/* ========================================
   Academic Theme - Custom CSS
   Clean, modern, professional academic website
   ======================================== */

/* ========== ROOT VARIABLES ========== */
:root {
    --primary-color: #1a5490;
    --secondary-color: #2874a6;
    --accent-color: #d35400;
    --text-color: #2c3e50;
    --text-light: #7f8c8d;
    --bg-color: #ffffff;
    --bg-light: #f8f9fa;
    --border-color: #dee2e6;
    --shadow: 0 2px 4px rgba(0,0,0,0.1);
    --shadow-hover: 0 4px 8px rgba(0,0,0,0.15);
    --max-width: 1200px;
    --font-main: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen', 'Ubuntu', 'Cantarell', sans-serif;
    --font-mono: 'Courier New', Courier, monospace;
}

/* ========== GLOBAL STYLES ========== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-main);
    font-size: 16px;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--bg-color);
}

/* ========== NAVIGATION ========== */
.navbar {
    background: var(--bg-color);
    border-bottom: 1px solid var(--border-color);
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: var(--shadow);
}

.nav-container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-brand {
    display: flex;
    align-items: center;
    text-decoration: none;
    color: var(--text-color);
}

.nav-avatar {
    width: 45px;
    height: 45px;
    border-radius: 50%;
    margin-right: 1rem;
    border: 2px solid var(--primary-color);
}

.nav-title {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--primary-color);
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 2rem;
}

.nav-links a {
    text-decoration: none;
    color: var(--text-color);
    font-weight: 500;
    transition: color 0.3s;
    padding: 0.5rem 0;
}

.nav-links a:hover {
    color: var(--primary-color);
}

/* Mobile menu toggle */
.nav-toggle {
    display: none;
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--text-color);
}

@media (max-width: 768px) {
    .nav-toggle {
        display: block;
    }

    .nav-links {
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: var(--bg-color);
        flex-direction: column;
        gap: 0;
        padding: 1rem 0;
        box-shadow: var(--shadow);
        display: none;
    }

    .nav-links.active {
        display: flex;
    }

    .nav-links a {
        padding: 1rem 2rem;
        border-bottom: 1px solid var(--border-color);
    }
}

/* ========== MAIN CONTENT ========== */
.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 2rem;
}

.page-header {
    text-align: center;
    margin-bottom: 3rem;
    padding: 2rem 0;
}

.page-title {
    font-size: 2.5rem;
    color: var(--primary-color);
    margin-bottom: 0.5rem;
    font-weight: 700;
}

.page-subtitle {
    font-size: 1.2rem;
    color: var(--text-light);
}

/* ========== HOME PAGE ========== */
.hero-section {
    text-align: center;
    padding: 4rem 2rem;
    background: linear-gradient(135deg, var(--bg-light) 0%, var(--bg-color) 100%);
}

.hero-avatar {
    width: 150px;
    height: 150px;
    border-radius: 50%;
    margin-bottom: 1.5rem;
    border: 4px solid var(--primary-color);
    box-shadow: var(--shadow);
}

.hero-title {
    font-size: 3rem;
    color: var(--primary-color);
    margin-bottom: 0.5rem;
    font-weight: 700;
}

.hero-subtitle {
    font-size: 1.5rem;
    color: var(--text-light);
    margin-bottom: 2rem;
}

.hero-description {
    max-width: 800px;
    margin: 0 auto 2rem;
    font-size: 1.1rem;
    line-height: 1.8;
    color: var(--text-color);
}

/* ========== CONTENT SECTIONS ========== */
.content-section {
    margin-bottom: 3rem;
}

.section-title {
    font-size: 2rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
    padding-bottom: 0.5rem;
    border-bottom: 3px solid var(--accent-color);
}

/* ========== CARDS ========== */
.card {
    background: var(--bg-color);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 1.5rem;
    margin-bottom: 1.5rem;
    box-shadow: var(--shadow);
    transition: all 0.3s ease;
}

.card:hover {
    box-shadow: var(--shadow-hover);
    transform: translateY(-2px);
}

.card-title {
    font-size: 1.3rem;
    color: var(--primary-color);
    margin-bottom: 0.5rem;
    font-weight: 600;
}

.card-meta {
    color: var(--text-light);
    font-size: 0.9rem;
    margin-bottom: 0.75rem;
}

.card-text {
    color: var(--text-color);
    line-height: 1.7;
}

/* ========== BLOG POSTS ========== */
.post-list {
    list-style: none;
}

.post-item {
    margin-bottom: 2rem;
    padding-bottom: 2rem;
    border-bottom: 1px solid var(--border-color);
}

.post-item:last-child {
    border-bottom: none;
}

.post-title {
    font-size: 1.8rem;
    margin-bottom: 0.5rem;
}

.post-title a {
    color: var(--primary-color);
    text-decoration: none;
    transition: color 0.3s;
}

