/* ========================================
   Tıpta Yapay Zeka - Professional Styles
   ======================================== */

:root {
    /* Colors */
    --primary: #2563eb;
    --primary-dark: #1e40af;
    --secondary: #7c3aed;
    --accent: #06b6d4;
    --success: #10b981;
    --warning: #f59e0b;
    --error: #ef4444;

    --dark: #0f172a;
    --dark-light: #1e293b;
    --gray: #64748b;
    --gray-light: #cbd5e1;
    --gray-lighter: #f1f5f9;
    --white: #ffffff;

    /* Gradients */
    --gradient-primary: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --gradient-blue: linear-gradient(135deg, #667eea 0%, #2563eb 100%);
    --gradient-purple: linear-gradient(135deg, #a855f7 0%, #7c3aed 100%);
    --gradient-cyan: linear-gradient(135deg, #06b6d4 0%, #3b82f6 100%);

    /* Spacing */
    --container-width: 1200px;
    --section-padding: 5rem 2rem;

    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1);

    /* Transitions */
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

/* ========================================
   Reset & Base
   ======================================== */

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

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    line-height: 1.6;
    color: var(--dark);
    background: var(--white);
    overflow-x: hidden;
}

h1, h2, h3, h4, h5, h6 {
    font-family: 'Poppins', sans-serif;
    font-weight: 700;
    line-height: 1.2;
}

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

img {
    max-width: 100%;
    height: auto;
}

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

/* ========================================
   Navigation
   ======================================== */

.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    box-shadow: var(--shadow-md);
    z-index: 1000;
    transition: var(--transition);
}

.navbar .container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 1rem 2rem;
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    font-size: 1.25rem;
}

.logo-icon {
    font-size: 2rem;
}

.logo-text strong {
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

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

.nav-link {
    position: relative;
    font-weight: 500;
    color: var(--dark);
    padding: 0.5rem 0;
}

.nav-link:hover,
.nav-link.active {
    color: var(--primary);
}

.nav-link.active::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    height: 2px;
    background: var(--gradient-primary);
}

.search-btn {
    padding: 0.75rem 1.5rem;
    background: var(--gradient-primary);
    color: white;
    border: none;
    border-radius: 50px;
    cursor: pointer;
    font-weight: 600;
    transition: var(--transition);
}

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

/* ========================================
   Hero Section
   ======================================== */

.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding: 8rem 2rem 4rem;
    overflow: hidden;
}

.hero-bg {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(135deg, #667eea15 0%, #764ba215 100%);
    z-index: -1;
}

.hero-content {
    max-width: 900px;
    text-align: center;
    margin: 0 auto;
}

.hero-title {
    font-size: clamp(2.5rem, 5vw, 4rem);
    margin-bottom: 1.5rem;
    animation: fadeInUp 0.8s ease-out;
}

.gradient-text {
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: 1.25rem;
    color: var(--gray);
    margin-bottom: 3rem;
    animation: fadeInUp 0.8s ease-out 0.2s both;
}

.hero-stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 2rem;
    margin-bottom: 3rem;
    animation: fadeInUp 0.8s ease-out 0.4s both;
}

.stat-item {
    padding: 1.5rem;
    background: white;
    border-radius: 1rem;
    box-shadow: var(--shadow-md);
}

.stat-number {
    font-size: 2.5rem;
    font-weight: 800;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.stat-label {
    color: var(--gray);
    font-size: 0.9rem;
    margin-top: 0.5rem;
}

.hero-cta {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
    animation: fadeInUp 0.8s ease-out 0.6s both;
}

/* ========================================
   Buttons
   ======================================== */

.btn {
    display: inline-block;
    padding: 1rem 2rem;
    border-radius: 50px;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    border: none;
    font-size: 1rem;
}

.btn-primary {
    background: var(--gradient-primary);
    color: white;
    box-shadow: var(--shadow-md);
}

.btn-primary:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-xl);
}

.btn-secondary {
    background: white;
    color: var(--primary);
    border: 2px solid var(--primary);
}

.btn-secondary:hover {
    background: var(--primary);
    color: white;
}

/* ========================================
   Sections
   ======================================== */

.section-header {
    text-align: center;
    margin-bottom: 4rem;
}

.section-title {
    font-size: clamp(2rem, 4vw, 3rem);
    margin-bottom: 1rem;
}

.section-subtitle {
    font-size: 1.1rem;
    color: var(--gray);
}

/* ========================================
   Categories
   ======================================== */

.categories-section {
    padding: var(--section-padding);
    background: var(--gray-lighter);
}

.categories-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.category-card {
    background: white;
    padding: 2rem;
    border-radius: 1rem;
    box-shadow: var(--shadow-md);
    transition: var(--transition);
    cursor: pointer;
    position: relative;
    overflow: hidden;
}

.category-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 4px;
    background: var(--gradient-primary);
    transform: scaleX(0);
    transition: var(--transition);
}

.category-card:hover::before {
    transform: scaleX(1);
}

.category-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-xl);
}

.category-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.category-name {
    font-size: 1.5rem;
    margin-bottom: 0.5rem;
}

.category-desc {
    color: var(--gray);
    margin-bottom: 1rem;
}

.category-count {
    display: inline-block;
    padding: 0.5rem 1rem;
    background: var(--gradient-primary);
    color: white;
    border-radius: 50px;
    font-size: 0.9rem;
    font-weight: 600;
}

/* ========================================
   Publications
   ======================================== */

