:root {
    --bg-color: #0f172a;
    --text-main: #f8fafc;
    --text-muted: #94a3b8;
    --primary-color: #3b82f6;
    --primary-hover: #2563eb;
    --danger-color: #ef4444;
    --danger-hover: #dc2626;
    --success-color: #10b981;
    --glass-bg: rgba(30, 41, 59, 0.7);
    --glass-border: rgba(255, 255, 255, 0.1);
    --gradient-1: #3b82f6;
    --gradient-2: #8b5cf6;
    --font-family: 'Inter', system-ui, -apple-system, sans-serif;
    --border-radius: 16px;
}

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

body {
    background-color: var(--bg-color);
    background-image: radial-gradient(circle at 15% 50%, rgba(59, 130, 246, 0.15), transparent 25%),
                      radial-gradient(circle at 85% 30%, rgba(139, 92, 246, 0.15), transparent 25%);
    background-attachment: fixed;
    color: var(--text-main);
    font-family: var(--font-family);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.container { width: 100%; max-width: 900px; margin: 0 auto; padding: 0 20px; }
.mt-3 { margin-top: 1rem; }
.mt-4 { margin-top: 1.5rem; }
.ml-3 { margin-left: 1rem; }
.text-center { text-align: center; }
.text-muted { color: var(--text-muted); }
.hidden { display: none !important; }

/* HERO & INSTALL BUTTON */
.hero { padding: 40px 20px; }
.hero-container {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 20px;
    text-align: center;
}
.hero h1 { font-size: 2.5rem; font-weight: 700; margin-bottom: 10px; }
.text-gradient {
    background: linear-gradient(135deg, var(--gradient-1), var(--gradient-2));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}
.hero p { color: var(--text-muted); font-size: 1.1rem; max-width: 600px; }
.install-btn {
    display: flex;
    align-items: center;
    gap: 8px;
    background: rgba(255,255,255,0.05);
}

/* GLASS PANEL */
.glass-panel {
    background: var(--glass-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid var(--glass-border);
    border-radius: var(--border-radius);
    padding: 30px;
    margin-bottom: 30px;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.2);
    animation: fadeIn 0.4s ease-out forwards;
}
@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

/* BUTTONS */
button {
    font-family: var(--font-family);
    cursor: pointer;
    border: none;
    border-radius: 8px;
    font-weight: 600;
    font-size: 1rem;
    padding: 12px 24px;
    transition: all 0.2s ease;
}
button:disabled { opacity: 0.6; cursor: not-allowed; }
.btn-primary { background-color: var(--primary-color); color: white; }
.btn-primary:hover:not(:disabled) { background-color: var(--primary-hover); }
.btn-danger { background-color: var(--danger-color); color: white; padding: 8px 16px; font-size: 0.9rem; }
.btn-danger:hover:not(:disabled) { background-color: var(--danger-hover); }
.btn-gradient { background: linear-gradient(135deg, var(--gradient-1), var(--gradient-2)); color: white; width: 100%; }
.btn-gradient:hover:not(:disabled) { box-shadow: 0 4px 15px rgba(139, 92, 246, 0.4); transform: translateY(-2px); }
.btn-outline { background: transparent; border: 1px solid var(--text-muted); color: var(--text-main); }
.btn-outline:hover:not(:disabled) { background: rgba(255, 255, 255, 0.1); }

/* UPLOAD ZONE */
.drop-zone {
    border: 2px dashed var(--glass-border);
    border-radius: var(--border-radius);
    padding: 50px 20px;
    text-align: center;
    transition: all 0.3s ease;
    cursor: pointer;
}
.drop-zone.dragover { border-color: var(--primary-color); background: rgba(59, 130, 246, 0.1); }
.upload-icon { color: var(--text-muted); margin-bottom: 15px; }

/* CONTOH GAMBAR (SAMPLE GALLERY) */
.sample-gallery {
    display: flex;
    justify-content: center;
    gap: 15px;
    flex-wrap: wrap;
}
.sample-gallery img {
    width: 100px;
    height: 70px;
    object-fit: cover;
    border-radius: 8px;
    cursor: pointer;
    border: 2px solid transparent;
    transition: all 0.2s ease;
    opacity: 0.8;
}
.sample-gallery img:hover {
    opacity: 1;
    transform: scale(1.05);
    border-color: var(--primary-color);
}
.uploading-state { opacity: 0.5; pointer-events: none; }

