:root {
    --primary-color: #ff0000;
    --primary-hover: #cc0000;
    --secondary-color: #282828;
    --light-bg: #f8f9fa;
    --dark-text: #212529;
    --border-radius: 12px;
    --box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

* {
    box-sizing: border-box;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    margin: 0;
    padding: 20px 0;
}

.container {
    max-width: 1200px;
}

/* Hero Section */
.hero-section {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-radius: var(--border-radius);
    padding: 3rem 2rem;
    margin-bottom: 2rem;
    box-shadow: var(--box-shadow);
}

.hero-icon {
    font-size: 4rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
    display: block;
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0% { transform: scale(1); }
    50% { transform: scale(1.05); }
    100% { transform: scale(1); }
}

.display-4 {
    background: linear-gradient(45deg, var(--primary-color), var(--primary-hover));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* Main Card */
.main-card {
    border-radius: var(--border-radius);
    backdrop-filter: blur(10px);
    background: rgba(255, 255, 255, 0.95);
    transition: var(--transition);
}

.main-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.15);
}

/* Form Styling */
.input-group-lg .form-control {
    border-radius: 0;
    padding: 1rem 1.5rem;
    font-size: 1.1rem;
    transition: var(--transition);
}

.input-group-lg .form-control:focus {
    box-shadow: 0 0 0 0.25rem rgba(255, 0, 0, 0.25);
    border-color: var(--primary-color);
}

.input-group-text {
    border-radius: var(--border-radius) 0 0 var(--border-radius);
    background: var(--primary-color) !important;
    border: none;
    padding: 1rem 1.5rem;
}

.btn-primary {
    background: var(--primary-color);
    border: none;
    border-radius: 0 var(--border-radius) var(--border-radius) 0;
    transition: var(--transition);
    font-weight: 600;
}

.btn-primary:hover {
    background: var(--primary-hover);
    transform: translateY(-1px);
}

/* Alert Styling */
.alert {
    border: none;
    border-radius: var(--border-radius);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
    animation: slideIn 0.5s ease-out;
}

@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateY(-20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Thumbnail Cards */
.thumbnail-card {
    border-radius: var(--border-radius);
    transition: var(--transition);
    overflow: hidden;
    background: white;
}

.thumbnail-card:hover {
    transform: translateY(-8px);
    box-shadow: 0 15px 35px rgba(0, 0, 0, 0.15);
}

.thumbnail-container {
    position: relative;
    overflow: hidden;
    border-radius: 8px;
    background: #f8f9fa;
    min-height: 150px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.thumbnail-image {
    max-width: 100%;
    height: auto;
    border-radius: 8px;
    transition: var(--transition);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
}

.thumbnail-image:hover {
    transform: scale(1.05);
}

.card-header {
    background: linear-gradient(45deg, #f8f9fa, #e9ecef) !important;
    border-bottom: 2px solid #dee2e6;
}

/* Instructions Section */
.instruction-step {
    padding: 1rem;
}

.step-number {
    width: 50px;
    height: 50px;
    background: linear-gradient(45deg, var(--primary-color), var(--primary-hover));
    color: white;
    border-radius: 50%;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-weight: bold;
    font-size: 1.2rem;
    margin-bottom: 1rem;
    box-shadow: 0 5px 15px rgba(255, 0, 0, 0.3);
}

/* Responsive Design */
@media (max-width: 768px) {
    .hero-section {
        padding: 2rem 1rem;
    }
    
    .hero-icon {
        font-size: 3rem;
    }
    
    .display-4 {
        font-size: 2.5rem;
    }
    
    .main-card .card-body {
        padding: 2rem 1.5rem;
    }
    
    .input-group-lg .form-control,
    .input-group-lg .btn {
        font-size: 1rem;
        padding: 0.875rem 1.25rem;
    }
    
    .thumbnail-card {
        margin-bottom: 1rem;
    }
}

@media (max-width: 576px) {
    body {
        padding: 10px 0;
    }
    
    .input-group-lg {
        flex-direction: column;
    }
    
    .input-group-lg .input-group-text,
    .input-group-lg .form-control,
    .input-group-lg .btn {
        border-radius: var(--border-radius);
        margin-bottom: 0.5rem;
    }
    
    .input-group-lg .btn {
        margin-bottom: 0;
    }
}

/* Loading Animation */
.spinner-border-sm {
    width: 1rem;
    height: 1rem;
}

/* Smooth Scrolling */
html {
    scroll-behavior: smooth;
}

/* Custom Scrollbar */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: #f1f1f1;
}

::-webkit-scrollbar-thumb {
    background: var(--primary-color);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--primary-hover);
}

/* Focus Styles for Accessibility */
.btn:focus,
.form-control:focus {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

/* Print Styles */
@media print {
    body {
        background: white;
    }
    
    .hero-section,
    .main-card,
    .thumbnail-card {
        box-shadow: none;
        border: 1px solid #ddd;
    }
}