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

body {
    font-family: 'Noto Sans JP', 'Hiragino Kaku Gothic ProN', 'メイリオ', sans-serif;
    background: radial-gradient(ellipse at bottom, #0d1b2a 0%, #1b263b 50%, #0f172a 100%);
    min-height: 100vh;
    padding: 20px;
    position: relative;
    color: white;
}

/* 背景の星のアニメーション */
body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-image: 
        radial-gradient(2px 2px at 20px 30px, rgba(255,255,255,0.3), transparent),
        radial-gradient(2px 2px at 40px 70px, rgba(255,255,255,0.2), transparent),
        radial-gradient(1px 1px at 90px 40px, rgba(255,255,255,0.5), transparent),
        radial-gradient(1px 1px at 130px 80px, rgba(255,255,255,0.3), transparent),
        radial-gradient(2px 2px at 160px 30px, rgba(255,255,255,0.4), transparent);
    background-repeat: repeat;
    background-size: 200px 100px;
    animation: twinkle 3s infinite;
    pointer-events: none;
    z-index: 0;
}

@keyframes twinkle {
    0%, 100% { opacity: 0.8; }
    50% { opacity: 0.4; }
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    background: rgba(15, 23, 42, 0.8);
    backdrop-filter: blur(12px);
    border-radius: 20px;
    box-shadow: 
        0 0 0 1px rgba(255, 255, 255, 0.05),
        0 25px 50px -12px rgba(0, 0, 0, 0.25);
    border: 1px solid rgba(59, 130, 246, 0.2);
    overflow: hidden;
    position: relative;
    z-index: 1;
}

.header {
    background: linear-gradient(135deg, rgba(96, 165, 250, 0.2) 0%, rgba(59, 130, 246, 0.2) 100%);
    padding: 40px;
    text-align: center;
    color: white;
    position: relative;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

h1 {
    font-size: 2.5em;
    margin-bottom: 10px;
    position: relative;
    z-index: 1;
    color: #ffffff;
    font-weight: bold;
    letter-spacing: 0.5px;
}

.subtitle {
    font-size: 1.1em;
    opacity: 0.95;
    position: relative;
    z-index: 1;
    color: #cbd5e1;
}

.main-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 40px;
    padding: 40px;
}

h3 {
    color: #e2e8f0;
    margin-bottom: 15px;
}

.left-panel, .right-panel {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.upload-area {
    border: 3px dashed rgba(96, 165, 250, 0.3);
    border-radius: 15px;
    padding: 40px;
    text-align: center;
    background: rgba(0, 0, 0, 0.3);
    transition: all 0.3s ease;
    cursor: pointer;
    position: relative;
}

.upload-area:hover {
    border-color: #60a5fa;
    background: rgba(59, 130, 246, 0.1);
    transform: scale(1.02);
}

.upload-area.dragover {
    border-color: #3b82f6;
    background: rgba(59, 130, 246, 0.2);
}

.upload-icon {
    font-size: 3em;
    margin-bottom: 10px;
}

#fileInput {
    display: none;
}

.controls {
    background: rgba(0, 0, 0, 0.3);
    border-radius: 15px;
    padding: 25px;
    border: 1px solid rgba(255, 255, 255, 0.1);
}

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

.control-group label {
    display: block;
    font-weight: bold;
    margin-bottom: 8px;
    color: #e2e8f0;
    font-size: 0.95em;
}

.control-group input[type="range"] {
    width: 100%;
    height: 8px;
    border-radius: 4px;
    background: linear-gradient(to right, #60a5fa, #3b82f6);
    outline: none;
    -webkit-appearance: none;
    appearance: none;
}

.control-group input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: white;
    cursor: pointer;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
}

.control-group input[type="color"] {
    width: 100%;
    height: 40px;
    border: none;
    border-radius: 8px;
    cursor: pointer;
}

.value-display {
    display: inline-block;
    background: rgba(59, 130, 246, 0.2);
    padding: 2px 8px;
    border-radius: 4px;
    margin-left: 10px;
    font-size: 0.9em;
    color: #60a5fa;
    font-weight: bold;
}

.preview-container {
    background: rgba(0, 0, 0, 0.3);
    border-radius: 15px;
    padding: 20px;
    text-align: center;
    min-height: 400px;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    border: 1px solid rgba(255, 255, 255, 0.1);
}

#previewCanvas {
    max-width: 100%;
    max-height: 500px;
    border-radius: 10px;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
}

.button-group {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 15px;
    margin-top: 20px;
}

.btn {
    padding: 15px 30px;
    font-size: 1.1em;
    font-weight: bold;
    border: none;
    border-radius: 10px;
    cursor: pointer;
    transition: all 0.3s ease;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.btn-primary {
    background: linear-gradient(135deg, #60a5fa 0%, #3b82f6 100%);
    color: white;
    grid-column: span 2;
    box-shadow: 0 4px 6px rgba(59, 130, 246, 0.2);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 20px rgba(59, 130, 246, 0.4);
}

.btn-secondary {
    background: rgba(100, 116, 139, 0.8);
    color: white;
    border: 1px solid rgba(255, 255, 255, 0.1);
}

.btn-secondary:hover {
    background: rgba(71, 85, 105, 0.9);
}

.btn-success {
    background: linear-gradient(135deg, #10b981 0%, #34d399 100%);
    color: white;
    box-shadow: 0 4px 6px rgba(16, 185, 129, 0.2);
}

.btn-success:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 20px rgba(16, 185, 129, 0.4);
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

#outputContainer {
    display: none;
    background: rgba(0, 0, 0, 0.3);
    border-radius: 15px;
    padding: 20px;
    margin-top: 20px;
    text-align: center;
    border: 1px solid rgba(255, 255, 255, 0.1);
}

#outputImage {
    max-width: 100%;
    max-height: 400px;
    border-radius: 10px;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
    margin-bottom: 20px;
}

.loading {
    display: none;
    text-align: center;
    padding: 20px;
}

.spinner {
    border: 4px solid rgba(255, 255, 255, 0.1);
    border-top: 4px solid #60a5fa;
    border-radius: 50%;
    width: 50px;
    height: 50px;
    animation: spin 1s linear infinite;
    margin: 0 auto 20px;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

@media (max-width: 768px) {
    .main-content {
        grid-template-columns: 1fr;
    }
    
    h1 {
        font-size: 2em;
    }
    
    .button-group {
        grid-template-columns: 1fr;
    }
    
    .btn-primary {
        grid-column: span 1;
    }
}

.footer {
    background: rgba(0, 0, 0, 0.2);
    padding: 30px;
    text-align: center;
    color: #94a3b8;
    font-size: 0.9em;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}