:root {
    --primary: #2563eb;
    --success: #16a34a;
    --bg: #f8fafc;
    --card: #ffffff;
    --text: #1e293b;
    --border: #e2e8f0;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    background-color: var(--bg);
    color: var(--text);
    margin: 0;
    padding: 20px;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
}

.container {
    background: var(--card);
    max-width: 550px;
    width: 100%;
    padding: 30px;
    border-radius: 16px;
    box-shadow: 0 10px 25px -5px rgba(0, 0, 0, 0.05);
}

header {
    text-align: center;
    margin-bottom: 25px;
}

header h1 { margin: 0 0 5px 0; font-size: 1.8rem; color: #0f172a; }
header p { margin: 0; color: #64748b; font-size: 0.95rem; }

.drop-zone {
    border: 2px dashed var(--primary);
    border-radius: 12px;
    padding: 40px 20px;
    text-align: center;
    background: #eff6ff;
    cursor: pointer;
    transition: all 0.2s ease;
}

.drop-zone:hover { background: #dbeafe; }
.drop-zone-prompt p { margin: 10px 0 0 0; font-size: 1rem; color: #475569; }
.drop-zone-prompt span { color: var(--primary); font-weight: 600; }

.workspace {
    margin-top: 25px;
    border-top: 1px solid var(--border);
    padding-top: 25px;
}

.preview-box {
    display: flex;
    align-items: center;
    gap: 15px;
    background: var(--bg);
    padding: 12px;
    border-radius: 8px;
    margin-bottom: 20px;
}

#imagePreview {
    width: 80px;
    height: 80px;
    object-fit: cover;
    border-radius: 6px;
    background: #cbd5e1;
}

.file-info p { margin: 3px 0; font-size: 0.9rem; }
.file-info p:first-child { font-weight: 600; color: #334155;}

.control-group {
    margin-bottom: 20px;
}

label {
    display: block;
    font-size: 0.9rem;
    font-weight: 500;
    margin-bottom: 8px;
    display: flex;
    justify-content: space-between;
}

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

.btn-primary, .btn-success {
    display: block;
    width: 100%;
    text-align: center;
    padding: 12px;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    text-decoration: none;
    box-sizing: border-box;
}

.btn-primary { background: var(--primary); color: white; }
.btn-primary:hover { background: #1d4ed8; }

.result-box {
    margin-top: 25px;
    background: #f0fdf4;
    border: 1px solid #bbf7d0;
    padding: 20px;
    border-radius: 12px;
    text-align: center;
}
.result-box h3 { margin: 0 0 5px 0; color: #166534; font-size: 1.1rem; }
.result-box p { margin: 0 0 15px 0; color: #15803d; font-size: 0.95rem; }
.btn-success { background: var(--success); color: white; }
.btn-success:hover { background: #15803d; }