25rem; color: var(--secondary-text); margin-bottom: 1.5rem; }

h2 { font-size: 1.3rem; margin-bottom: 2rem; text-transform: uppercase; letter-spacing: 2px; color: var(--secondary-text); }

.tag, .tag-tech {
    display: inline-block;
    background: var(--tag-bg);
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 500;
    margin-right: 8px;
    margin-bottom: 8px;
}

.tag-tech { font-family: 'Fira Code', monospace; background: var(--code-tag-bg); color: #1e40af; }

/* --- Bio Section Layout with Circular Headshot --- */
.bio-layout {
    display: flex;
    align-items: center;
    gap: 2rem;
}

.headshot-wrapper {
    flex-shrink: 0;
    width: 200px;
    height: 200px;
}

.headshot {
    width: 100%;
    height: 100%;
    border-radius: 50%;
    object-fit: cover;
    border: 3px solid var(--border-color);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
}

/* --- Cards & Grids --- */
.card {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    padding: 2rem;
    border-radius: 12px;
}

.card-header { display: flex; justify-content: space-between; align-items: center; margin-bottom: 0.5rem; }
.date { font-size: 0.85rem; color: var(--secondary-text); font-weight: 600; }
.role { font-weight: bold; color: var(--accent-color); margin-bottom: 1rem; }

.project-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 1.5rem; }
.project-card {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    padding: 1.5rem;
    border-radius: 12px;
    transition: 0.3s;
}
.project-card:hover { border-color: var(--accent-color); transform: translateY(-4px); box-shadow: 0 10px 20px rgba(0,0,0,0.05); }
.project-card h3 { margin-bottom: 0.75rem; }

/* --- Resume Tab Styles --- */
.resume-controls {
    margin-bottom: 2rem;
    padding: 1.5rem;
    background: var(--tag-bg);
    border-radius: 12px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 1rem;
}

.resume-controls p { margin: 0; color: var(--secondary-text); font-size: 0.95rem; }

.btn-resume {
    background: var(--accent-color);
    color: white !important;
    padding: 0.8rem 1.5rem;
    border-radius: 6px;
    text-decoration: none;
    font-weight: 600;
    transition: 0.2s;
    white-space: nowrap;
}

.btn-resume:hover { background: #1d4ed8; transform: translateY(-2px); }

.resume-viewer {
    border: 1px solid var(--border-color);
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 4px 12px rgba(0,0,0,0.05);
}

/* --- Footer --- */
footer { padding: 4rem 0; border-top: 1px solid var(--border-color); text-align: center; color: var(--secondary-text); font-size: 0.9rem; }

/* --- Responsive Layouts --- */
@media (max-width: 650px) {
    h1 { font-size: 2.4rem; }
    
    .nav-container { flex-direction: column; gap: 1rem; }
    .tab-menu { font-size: 0.85rem; gap: 0.5rem; }

    .bio-layout {
        flex-direction: column;
        text-align: center;
        gap: 1.5rem;
    }

    .headshot-wrapper {
        width: 150px;
        height: 150px;
    }

    .resume-controls {
        flex-direction: column;
        text-align: center;
    }
    
    .resume-viewer {
        display: none;
    }
}