/* ===== GLOBAL ===== */

body {
    background: #121212;
    color: #eaeaea;
    font-family: Georgia, serif;
    margin: 0;
    overflow-x: hidden;
}

h1, h2, h3 {
    color: #ffffff;
}

p {
    line-height: 1.7;
}

/* ===== NAVIGATION ===== */

.nav-header {
    padding: 20px;
}

.back-link {
    color: #888;
    text-decoration: none;
    transition: 0.2s;
}

.back-link:hover {
    color: #6a0dad;
}

/* ===== HERO ===== */

.hero {
    text-align: center;
    padding: 40px 20px;
}

.profile-img {
    width: 180px;
    height: 180px;
    border-radius: 50%;
    border: 3px solid #6a0dad;
    object-fit: cover;
}

.tagline {
    color: #aaa;
    margin-top: 10px;
}

/* ===== CONTENT ===== */

.content {
    max-width: 900px;
    margin: auto;
    padding: 20px;
}

/* ===== GRID ===== */

.grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 20px;
    padding: 40px;
    max-width: 900px;
    margin: auto;
}

/* ===== CARDS ===== */

.card {
    display: block;
    padding: 20px;
    border-radius: 12px;
    text-decoration: none;
    color: inherit;
    background: #1e1e1e;
    border: 1px solid #333;
    transition: 0.2s ease;
}

.card:hover {
    transform: translateY(-5px);
    border-color: #6a0dad;
    box-shadow: 0 4px 12px rgba(0,0,0,0.5);
}

.card h2 {
    margin-top: 0;
}

/* ===== LINKS ===== */

a {
    color: #8ab4f8;
}

a:hover {
    text-decoration: underline;
}

/* ===== TOPIC LISTS ===== */

details {
    background: #1e1e1e;
    border: 1px solid #333;
    border-radius: 10px;
    margin-bottom: 15px;
    padding: 15px;
}

details:hover {
    border-color: #6a0dad;
}

summary {
    cursor: pointer;
    font-size: 1.15rem;
    font-weight: bold;
}

/* ===== TUTORING ===== */

.tutoring-list li {
    margin-bottom: 10px;
}

.poster {
    text-align: center;
    margin: 50px auto;
}

.poster-img {
    max-width: 700px;
    width: 90%;
    border-radius: 12px;
    border: 1px solid #333;
}

/* ===== RESEARCH GRAPH ===== */

.graph-container {
    display: flex;
    justify-content: center;
    margin: 60px 0;
}

.graph-container svg {
    width: 500px;
    height: 500px;
}

/* Graph edges */

.graph polygon,
.graph line {
    fill: none;
    stroke: #cfcfcf;
    stroke-width: 2.5;
    stroke-linejoin: round;
    stroke-linecap: round;
}

/* Graph vertices */

.graph circle {
    fill: #ff6b6b;
    stroke: #121212;
    stroke-width: 2;
}

/* ===== MOBILE ===== */

@media (max-width: 768px) {

    .profile-img {
        width: 140px;
        height: 140px;
    }

    .grid {
        padding: 20px;
    }

    .graph-container svg {
        width: 95%;
        height: auto;
    }
}