.publications-section {
    padding: var(--section-padding);
}

.filter-tabs {
    display: flex;
    gap: 1rem;
    justify-content: center;
    margin-bottom: 3rem;
    flex-wrap: wrap;
}

.tab-btn {
    padding: 0.75rem 1.5rem;
    background: white;
    border: 2px solid var(--gray-light);
    border-radius: 50px;
    cursor: pointer;
    transition: var(--transition);
    font-weight: 600;
}

.tab-btn.active,
.tab-btn:hover {
    background: var(--gradient-primary);
    color: white;
    border-color: transparent;
}

.publications-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
    gap: 2rem;
}

.publication-card {
    background: white;
    border-radius: 1rem;
    box-shadow: var(--shadow-md);
    overflow: hidden;
    transition: var(--transition);
    display: flex;
    flex-direction: column;
}

.publication-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-xl);
}

.pub-header {
    padding: 1.5rem;
    background: var(--gradient-primary);
    color: white;
}

.pub-category {
    font-size: 0.85rem;
    opacity: 0.9;
    margin-bottom: 0.5rem;
}

.pub-title {
    font-size: 1.1rem;
    line-height: 1.4;
}

.pub-body {
    padding: 1.5rem;
    flex: 1;
}

.pub-authors {
    font-size: 0.9rem;
    color: var(--gray);
    margin-bottom: 1rem;
}

.pub-summary {
    color: var(--dark);
    line-height: 1.6;
    margin-bottom: 1rem;
}

.pub-footer {
    padding: 1rem 1.5rem;
    background: var(--gray-lighter);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.pub-date {
    font-size: 0.85rem;
    color: var(--gray);
}

.pub-link {
    padding: 0.5rem 1rem;
    background: var(--primary);
    color: white;
    border-radius: 50px;
    font-size: 0.85rem;
    font-weight: 600;
}

.pub-link:hover {
    background: var(--primary-dark);
}

.load-more-container {
    text-align: center;
    margin-top: 3rem;
}

/* ========================================
   About Section
   ======================================== */

.about-section {
    padding: var(--section-padding);
    background: var(--gray-lighter);
}

.about-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
}

.about-text {
    font-size: 1.1rem;
    line-height: 1.8;
    margin-bottom: 2rem;
}

.feature-list {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.feature-item {
    display: flex;
    gap: 1rem;
    align-items: flex-start;
}

.feature-icon {
    font-size: 2rem;
    flex-shrink: 0;
}

.feature-item h4 {
    margin-bottom: 0.25rem;
}

.feature-item p {
    color: var(--gray);
    font-size: 0.95rem;
}

.stats-card {
    background: white;
    padding: 2rem;
    border-radius: 1rem;
    box-shadow: var(--shadow-lg);
}

.stats-card h3 {
    margin-bottom: 1.5rem;
    color: var(--dark);
}

.mini-stat {
    display: flex;
    justify-content: space-between;
    padding: 1rem 0;
    border-bottom: 1px solid var(--gray-light);
}

.mini-stat:last-child {
    border-bottom: none;
}

.mini-stat-label {
    color: var(--gray);
}

.mini-stat-value {
    font-weight: 700;
    color: var(--primary);
}

/* ========================================
   Search Overlay
   ======================================== */

.search-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.9);
    z-index: 2000;
    display: none;
    align-items: flex-start;
    padding: 4rem 2rem;
}

.search-overlay.active {
    display: flex;
}

.search-container {
    max-width: 800px;
    width: 100%;
    margin: 0 auto;
    position: relative;
}

#searchInput {
    width: 100%;
    padding: 1.5rem 4rem 1.5rem 2rem;
    font-size: 1.5rem;
    border: none;
    border-radius: 1rem;
    box-shadow: var(--shadow-xl);
}

.close-search {
    position: absolute;
    right: 1rem;
    top: 1rem;
    background: transparent;
    border: none;
    font-size: 2rem;
    cursor: pointer;
    color: var(--gray);
}

.search-results {
    margin-top: 2rem;
    background: white;
    border-radius: 1rem;
    padding: 1rem;
    max-height: 60vh;
    overflow-y: auto;
}

/* ========================================
   Footer
   ======================================== */

.footer {
    background: var(--dark);
    color: white;
    padding: 3rem 2rem 1rem;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 3rem;
    margin-bottom: 2rem;
}

.footer-brand {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

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

.footer-links h4 {
    margin-bottom: 1rem;
    font-size: 1.1rem;
}

.footer-links ul {
    list-style: none;
}

.footer-links li {
    margin-bottom: 0.5rem;
}

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

.footer-links a:hover {
    color: white;
}

.footer-bottom {
    border-top: 1px solid var(--dark-light);
    padding-top: 2rem;
    text-align: center;
}

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

.footer-note {
    margin-top: 0.5rem;
    font-size: 0.8rem;
    opacity: 0.7;
}

/* ========================================
   Animations
   ======================================== */

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* ========================================
   Responsive
   ======================================== */

@media (max-width: 768px) {
    .nav-menu {
        display: none;
    }

    .hero {
        padding: 6rem 1rem 3rem;
    }

    .hero-stats {
        grid-template-columns: 1fr;
    }

    .categories-grid,
    .publications-grid {
        grid-template-columns: 1fr;
    }

    .about-grid {
        grid-template-columns: 1fr;
    }

    .footer-content {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    .hero-title {
        font-size: 2rem;
    }

    .section-title {
        font-size: 1.75rem;
    }
}