body, html {
    margin: 0;
    padding: 0;
    overflow: hidden;
}
#galaxy {
    position: absolute;
    width: 100vw;
    height: 100vh;
    background: radial-gradient(ellipse at bottom, #1e3c72 0%, #000 100%);
    z-index: -1;
}
.star {
    position: absolute;
    background-color: #fff;
    border-radius: 50%;
    opacity: 0;
    animation: appear 3s forwards, flicker 1.5s infinite ease-in-out;
    z-index: -1;
}
.big-star {
    width: 4px;
    height: 4px;
}
.medium-star {
    width: 2px;
    height: 2px;
}
.small-star {
    width: 1px;
    height: 1px;
}

@keyframes flicker {
    0%, 100% { opacity: 0; }
    50% { opacity: 1; }
}
@keyframes appear {
    to { opacity: 1; }
}
.form-check {
    display: flex;
    align-items: center;
}
.form-check-input {
    margin-right: 10px;
}
.login-panel {
    position: absolute;
    width: 350px;
    height: auto;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    background-color: rgba(255, 255, 255, 0.8);
    border-radius: 20px;
    padding: 30px;
    box-shadow: 0px 8px 16px 0px rgba(0,0,0,0.2);
    text-align: center;
    z-index: 1;
}
.login-panel h2 {
    margin-bottom: 20px;
    color: #333;
}
.login-panel input {
    width: 100%;
    padding: 10px;
    margin: 10px 0;
    display: inline-block;
    border: 1px solid #ccc;
    border-radius: 4px;
    box-sizing: border-box;
}
.btn-primary {
    width: 100%;
    background-color: #4CAF50;
    color: white;
    padding: 14px 20px;
    margin: 8px 0;
    border: none;
    border-radius: 4px;
    cursor: pointer;
}
#saturn-container {
    position: absolute;
    bottom: 10%;
    left: 30%;
    z-index: 1;
}
#saturn {
    fill: #FF6347; /* 修改土星顏色 */
}
#ring {
    fill: none;
    stroke: #DAA520; /* 修改土星環顏色 */
    stroke-width: 5;
    transform-origin: center;
    transform: rotate(15deg);
    opacity: 0.8;
}

/* RWD */
@media (max-width: 768px) {
    .login-panel {
        width: 300px;
    }
    #saturn-container {
        bottom: 5%;
        left: 15%;
    }
}
@media (max-width: 480px) {
    .login-panel {
        width: 250px;
        padding: 20px;
    }
    #saturn-container {
        bottom: 3%;
        left: 10%;
    }
}