:root {
    --bg-color: #0f172a;
    --panel-bg: #1e293b;
    --primary: #3b82f6;
    --primary-hover: #2563eb;
    --text-main: #f8fafc;
    --text-muted: #94a3b8;
    --success: #10b981;
    --border-color: #334155;
    --glass-bg: rgba(30, 41, 59, 0.7);
    --glass-border: rgba(255, 255, 255, 0.1);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Inter', sans-serif;
}

body {
    background-color: var(--bg-color);
    color: var(--text-main);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    background-image: 
        radial-gradient(circle at 15% 50%, rgba(59, 130, 246, 0.15) 0%, transparent 50%),
        radial-gradient(circle at 85% 30%, rgba(16, 185, 129, 0.15) 0%, transparent 50%);
}

.app-container {
    width: 100%;
    max-width: 1000px;
    margin: 2rem;
    padding: 2.5rem;
    background: var(--glass-bg);
    backdrop-filter: blur(12px);
    border: 1px solid var(--glass-border);
    border-radius: 24px;
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
}

header {
    text-align: center;
    margin-bottom: 2.5rem;
}

header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    background: linear-gradient(135deg, #60a5fa, #a78bfa);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

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

.upload-section {
    border: 2px dashed var(--border-color);
    border-radius: 16px;
    padding: 4rem 2rem;
    text-align: center;
    transition: all 0.3s ease;
    background: rgba(15, 23, 42, 0.4);
}

.upload-section.dragover {
    border-color: var(--primary);
    background: rgba(59, 130, 246, 0.1);
    transform: scale(1.02);
}

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

.upload-icon {
    font-size: 4rem;
    color: var(--primary);
    margin-bottom: 1rem;
}

.upload-content h2 {
    font-size: 1.5rem;
    font-weight: 600;
}

.upload-content p {
    color: var(--text-muted);
}

.btn-primary, .btn-secondary {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.75rem 1.5rem;
    border-radius: 8px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
    border: none;
    font-size: 1rem;
}

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

.btn-primary:hover {
    background-color: var(--primary-hover);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(59, 130, 246, 0.3);
}

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

.btn-secondary:hover {
    background-color: rgba(255, 255, 255, 0.05);
}

.hidden {
    display: none !important;
}

.workspace-section {
    display: flex;
    flex-direction: column;
    gap: 2rem;
    animation: fadeIn 0.5s ease;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

.controls-panel {
    display: flex;
    flex-wrap: wrap;
    gap: 1.5rem;
    align-items: flex-end;
    background: var(--panel-bg);
    padding: 1.5rem;
    border-radius: 12px;
    border: 1px solid var(--border-color);
}

.control-group {
    flex: 1;
    min-width: 200px;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.control-group label {
    font-weight: 500;
    color: var(--text-muted);
    display: flex;
    justify-content: space-between;
}

#qualityValue {
    color: var(--primary);
    font-weight: 700;
}

input[type="range"] {
    width: 100%;
    accent-color: var(--primary);
    cursor: pointer;
}

select {
    padding: 0.5rem;
    border-radius: 6px;
    background: var(--bg-color);
    color: var(--text-main);
    border: 1px solid var(--border-color);
    outline: none;
    cursor: pointer;
}

.preview-panel {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
}

@media (max-width: 768px) {
    .preview-panel {
        grid-template-columns: 1fr;
    }
    .app-container {
        padding: 1.5rem;
        margin: 1rem;
    }
}

.preview-box {
    background: var(--panel-bg);
    border-radius: 12px;
    padding: 1.5rem;
    border: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.preview-box.compressed {
    border-color: rgba(16, 185, 129, 0.3);
    box-shadow: 0 0 20px rgba(16, 185, 129, 0.05);
}

.preview-box h3 {
    text-align: center;
    color: var(--text-muted);
}

.image-wrapper {
    height: 300px;
    border-radius: 8px;
    overflow: hidden;
    background: repeating-conic-gradient(#334155 0% 25%, transparent 0% 50%) 50% / 20px 20px;
    background-color: #1e293b;
    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-top: 0.5rem;
}

.size-badge {
    background: rgba(255, 255, 255, 0.1);
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    font-size: 0.875rem;
    font-weight: 500;
}

.size-badge.highlight {
    background: rgba(16, 185, 129, 0.2);
    color: var(--success);
}

.savings-badge {
    color: var(--success);
    font-weight: 600;
    font-size: 0.875rem;
}

.download-btn {
    width: 100%;
    margin-top: 0.5rem;
    background-color: var(--success);
}

.download-btn:hover {
    background-color: #059669;
    box-shadow: 0 4px 12px rgba(16, 185, 129, 0.3);
}