:root {
    --bg-gradient: linear-gradient(135deg, #0f172a, #1e1b4b);
    --card-bg: rgba(255, 255, 255, 0.05);
    --card-border: rgba(255, 255, 255, 0.1);
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --accent-color: #6366f1;
    --accent-hover: #4f46e5;
    --success-color: #10b981;
    --success-hover: #059669;
    --danger-color: #ef4444;
}

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

body {
    font-family: 'Inter', sans-serif;
    background: var(--bg-gradient);
    min-height: 100vh;
    color: var(--text-primary);
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 2rem;
}

.app-container {
    background: var(--card-bg);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid var(--card-border);
    border-radius: 24px;
    padding: 3rem;
    width: 100%;
    max-width: 900px;
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
    position: relative;
    overflow: hidden;
}

header {
    text-align: center;
    margin-bottom: 3rem;
}

header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    background: linear-gradient(to right, #818cf8, #a78bfa);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

header p {
    color: var(--text-secondary);
    font-size: 1.1rem;
}

/* Drop Zone */
.drop-zone {
    border: 2px dashed var(--card-border);
    border-radius: 16px;
    padding: 4rem 2rem;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s ease;
    background: rgba(255, 255, 255, 0.02);
}

.drop-zone:hover {
    border-color: rgba(99, 102, 241, 0.5);
    background: rgba(255, 255, 255, 0.04);
}

.drop-zone.dragover {
    border-color: var(--accent-color);
    background: rgba(99, 102, 241, 0.1);
}

.drop-zone-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1rem;
}

.upload-icon {
    width: 64px;
    height: 64px;
    color: var(--accent-color);
    margin-bottom: 1rem;
}

.drop-zone p {
    font-size: 1.25rem;
    color: var(--text-primary);
}

.or-divider {
    color: var(--text-secondary);
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 1px;
}

button {
    font-family: 'Inter', sans-serif;
    border: none;
    padding: 0.75rem 1.5rem;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
}

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

.btn-primary:hover {
    background: var(--accent-hover);
    transform: translateY(-2px);
}

.btn-success {
    background: var(--success-color);
    color: white;
}

.btn-success:hover {
    background: var(--success-hover);
    transform: translateY(-2px);
}

.btn-secondary {
    background: transparent;
    border: 1px solid var(--card-border);
    color: var(--text-primary);
}

.btn-secondary:hover {
    background: rgba(255, 255, 255, 0.1);
}

/* Results */
.hidden {
    display: none !important;
}

.comparison-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
    margin-bottom: 2rem;
}

@media (max-width: 768px) {
    .comparison-grid {
        grid-template-columns: 1fr;
    }
}

.image-card {
    background: rgba(0, 0, 0, 0.2);
    border-radius: 16px;
    padding: 1.5rem;
    display: flex;
    flex-direction: column;
    gap: 1rem;
    border: 1px solid var(--card-border);
}

.image-card h3 {
    text-align: center;
    font-size: 1.1rem;
    font-weight: 500;
}

.image-wrapper {
    width: 100%;
    aspect-ratio: 4/3;
    border-radius: 8px;
    overflow: hidden;
    background: rgba(0, 0, 0, 0.3);
    display: flex;
    align-items: center;
    justify-content: center;
}

.image-wrapper img {
    max-width: 100%;
    max-height: 100%;
    object-fit: contain;
}

.stats {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.75rem;
    background: rgba(255, 255, 255, 0.05);
    border-radius: 8px;
}

.stats .value {
    font-weight: 600;
    font-family: monospace;
    font-size: 1.1rem;
}

.compressed .stats .value {
    color: var(--success-color);
}
.compressed .stats .value.error {
    color: var(--danger-color);
}

.actions {
    display: flex;
    justify-content: center;
    gap: 1rem;
}

/* Loading Overlay */
.loading-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(15, 23, 42, 0.8);
    backdrop-filter: blur(8px);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    gap: 1rem;
    z-index: 10;
    border-radius: 24px;
}

.spinner {
    width: 50px;
    height: 50px;
    border: 4px solid var(--card-border);
    border-top-color: var(--accent-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

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

/* Footer Credits */
footer {
    margin-top: 3rem;
    text-align: center;
    border-top: 1px solid var(--card-border);
    padding-top: 1.5rem;
}

.credits p {
    color: var(--text-secondary);
    font-size: 0.95rem;
    letter-spacing: 0.8px;
}

.credits strong {
    background: linear-gradient(to right, #818cf8, #a78bfa);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    font-weight: 700;
    margin-left: 4px;
}