body {
    background: #050505;
    color: #00ff41;
    font-family: 'Courier New', monospace;
    margin: 0;
    background: linear-gradient(rgba(0, 0, 0, 0.8), rgba(0, 0, 0, 0.8)), url('背景面接.png');
    background-size: cover;
    background-attachment: fixed;
}

#os-container { max-width: 900px; margin: 0 auto; padding: 60px 20px; }

.card {
    border: 1px solid #00ff41;
    padding: 30px;
    margin: 25px 0;
    background: rgba(0, 20, 0, 0.7);
    backdrop-filter: blur(5px);
    transition: 0.3s;
}

.card:hover { border-color: #ff0000; box-shadow: 0 0 15px #ff0000; transform: scale(1.01); }

h1 { font-size: 2.7rem; text-align: center; text-transform: uppercase; }
.subtitle { font-size: 1.3rem; text-align: center; }

button {
    background: #ff0000;
    color: #fff;
    border: none;
    padding: 20px;
    width: 100%;
    cursor: pointer;
    font-weight: bold;
    text-transform: uppercase;
}
@keyframes blink { 0% { opacity: 0; } 50% { opacity: 1; } 100% { opacity: 0; } }

/* 画面ノイズ演出 */
.glitch-effect {
    animation: glitch 0.2s infinite;
}

@keyframes glitch {
    0% { transform: translate(2px, 2px); }
    50% { transform: translate(-2px, -2px); }
    100% { transform: translate(0, 0); }
}