/* PREVIEW SECTION */
.preview-layout { display: grid; grid-template-columns: 1fr 1fr; gap: 30px; }
.preview-image-container {
    position: relative; border-radius: 12px; overflow: hidden; background: #000;
    display: flex; align-items: center; justify-content: center; min-height: 250px;
}
.preview-image-container img { max-width: 100%; max-height: 350px; object-fit: contain; }
.remove-btn { position: absolute; top: 10px; right: 10px; z-index: 10; }
.file-details { list-style: none; margin-top: 10px; color: var(--text-muted); }
.file-details li { margin-bottom: 5px; }
.file-details strong { color: var(--text-main); }

/* RADIOS */
.radio-group { display: flex; flex-direction: column; gap: 15px; margin-top: 15px; }
.radio-card { position: relative; display: block; cursor: pointer; }
.radio-card input { position: absolute; opacity: 0; }
.card-content {
    display: flex; flex-direction: column; padding: 15px; border: 2px solid var(--glass-border);
    border-radius: 12px; transition: all 0.2s ease;
}
.card-content strong { font-size: 1.1rem; }
.card-content span { font-size: 0.85rem; color: var(--text-muted); }
.radio-card input:checked + .card-content { border-color: var(--primary-color); background: rgba(59, 130, 246, 0.1); }

/* SPINNER */
.spinner {
    width: 50px; height: 50px; border: 4px solid rgba(255,255,255,0.1);
    border-left-color: var(--primary-color); border-radius: 50%;
    animation: spin 1s linear infinite; margin: 0 auto;
}
@keyframes spin { 100% { transform: rotate(360deg); } }

/* ALERTS */
.alert {
    padding: 15px 20px; border-radius: 8px; margin-bottom: 20px; display: flex;
    justify-content: space-between; align-items: center;
    background: rgba(239, 68, 68, 0.1); border: 1px solid var(--danger-color); color: #fca5a5;
}
.alert.success { background: rgba(16, 185, 129, 0.1); border: 1px solid var(--success-color); color: #6ee7b7; }
.close-alert { background: transparent; color: inherit; border: none; font-size: 1.5rem; line-height: 1; padding: 0; }

/* SLIDER */
.comparison-container {
    position: relative; width: 100%; background: #000; border-radius: 12px; overflow: hidden;
    margin-top: 20px; user-select: none; min-height: 300px; display: flex;
}
.comparison-container img { position: absolute; top: 0; left: 0; width: 100%; height: 100%; object-fit: contain; pointer-events: none; }
.img-after { clip-path: polygon(var(--pos, 50%) 0, 100% 0, 100% 100%, var(--pos, 50%) 100%); }
.slider-handle {
    position: absolute; top: 0; bottom: 0; left: var(--pos, 50%); width: 4px;
    background: white; transform: translateX(-50%); cursor: ew-resize; z-index: 5;
}
.slider-button {
    position: absolute; top: 50%; left: 50%; transform: translate(-50%, -50%); width: 40px; height: 40px;
    background: white; border-radius: 50%; display: flex; justify-content: center; align-items: center;
    box-shadow: 0 0 10px rgba(0,0,0,0.5); color: var(--bg-color);
}
.slider-button svg { width: 16px; height: 16px; }
.label {
    position: absolute; top: 15px; padding: 4px 12px; background: rgba(0,0,0,0.6);
    backdrop-filter: blur(4px); color: white; border-radius: 20px; font-size: 0.8rem; font-weight: 600; z-index: 4;
}
.label-before { left: 15px; }
.label-after { right: 15px; }

/* RESULT STATS */
.result-stats { display: grid; grid-template-columns: repeat(3, 1fr); gap: 15px; }
.stat-box { background: rgba(255, 255, 255, 0.05); padding: 15px; border-radius: 8px; text-align: center; }
.stat-title { display: block; font-size: 0.85rem; color: var(--text-muted); margin-bottom: 5px; }
.stat-box strong { font-size: 1.2rem; color: var(--text-main); }

/* FOOTER */
footer { margin-top: auto; text-align: center; padding: 20px; color: var(--text-muted); font-size: 0.9rem; }
footer a { color: var(--primary-color); text-decoration: none; }

/* RESPONSIVE */
@media (max-width: 768px) {
    .preview-layout { grid-template-columns: 1fr; }
    .result-stats { grid-template-columns: 1fr; }
    .hero h1 { font-size: 2rem; }
    .comparison-container { height: 60vw; }
}