html, body {
    margin: 0;
    padding: 0;
    height: 100%;
    /* overflow: hidden; */
    font-family: 'Segoe UI', sans-serif;
    background: linear-gradient(to right top, #60efff, #0061ff);
    position: relative;
}

.login-container {
    display: flex;
    justify-content: center;
    align-items: center;
    position: relative;
    z-index: 2;
}

.login-card {
    background: rgba(255, 255, 255, 0.9);
    padding: 2rem;
    border-radius: 12px;
    width: 400px;
    box-shadow: 0 10px 40px rgba(0,0,0,0.4);
    z-index: 2;
}

.login-card h2 {
    text-align: center;
    margin-bottom: 1.5rem;
    color: #1e3c72;
    font-weight: bold;
}

.form-control:focus {
    box-shadow: 0 0 0 0.2rem rgba(30, 60, 114, 0.3);
    border-color: #2a5298;
}

.btn-primary {
    background-color: #2a5298;
    border-color: #1e3c72;
}

.btn-primary:hover {
    background-color: #1e3c72;
}

/* 点の定義 */
.dot {
    position: absolute;
    width: 12px;
    height: 12px;
    background: radial-gradient(circle, #ffffffaa, #ffffff11);
    border-radius: 50%;
    animation: float 10s infinite ease-in-out;
    opacity: 0.5;
    filter: blur(2px);
}

/* アニメーションの内容：ふわっと移動し拡大縮小 */
@keyframes float {
    0% { transform: translateY(0) scale(1); opacity: 0.4; }
    50% { transform: translateY(-60px) scale(1.8); opacity: 0.8; }
    100% { transform: translateY(0) scale(1); opacity: 0.4; }
}

/* 背景ライン風（ネットワーク） */
.bg-lines::before {
    content: "";
    position: absolute;
    width: 100%;
    height: 100%;
    background-image: 
    linear-gradient(white 1px, transparent 1px),
    linear-gradient(to right, white 1px, transparent 1px);
    background-size: 80px 80px;
    opacity: 0.05;
    z-index: 0;
}