:root {
  --main-color: #059ef7;   
}
/* ==========================
   TWO COLUMN LAYOUT
========================== */

.home-layout{
    display:grid;
    grid-template-columns:340px 1fr;
    gap:30px;
    align-items:start;
}

/* LEFT PROFILE CARD */

.sidebar{
    position:sticky;
    top:20px;

    background:white;

    border-radius:12px;

    box-shadow:0 2px 8px rgba(0,0,0,.08);

    padding:18px;
}

.sidebar img{
    width:180px;
    height:180px;

    object-fit:cover;

    border-radius:50%;

    display:block;

    margin:0 auto 20px auto;

    border:4px solid var(--main-color);
}

.sidebar h2{
    text-align:center;

    border:none;

    margin-bottom:5px;
}

.sidebar h3{

    text-align:center;

    font-size:1rem;

    color:#666;

    font-weight:normal;

    margin-bottom:20px;
}

.profile-info{

    list-style:none;
}

.profile-info li{

    margin:8px 0;

    word-break:break-word;
}

.profile-info strong{

    color: var(--main-color);
}

.content section:first-child{

    margin-top:0;
}

@media(max-width:900px){

.home-layout{

grid-template-columns:1fr;

}

.sidebar{

position:relative;

top:0;

}

}
/* ==========================
   GLOBAL STYLES
========================== */

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

body {
    font-family: Arial, Helvetica, sans-serif;
    line-height: 1.7;
    color: #222;
    background-color: #f8f9fb;
}

/* ==========================
   HEADER
========================== */

header {
    background: var(--main-color);
    color: white;
    padding: 2rem 0;
    text-align: center;
}

header h1 {
    font-family: Georgia, serif;
    font-size: 2.5rem;
    margin-bottom: 0.5rem;
}

header p {
    font-size: 1.1rem;
}

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

nav {
    background: #ffffff;
    border-bottom: 1px solid #ddd;
}

nav ul {
    list-style: none;
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
}

nav li {
    margin: 0;
}

nav a {
    display: block;
    padding: 1rem 1.2rem;
    text-decoration: none;
    color: #003366;
    font-weight: bold;
    transition: 0.3s;
}

nav a:hover {
    background: var(--main-color);
    color: white;
}

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

main {
    max-width: 1100px;
    margin: auto;
    padding: 3rem 2rem;
}

section {
    margin-bottom: 1.5rem;
}

section h2 {
    font-family: Georgia, serif;
    color: var(--main-color);
    margin-bottom: 1rem;
    border-bottom: 2px solid var(--main-color);
    padding-bottom: 0.5rem;
}

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

.hero {
    text-align: center;
}

.hero img {
    width: 220px;
    height: 220px;
    object-fit: cover;
    border-radius: 50%;
    margin-bottom: 1rem;
    border: 5px solid var(--main-color);
}

.hero h2 {
    border: none;
    margin-bottom: 0.5rem;
}

.hero p {
    max-width: 700px;
    margin: auto;
}

/* ==========================
   RESEARCH INTERESTS
========================== */

.research-list {
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
}

.research-item {
    background: white;
    padding: 1rem;
    flex: 1;
    min-width: 250px;
    border-left: 5px solid var(--main-color);
    box-shadow: 0 2px 5px rgba(0,0,0,0.08);
}

/* ==========================
   PUBLICATIONS
========================== */

.publication {
    background: white;
    padding: 1rem;
    margin-bottom: 1rem;
    border-radius: 8px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.08);
}

.publication-title {
    font-weight: bold;
    color: var(--main-color);
}

.publication-links a {
    text-decoration: none;
    margin-right: 1rem;
    color: #0066cc;
}

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

/* ==========================
   COLLABORATORS
========================== */

.collaborator-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1rem;
}

.collaborator-card {
    background: white;
    padding: 1rem;
    border-radius: 10px;
    text-align: center;
    box-shadow: 0 3px 8px rgba(0,0,0,0.08);
}

.collaborator-card img {
    width: 120px;
    height: 120px;
    object-fit: cover;
    border-radius: 50%;
    margin-bottom: 1rem;
}

/* ==========================
   BUTTONS
========================== */

.button {
    display: inline-block;
    background: var(--main-color);
    color: white;
    padding: 0.8rem 1.4rem;
    border-radius: 5px;
    text-decoration: none;
    transition: 0.3s;
}

.button:hover {
    background: #0055aa;
}

/* ==========================
   FOOTER
========================== */

footer {
    background: var(--main-color);
    color: white;
    text-align: center;
    padding: 2rem;
    margin-top: 3rem;
}

