:root {
    --bg-dark: #0b0f19;
    --glass-bg: rgba(17, 24, 39, 0.6);
    --glass-border: rgba(255, 255, 255, 0.1);
    --text-primary: #ffffff;
    --text-secondary: #9ca3af;
    --accent-blue: #3b82f6;
    --accent-purple: #8b5cf6;
    --danger: #ef4444;
    --success: #10b981;
}

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

body {
    background-color: var(--bg-dark);
    color: var(--text-primary);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    overflow-x: hidden;
    position: relative;
}

/* Background Effects */
.background-effects {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    z-index: -1;
    overflow: hidden;
}

.glow-orb {
    position: absolute;
    width: 500px;
    height: 500px;
    border-radius: 50%;
    filter: blur(100px);
    opacity: 0.4;
    animation: float 10s infinite alternate ease-in-out;
}

.glow-orb.blue {
    top: -100px;
    left: -100px;
    background: radial-gradient(circle, var(--accent-blue), transparent 70%);
}

.glow-orb.purple {
    bottom: -100px;
    right: -100px;
    background: radial-gradient(circle, var(--accent-purple), transparent 70%);
    animation-delay: -5s;
}

@keyframes float {
    0% { transform: translate(0, 0) scale(1); }
    100% { transform: translate(50px, 50px) scale(1.1); }
}

/* Main Container */
.container {
    width: 100%;
    max-width: 900px;
    padding: 2.5rem;
    margin: 2rem;
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

.glass-panel {
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    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;
}

header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    background: linear-gradient(135deg, #fff, #a5b4fc);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    display: inline-flex;
    align-items: center;
    gap: 10px;
}

.badge {
    font-size: 0.8rem;
    background: linear-gradient(135deg, var(--accent-blue), var(--accent-purple));
    color: white;
    padding: 2px 8px;
    border-radius: 12px;
    -webkit-text-fill-color: white;
}

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

/* Settings Panel */
.settings-panel {
    display: flex;
    gap: 1.5rem;
    background: rgba(0, 0, 0, 0.2);
    padding: 1.5rem;
    border-radius: 16px;
    border: 1px solid var(--glass-border);
}

.input-group {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.input-group label {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-secondary);
}

.input-group label i {
    margin-right: 5px;
    color: var(--accent-blue);
}

.input-group input, .custom-select select {
    width: 100%;
    padding: 0.8rem 1rem;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--glass-border);
    border-radius: 8px;
    color: white;
    font-size: 1rem;
    outline: none;
    transition: all 0.3s ease;
}

.input-group input:focus, .custom-select select:focus {
    border-color: var(--accent-blue);
    box-shadow: 0 0 0 2px rgba(59, 130, 246, 0.2);
}

.custom-select {
    position: relative;
}

.custom-select select {
    appearance: none;
    cursor: pointer;
}

.custom-select select option {
    background: var(--bg-dark);
    color: white;
}

.select-icon {
    position: absolute;
    right: 15px;
    top: 50%;
    transform: translateY(-50%);
    pointer-events: none;
    color: var(--text-secondary);
}

/* Upload Zone */
.upload-zone {
    border: 2px dashed var(--glass-border);
    border-radius: 16px;
    padding: 4rem 2rem;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s ease;
    background: rgba(0, 0, 0, 0.1);
}

.upload-zone:hover, .upload-zone.dragover {
    border-color: var(--accent-blue);
    background: rgba(59, 130, 246, 0.05);
    transform: translateY(-2px);
}

.upload-icon {
    font-size: 3rem;
    color: var(--accent-blue);
    margin-bottom: 1rem;
    transition: transform 0.3s ease;
}

.upload-zone:hover .upload-icon {
    transform: translateY(-5px);
}

.upload-content h3 {
    font-size: 1.2rem;
    margin-bottom: 0.5rem;
}

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

.upload-content span {
    color: var(--accent-blue);
    text-decoration: underline;
}

/* Loading Zone */
.loading-zone {
    text-align: center;
    padding: 3rem 0;
}

.spinner {
    width: 50px;
    height: 50px;
    border: 3px solid rgba(255, 255, 255, 0.1);
    border-radius: 50%;
    border-top-color: var(--accent-purple);
    animation: spin 1s ease-in-out infinite;
    margin: 0 auto 1rem auto;
}

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

.hidden {
    display: none !important;
}

/* Result Zone & Slider */
.result-zone {
    display: flex;
    flex-direction: column;
    gap: 2rem;
    align-items: center;
}

.comparison-slider {
    position: relative;
    width: 100%;
    max-width: 800px;
    border-radius: 16px;
    overflow: hidden;
    background: #e5e7eb url('data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9hAAAAMUlEQVQ4T2NkYGAQYcAP3uCTZhw1gGGYhAGBZIA/ENFMDD6BKBphRoxGgMB+B138AAAAAP//Yh8wBwAAAABJRU5ErkJggg==') repeat;
    aspect-ratio: 16/9;
    box-shadow: 0 10px 30px rgba(0,0,0,0.5);
}

.slider-image {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    object-fit: contain;
}

/* The wrapper that will be clipped */
.clip-wrapper {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    clip-path: polygon(0 0, 50% 0, 50% 100%, 0 100%); /* Bắt đầu ở giữa */
}

/* Image input range */
.slider-control {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: transparent;
    appearance: none;
    -webkit-appearance: none;
    z-index: 10;
    margin: 0;
    outline: none;
    cursor: ew-resize;
}

.slider-control::-webkit-slider-thumb {
    appearance: none;
    -webkit-appearance: none;
    width: 40px;
    height: 100vh; /* Cao bằng cả màn hình để click đâu cũng dính */
    background: transparent;
    cursor: ew-resize;
}

/* Đường kẻ chia cắt */
.slider-line {
    position: absolute;
    top: 0;
    bottom: 0;
    left: 50%;
    width: 4px;
    background: white;
    z-index: 5;
    pointer-events: none;
    transform: translateX(-50%);
    box-shadow: 0 0 10px rgba(0,0,0,0.5);
}

.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;
    color: var(--bg-dark);
    box-shadow: 0 0 10px rgba(0,0,0,0.5);
}

/* Buttons */
.action-buttons {
    display: flex;
    gap: 1rem;
    width: 100%;
}

.btn {
    flex: 1;
    padding: 1rem 1.5rem;
    border-radius: 12px;
    border: none;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 8px;
    transition: all 0.3s ease;
}

.btn-primary {
    background: linear-gradient(135deg, var(--accent-blue), var(--accent-purple));
    color: white;
}

.btn-primary:hover {
    box-shadow: 0 10px 20px -10px var(--accent-purple);
    transform: translateY(-2px);
}

.btn-secondary {
    background: rgba(255, 255, 255, 0.1);
    color: white;
    border: 1px solid var(--glass-border);
}

.btn-secondary:hover {
    background: rgba(255, 255, 255, 0.15);
}

/* Toast */
.toast {
    position: fixed;
    bottom: 30px;
    left: 50%;
    transform: translateX(-50%) translateY(100px);
    background: var(--danger);
    color: white;
    padding: 1rem 2rem;
    border-radius: 8px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.3);
    font-weight: 600;
    transition: transform 0.3s cubic-bezier(0.68, -0.55, 0.265, 1.55);
    z-index: 1000;
}

.toast.show {
    transform: translateX(-50%) translateY(0);
}

/* Responsive */
@media (max-width: 768px) {
    .settings-panel {
        flex-direction: column;
    }
    .action-buttons {
        flex-direction: column;
    }
}