/* styles.css */
:root {
    --primary-color: #1a1423; /* Deep bluish-violet */
    --accent-color: #4b0082;  /* Indigo accent */
    --bg-color: #f8f9fa;
    --text-color: #222;
    --light-text: #555;
    --white: #ffffff;
}

body {
    font-family: 'Inter', system-ui, -apple-system, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--bg-color);
    margin: 0;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

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

a:hover {
    text-decoration: underline;
}

main a:hover {
    text-decoration: underline !important;
}

/* Ensure content links match the arXiv accent styling */
.item a,
.item-title a,
.item-details a {
    color: var(--accent-color) !important;
    text-decoration: none;
}

.item a:hover,
.item-title a:hover,
.item-details a:hover {
    text-decoration: underline;
}

.container { max-width: 900px; margin: 0 auto; padding: 0 20px; }

/* Header */
header {
    background-color: var(--primary-color);
    color: var(--white);
    padding: 40px 0; /* Reduced padding for subpages */
    text-align: center;
}

.profile-img {
    width: 150px;
    height: 150px;
    border-radius: 50%;
    object-fit: cover;
    border: 4px solid rgba(255,255,255,0.15);
    margin-bottom: 15px;
}

h1 { margin: 0; font-size: 2.2rem; font-weight: 700; letter-spacing: -0.5px; }
.subtitle { font-size: 1rem; color: #a19db1; font-weight: 300; margin-top: 5px; }

/* Navigation */
nav { margin-top: 25px; }
nav a { 
    color: #ccc; 
    margin: 0 12px; 
    text-decoration: none; 
    font-size: 0.9rem; 
    text-transform: uppercase; 
    letter-spacing: 1px; 
    transition: color 0.3s; 
    display: inline-block;
}
nav a:hover { color: var(--white); }
nav a.active { color: var(--white); border-bottom: 1px solid var(--accent-color); padding-bottom: 2px; }

/* Content Sections */
main { flex: 1; } /* Pushes footer down */

section {
    background: var(--white);
    padding: 40px;
    margin: 30px auto;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
    max-width: 900px;
}

h2 { 
    color: var(--primary-color); 
    font-size: 1.8rem; 
    margin-bottom: 25px; 
    position: relative;
    padding-bottom: 10px;
    border-bottom: 2px solid #f0f0f0;
}

h2::after {
    content: "";
    position: absolute;
    bottom: -3px;
    left: 0;
    width: 50px;
    height: 4px;
    background: var(--accent-color);
    border-radius: 2px;
}
h3 { font-size: 1.2rem; margin-top: 30px; color: var(--accent-color); font-weight: 600; }

/* Lists & Items */
ul { padding-left: 20px; margin-bottom: 20px; }
li { margin-bottom: 8px; }

.item { margin-bottom: 25px; }
.item-title { font-weight: 700; display: block; color: #000; font-size: 1rem; }
.item-details { font-size: 0.95rem; color: var(--light-text); display: block; margin-top: 4px; }
.tag { 
    display: inline-block; font-size: 0.75rem; background: #eef; 
    padding: 2px 8px; border-radius: 4px; color: var(--accent-color); 
    font-weight: 600; margin-right: 8px; vertical-align: middle;
}

/* Buttons */
.btn {
    display: inline-block;
    background: var(--primary-color);
    color: white;
    padding: 10px 24px;
    border-radius: 5px;
    text-decoration: none;
    font-size: 0.9rem;
    transition: background 0.3s;
    margin-right: 10px;
    margin-top: 5px;
}
.btn:hover { background: var(--accent-color); }

/* Animation Coin Flip */
.coin-container {
    width: 151px; /* +1px to fix border cropping or exact match */
    height: 151px;
    margin: 0 auto 15px;
    perspective: 1000px;
}

.coin {
    width: 100%;
    height: 100%;
    position: relative;
    transform-style: preserve-3d;
    animation: flip-coin 5s infinite ease-in-out;
}

.coin img.profile-img {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    backface-visibility: hidden;
    margin-bottom: 0; /* Remove margin from inner images */
}

.coin .front {
    transform: rotateY(0deg);
    z-index: 2;
}

.coin .back {
    transform: rotateY(180deg);
}

@keyframes flip-coin {
    0%, 70% {
        transform: rotateY(0deg);
    }
    100% {
        transform: rotateY(360deg);
    }
}
.btn-outline { background: transparent; border: 1px solid var(--primary-color); color: var(--primary-color); }
.btn-outline:hover { background: var(--primary-color); color: white; }

footer { 
    text-align: center; 
    padding: 30px 0; 
    color: #888; 
    font-size: 0.85rem; 
    background: #f1f1f1; 
    margin-top: auto; 
}

@media (max-width: 600px) {
    h1 { font-size: 1.8rem; }
    section { padding: 20px; margin: 15px; }
    nav a { display: block; margin: 10px 0; }
}