body {
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen', 'Ubuntu', 'Cantarell', sans-serif;
}

main {
    flex: 1;
}

/* Card Enhancements */
.card {
    box-shadow: 0 4px 12px rgba(0,0,0,0.1);
    margin-bottom: 24px;
    border: none;
    border-radius: 12px;
    overflow: hidden;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.card:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 24px rgba(0,0,0,0.15);
}

.card-header {
    font-weight: 600;
    padding: 16px 20px;
    border-bottom: 2px solid rgba(255,255,255,0.2);
    letter-spacing: 0.5px;
}

/* Button Enhancements */
.btn {
    transition: all 0.3s ease;
    border-radius: 8px;
    font-weight: 500;
    padding: 10px 24px;
    letter-spacing: 0.5px;
}

.btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 16px rgba(0,0,0,0.2);
}

.btn-primary {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    border: none;
}

.btn-primary:hover {
    background: linear-gradient(135deg, #764ba2 0%, #667eea 100%);
}

.btn-success {
    background: linear-gradient(135deg, #28a745 0%, #20c997 100%);
    border: none;
}

.btn-secondary {
    background: linear-gradient(135deg, #6c757d 0%, #495057 100%);
    border: none;
}

/* Animations */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

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

.fade-in {
    animation: fadeIn 0.6s ease-out;
}

.card {
    animation: fadeIn 0.5s ease-out;
}

/* Badge Enhancements */
.badge {
    padding: 6px 12px;
    border-radius: 20px;
    font-weight: 600;
    letter-spacing: 0.5px;
}

/* Alert Enhancements */
.alert {
    border-radius: 10px;
    border: none;
    box-shadow: 0 2px 8px rgba(0,0,0,0.1);
    animation: slideIn 0.4s ease-out;
}

/* Navbar Enhancement */
.navbar {
    box-shadow: 0 2px 8px rgba(0,0,0,0.15);
}

/* Footer Enhancement */
footer {
    box-shadow: 0 -2px 8px rgba(0,0,0,0.1);
    background: linear-gradient(135deg, #f8f9fa 0%, #e9ecef 100%) !important;
}

/* Textarea Enhancement */
textarea.form-control {
    border-radius: 8px;
    border: 2px solid #e1e4e8;
    transition: border-color 0.3s ease, box-shadow 0.3s ease;
}

textarea.form-control:focus {
    border-color: #667eea;
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

/* Loading Overlay */
.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.7);
    backdrop-filter: blur(4px);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    z-index: 9999;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s ease, visibility 0.3s ease;
}

.loading-overlay.active {
    opacity: 1;
    visibility: visible;
}

.loading-content {
    text-align: center;
    color: white;
}

.loading-spinner {
    width: 60px;
    height: 60px;
    border: 4px solid rgba(255, 255, 255, 0.3);
    border-top: 4px solid #667eea;
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin: 0 auto 24px;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

.loading-title {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 12px;
    animation: pulse 2s ease-in-out infinite;
}

.loading-subtitle {
    font-size: 1rem;
    opacity: 0.8;
    max-width: 300px;
    line-height: 1.5;
}

.loading-dots {
    display: inline-flex;
    gap: 4px;
    margin-left: 4px;
}

.loading-dots span {
    width: 6px;
    height: 6px;
    background: white;
    border-radius: 50%;
    animation: bounce 1.4s ease-in-out infinite;
}

.loading-dots span:nth-child(1) { animation-delay: 0s; }
.loading-dots span:nth-child(2) { animation-delay: 0.2s; }
.loading-dots span:nth-child(3) { animation-delay: 0.4s; }

@keyframes bounce {
    0%, 80%, 100% {
        transform: translateY(0);
        opacity: 0.4;
    }
    40% {
        transform: translateY(-8px);
        opacity: 1;
    }
}

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.7; }
}

/* Submit button loading state */
.btn-loading {
    position: relative;
    pointer-events: none;
    opacity: 0.8;
}

.btn-loading .btn-text {
    visibility: hidden;
}

.btn-loading::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 20px;
    height: 20px;
    margin: -10px 0 0 -10px;
    border: 2px solid rgba(255, 255, 255, 0.3);
    border-top-color: white;
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

/* Responsive Adjustments */
@media (max-width: 768px) {
    .diff-table {
        font-size: 11px;
    }

    .line-number {
        width: 35px;
        font-size: 10px;
    }

    .card {
        border-radius: 8px;
        margin-bottom: 16px;
    }

    .btn {
        padding: 8px 16px;
        font-size: 14px;
    }
}