.post-title a:hover {
    color: var(--secondary-color);
}

.post-date {
    color: var(--text-light);
    font-size: 0.9rem;
    margin-bottom: 1rem;
}

.post-excerpt {
    color: var(--text-color);
    line-height: 1.7;
    margin-bottom: 1rem;
}

.read-more {
    display: inline-block;
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s;
}

.read-more:hover {
    color: var(--secondary-color);
}

/* ========== FOOTER ========== */
.footer {
    background: var(--bg-light);
    border-top: 1px solid var(--border-color);
    padding: 2rem 0;
    margin-top: 4rem;
}

.footer-container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 2rem;
    text-align: center;
}

.social-links {
    display: flex;
    justify-content: center;
    gap: 1.5rem;
    margin-bottom: 1rem;
}

.social-links a {
    color: var(--text-light);
    font-size: 1.5rem;
    transition: color 0.3s;
}

.social-links a:hover {
    color: var(--primary-color);
}

.footer-text {
    color: var(--text-light);
    font-size: 0.9rem;
}

.footer-text a {
    color: var(--primary-color);
    text-decoration: none;
}

.footer-text a:hover {
    text-decoration: underline;
}

/* ========== TYPOGRAPHY ========== */
h1, h2, h3, h4, h5, h6 {
    line-height: 1.3;
    margin-top: 1.5rem;
    margin-bottom: 1rem;
    font-weight: 600;
}

h1 { font-size: 2.5rem; }
h2 { font-size: 2rem; }
h3 { font-size: 1.75rem; }
h4 { font-size: 1.5rem; }
h5 { font-size: 1.25rem; }
h6 { font-size: 1.1rem; }

p {
    margin-bottom: 1rem;
}

a {
    color: var(--primary-color);
    text-decoration: none;
    transition: color 0.3s;
}

a:hover {
    color: var(--secondary-color);
}

/* ========== LISTS ========== */
ul, ol {
    margin-left: 2rem;
    margin-bottom: 1rem;
}

li {
    margin-bottom: 0.5rem;
}

/* ========== CODE ========== */
code {
    background: var(--bg-light);
    padding: 0.2rem 0.4rem;
    border-radius: 3px;
    font-family: var(--font-mono);
    font-size: 0.9em;
    color: var(--accent-color);
}

pre {
    background: var(--bg-light);
    padding: 1rem;
    border-radius: 5px;
    overflow-x: auto;
    margin-bottom: 1rem;
}

pre code {
    background: none;
    padding: 0;
    color: var(--text-color);
}

/* ========== TABLES ========== */
table {
    width: 100%;
    border-collapse: collapse;
    margin-bottom: 1.5rem;
    box-shadow: var(--shadow);
}

th, td {
    padding: 0.75rem;
    text-align: left;
    border-bottom: 1px solid var(--border-color);
}

th {
    background: var(--primary-color);
    color: white;
    font-weight: 600;
}

tr:hover {
    background: var(--bg-light);
}

/* ========== BUTTONS ========== */
.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: 5px;
    font-size: 1rem;
    font-weight: 500;
    text-decoration: none;
    cursor: pointer;
    transition: all 0.3s ease;
}

.btn:hover {
    background: var(--secondary-color);
    transform: translateY(-2px);
    box-shadow: var(--shadow-hover);
}

.btn-secondary {
    background: var(--accent-color);
}

.btn-secondary:hover {
    background: #c0392b;
}

/* ========== RESPONSIVE ========== */
@media (max-width: 768px) {
    .hero-title {
        font-size: 2rem;
    }

    .hero-subtitle {
        font-size: 1.2rem;
    }

    .page-title {
        font-size: 2rem;
    }

    .container {
        padding: 1rem;
    }

    .hero-section {
        padding: 2rem 1rem;
    }
}

/* ========== CONFERENCE TABLE (Custom) ========== */
.conference-table {
    width: 100%;
    max-width: 1800px;
    margin: 20px auto;
    border-collapse: collapse;
    box-shadow: var(--shadow);
}

.conference-table th {
    background-color: #6c757d;
    color: white;
    padding: 12px;
    text-align: left;
    font-weight: 600;
}

.conference-table td {
    padding: 10px 12px;
    border-bottom: 1px solid var(--border-color);
}

.conference-table tr:hover {
    background-color: var(--bg-light);
}

.conference-table a {
    color: var(--primary-color);
    text-decoration: none;
}

.conference-table a:hover {
    text-decoration: underline;
}

/* ========== UTILITIES ========== */
.text-center {
    text-align: center;
}

.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }
.mt-4 { margin-top: 2rem; }

.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }
.mb-4 { margin-bottom: 2rem; }