/* Modern CSS Styles for Medical AI Website */

:root {
    /* Color Palette - Medical/Tech Theme */
    --primary-color: #2563eb;
    --primary-hover: #1d4ed8;
    --secondary-color: #0f172a;
    --accent-color: #06b6d4;
    --background: linear-gradient(135deg, #f0f9ff 0%, #e0f2fe 100%);
    --card-background: rgba(255, 255, 255, 0.95);
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --border-color: #e2e8f0;
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 20px 40px rgba(0, 0, 0, 0.15);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen', 'Ubuntu', 'Helvetica Neue', sans-serif;
    background: var(--background);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Modern Navigation Bar */
.navbar {
    background: var(--secondary-color);
    backdrop-filter: blur(10px);
    box-shadow: var(--shadow-md);
    padding: 0;
    position: sticky;
    top: 0;
    z-index: 1000;
    width: 100%;
}

.navbar-content {
    max-width: 1400px;
    margin: 0 auto;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 0 20px;
}

.navbar a {
    color: white;
    text-decoration: none;
    padding: 18px 24px;
    font-size: 0.95rem;
    font-weight: 500;
    letter-spacing: 0.3px;
    transition: all 0.3s ease;
    position: relative;
}

.navbar a::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    width: 0;
    height: 3px;
    background: var(--accent-color);
    transform: translateX(-50%);
    transition: width 0.3s ease;
}

.navbar a:hover::after {
    width: 80%;
}

.navbar .home-button {
    background: linear-gradient(135deg, var(--primary-color), var(--primary-hover));
    border-radius: 8px;
    margin-right: 30px;
    font-weight: 600;
}

.navbar .home-button:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(37, 99, 235, 0.3);
}

/* Dropdown Improvements */
.dropdown {
    position: relative;
    display: inline-block;
}

.dropdown-content {
    display: none;
    position: absolute;
    background: white;
    min-width: 200px;
    box-shadow: var(--shadow-xl);
    border-radius: 12px;
    overflow: hidden;
    top: 100%;
    margin-top: 5px;
    opacity: 0;
    transform: translateY(-10px);
    transition: all 0.3s ease;
}

.dropdown:hover .dropdown-content {
    display: block;
    opacity: 1;
    transform: translateY(0);
}

.dropdown-content a {
    color: var(--text-primary);
    padding: 14px 20px;
    text-decoration: none;
    display: block;
    transition: all 0.2s ease;
    font-weight: 400;
}

.dropdown-content a:hover {
    background: linear-gradient(90deg, var(--accent-color), var(--primary-color));
    color: white;
    padding-left: 28px;
}

/* Main Container */
.main-container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 40px 20px;
    width: 100%;
    flex: 1;
}

/* Hero Section */
.introduction {
    text-align: center;
    margin-bottom: 60px;
    animation: fadeInUp 0.8s ease;
}

.introduction h1 {
    font-size: 3rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 20px;
    letter-spacing: -1px;
}

.introduction p {
    font-size: 1.25rem;
    color: var(--text-secondary);
    max-width: 900px;
    margin: 0 auto;
    line-height: 1.8;
}

/* Modern Card Grid */
.image-grid {
    display: grid;
    gap: 30px;
    margin-bottom: 40px;
}

.image-grid > div {
    background: var(--card-background);
    border-radius: 16px;
    overflow: hidden;
    box-shadow: var(--shadow-md);
    transition: all 0.3s ease;
    position: relative;
}

.image-grid > div:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-xl);
}

.image-grid img {
    width: 100%;
    height: 250px;
    object-fit: cover;
    border-bottom: 1px solid var(--border-color);
}

/* Modern Buttons */
button, .btn {
    padding: 14px 28px;
    font-size: 1rem;
    font-weight: 600;
    background: linear-gradient(135deg, var(--primary-color), var(--primary-hover));
    color: white;
    border: none;
    border-radius: 10px;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: var(--shadow-md);
    letter-spacing: 0.5px;
    margin: 15px 10px;
    display: inline-block;
    text-decoration: none;
}

button:hover, .btn:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 20px rgba(37, 99, 235, 0.4);
}

button:active, .btn:active {
    transform: translateY(-1px);
}

button:disabled {
    background: linear-gradient(135deg, #cbd5e1, #94a3b8);
    cursor: not-allowed;
    transform: none;
}

/* Canvas Styling */
canvas {
    border: 2px solid var(--border-color);
    border-radius: 12px;
    box-shadow: var(--shadow-md);
    background: white;
    margin: 20px auto;
    display: block;
}

/* Instructions Section */
.instructions {
    background: var(--card-background);
    border-radius: 16px;
    padding: 30px;
    margin: 30px auto;
    max-width: 900px;
    box-shadow: var(--shadow-md);
    border-left: 4px solid var(--accent-color);
}

.instructions h2 {
    color: var(--primary-color);
    margin-bottom: 15px;
    font-size: 1.5rem;
}

/* Main Image */
.main-image {
    width: 80%;
    max-width: 1000px;
    margin: 40px auto;
    text-align: center;
}

.main-image img {
    width: 100%;
    height: auto;
    border-radius: 16px;
    box-shadow: var(--shadow-xl);
}

/* Footer */
footer {
    background: var(--secondary-color);
    color: white;
    text-align: center;
    padding: 30px 20px;
    margin-top: auto;
    font-size: 0.9rem;
}

/* Loading Spinner */
.loading {
    display: inline-block;
    width: 20px;
    height: 20px;
    border: 3px solid rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    border-top-color: white;
    animation: spin 1s ease-in-out infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

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

/* Responsive Design */
@media (max-width: 768px) {
    .introduction h1 {
        font-size: 2rem;
    }
    
    .introduction p {
        font-size: 1.1rem;
    }
    
    .image-grid {
        grid-template-columns: 1fr !important;
    }
    
    .navbar-content {
        flex-wrap: wrap;
        justify-content: center;
    }
    
    .navbar .home-button {
        margin-right: 10px;
        margin-bottom: 5px;
    }
    
    .main-image {
        width: 95%;
    }
    
    button, .btn {
        padding: 12px 24px;
        font-size: 0.95rem;
    }
}

@media (max-width: 480px) {
    .navbar a {
        padding: 12px 16px;
        font-size: 0.9rem;
    }
    
    .dropdown-content {
        min-width: 150px;
    }
}

/* Utility Classes */
.text-center { text-align: center; }
.mt-20 { margin-top: 20px; }
.mb-20 { margin-bottom: 20px; }
.fade-in { animation: fadeInUp 0.8s ease; }