/* ==========================
   RESPONSIVE DESIGN
========================== */

@media (max-width: 768px) {

    header h1 {
        font-size: 2rem;
    }

    nav ul {
        flex-direction: column;
    }

    nav a {
        text-align: center;
        border-bottom: 1px solid #eee;
    }

    main {
        padding: 2rem 1rem;
    }

    .hero img {
        width: 180px;
        height: 180px;
    }
}

/* ==========================
   INTRO SECTION
========================== */

.intro {
    display: flex;
    align-items: flex-start;
    gap: 40px;
    margin-bottom: 60px;
}

.intro-photo {
    flex: 0 0 240px;
}

.intro-photo img {
    width: 220px;
    border-radius: 50%;
    border: 5px solid var(--main-color);
}

.intro-content {
    flex: 1;
}

.intro-content h2 {
    border: none;
    margin-bottom: 10px;
}

.intro-content p {
    margin-bottom: 15px;
}

.button-group {
    display: flex;
    gap: 15px;
    flex-wrap: wrap;
}

/* Mobile */

@media (max-width: 768px) {

    .intro {
        flex-direction: column;
        text-align: center;
        align-items: center;
    }

    .intro-content {
        text-align: center;
    }

    .button-group {
        justify-content: center;
    }

}

/* ==========================
   PAPERS PAGE
========================== */

.year-heading{
    color:var(--main-color);
    font-family:Georgia, serif;
    margin:25px 0 15px 0;
    border-bottom:2px solid var(--main-color);
    padding-bottom:5px;
}

.paper-card{

    background:white;

    padding:18px;

    border-radius:10px;

    box-shadow:0 2px 6px rgba(0,0,0,.08);

    margin-bottom:18px;
}

.paper-title{

    font-size:1.15rem;

    font-weight:bold;

    color:var(--main-color);

    margin-bottom:8px;
}

.paper-authors{

    color:#555;

    margin-bottom:5px;
}

.paper-journal{

    font-style:italic;

    margin-bottom:10px;
}

.paper-links{

    display:flex;

    flex-wrap:wrap;

    gap:10px;
}

.paper-links a{

    text-decoration:none;

    color:#0055AA;

    font-weight:bold;
}

.paper-links a:hover{

    text-decoration:underline;
}

/* ==========================
   PAPERS FILTER
========================== */

.paper-controls{
    display:flex;
    flex-wrap:wrap;
    gap:15px;
    align-items:center;
    margin-bottom:25px;
}

.paper-search{
    flex:1;
    min-width:250px;
}

.paper-search input{
    width:100%;
    padding:10px 15px;
    border:1px solid #ccc;
    border-radius:8px;
    font-size:1rem;
}

.year-filters{
    display:flex;
    gap:8px;
    flex-wrap:wrap;
}

.filter-btn{

    padding:8px 15px;

    border:none;

    border-radius:20px;

    cursor:pointer;

    background:#e5e5e5;

    transition:.2s;
}

.filter-btn:hover{

    background:var(--main-color);

    color:white;
}

.filter-btn.active{

    background:var(--main-color);

    color:white;
}

.paper-count{

    margin:20px 0;

    color:#666;
}

/* ==========================
   STATISTICS
========================== */

.stats-grid{

    display:grid;

    grid-template-columns:repeat(auto-fit,minmax(140px,1fr));

    gap:15px;

    margin:20px 0 30px;
}

.stat-card{

    background:white;

    padding:15px;

    border-radius:10px;

    text-align:center;

    box-shadow:0 2px 6px rgba(0,0,0,.08);
}

.stat-number{

    font-size:2rem;

    color:var(--main-color);

    font-weight:bold;
}

.stat-label{

    color:#666;

    margin-top:5px;
}

/* ==========================
   CONTACT PAGE
========================== */

.contact-grid{

    display:grid;

    grid-template-columns:1fr 1fr;

    gap:25px;

    margin:30px 0;

}

.contact-card{

    background:white;

    padding:25px;

    border-radius:10px;

    box-shadow:0 2px 8px rgba(0,0,0,.08);

}

.contact-card h3{

    margin-top:0;

}

.profile-links{

    list-style:none;

    padding:0;

}

.profile-links li{

    margin:12px 0;

}

.profile-links a{

    text-decoration:none;

    color:#0055AA;

    font-weight:bold;

}

.profile-links a:hover{

    text-decoration:underline;

}

.map-placeholder{

    background:white;

    height:300px;

    border-radius:10px;

    display:flex;

    justify-content:center;

    align-items:center;

    box-shadow:0 2px 8px rgba(0,0,0,.08);

    color:#666;

    margin-top:20px;

}

@media(max-width:800px){

.contact-grid{

grid-template-columns:1fr;

}

}