/* 銀河背景エフェクト用CSS */
/* 星空背景 */
#star-field {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -10;
    background: #0a0a0f;
}

.star {
    position: absolute;
    background: white;
    border-radius: 50%;
    animation: twinkle 5s infinite;
}

@keyframes twinkle {
    0%, 100% { opacity: 0.3; }
    50% { opacity: 1; }
}

/* 流れ星 */
.shooting-star {
    position: absolute;
    width: 2px;
    height: 2px;
    background: white;
    box-shadow: 0 0 6px white;
    border-radius: 50%;
}

.shooting-star::before {
    content: '';
    position: absolute;
    top: 0;
    left: -50px;
    width: 50px;
    height: 1px;
    background: linear-gradient(90deg, transparent, white);
    transform: translateY(-50%);
}

@keyframes shoot {
    0% {
        transform: translateX(0) translateY(0);
        opacity: 1;
    }
    100% {
        transform: translateX(300px) translateY(300px);
        opacity: 0;
    }
}

/* 惑星エフェクト */
.planet {
    position: absolute;
    border-radius: 50%;
    background: radial-gradient(circle at 30% 30%, #4facfe, #00427B);
    box-shadow: 0 0 20px rgba(79, 172, 254, 0.5);
}

.planet.small {
    width: 30px;
    height: 30px;
}

.planet.medium {
    width: 60px;
    height: 60px;
}

.planet.large {
    width: 100px;
    height: 100px;
}

/* 浮遊アニメーション */
@keyframes float {
    0%, 100% {
        transform: translateY(0) translateX(0) rotate(0deg);
    }
    33% {
        transform: translateY(-20px) translateX(10px) rotate(5deg);
    }
    66% {
        transform: translateY(10px) translateX(-10px) rotate(-5deg);
    }
}

.floating {
    animation: float 6s ease-in-out infinite;
}

/* 銀河の霧エフェクト */
.galaxy-fog {
    position: fixed;
    width: 200%;
    height: 200%;
    top: -50%;
    left: -50%;
    background: radial-gradient(ellipse at center, transparent 0%, rgba(79, 172, 254, 0.05) 50%, transparent 100%);
    animation: rotate 200s linear infinite;
    z-index: -5;
}

@keyframes rotate {
    from { transform: rotate(0deg); }
    to { transform: rotate(360deg); }
}

/* 光のパーティクル */
.light-particle {
    position: absolute;
    width: 4px;
    height: 4px;
    background: rgba(255, 255, 255, 0.8);
    border-radius: 50%;
    box-shadow: 0 0 10px rgba(255, 255, 255, 0.5);
    animation: particle-float 20s infinite linear;
}

@keyframes particle-float {
    0% {
        transform: translateY(100vh) translateX(0);
        opacity: 0;
    }
    10% {
        opacity: 1;
    }
    90% {
        opacity: 1;
    }
    100% {
        transform: translateY(-100vh) translateX(100px);
        opacity: 0;
    }
}

/* オーロラエフェクト */
.aurora {
    position: fixed;
    width: 100%;
    height: 100%;
    top: 0;
    left: 0;
    z-index: -8;
    opacity: 0.1;
    background: linear-gradient(135deg, transparent 0%, rgba(79, 172, 254, 0.1) 25%, rgba(221, 101, 0, 0.1) 50%, transparent 75%);
    animation: aurora-wave 30s ease-in-out infinite;
}

@keyframes aurora-wave {
    0%, 100% {
        transform: translateY(0) scale(1);
    }
    50% {
        transform: translateY(-50px) scale(1.1);
    }
}