/* ベーススタイル */
body {
    font-family: 'M PLUS Rounded 1c', sans-serif;
    background-color: #0d1117;
    color: #e6edf3;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    margin: 0;
    text-align: center;
    overflow: hidden;
    position: relative;
}

/* オープニング画面全体 */
#splash-screen {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: #0d1117;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    z-index: 1000;
    transition: opacity 1s ease-in-out, visibility 1s ease-in-out;
    opacity: 1;
    visibility: visible;
}

/* 背景の星アニメーション */
.starfield {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: radial-gradient(2px 2px at 20px 30px, #eee, rgba(0,0,0,0)),
                radial-gradient(2px 2px at 80px 70px, #eee, rgba(0,0,0,0)),
                radial-gradient(2px 2px at 120px 40px, #eee, rgba(0,0,0,0)),
                radial-gradient(2px 2px at 150px 90px, #eee, rgba(0,0,0,0));
    background-size: 200px 200px;
    animation: star-move 60s linear infinite;
    opacity: 0.8;
}

@keyframes star-move {
    from { background-position: 0 0; }
    to { background-position: 1000px 1000px; }
}

/* タイトル */
.splash-title {
    font-family: 'Orbitron', sans-serif;
    font-size: 3.8em;
    color: #61dafb;
    text-shadow: 0 0 15px rgba(97, 218, 251, 0.8), 0 0 30px rgba(97, 218, 251, 0.6);
    letter-spacing: 5px;
    margin-bottom: 20px;
    animation: typing 3s steps(12, end) forwards, glitch-text 0.5s infinite alternate 3s;
    overflow: hidden;
    white-space: nowrap;
    border-right: 3px solid #61dafb;
    max-width: 0;
}

@keyframes typing {
    from { max-width: 0; }
    to { max-width: 100%; }
}

@keyframes glitch-text {
    0% { transform: translate(0); text-shadow: 0 0 15px rgba(97, 218, 251, 0.8); }
    20% { transform: translate(-2px, 2px); text-shadow: 0 0 15px rgba(97, 218, 251, 0.8), 2px -2px 5px #e74c3c; }
    40% { transform: translate(-2px, -2px); text-shadow: 0 0 15px rgba(97, 218, 251, 0.8), -2px 2px 5px #f1c40f; }
    60% { transform: translate(2px, 2px); text-shadow: 0 0 15px rgba(97, 218, 251, 0.8), 2px 2px 5px #3498db; }
    80% { transform: translate(2px, -2px); text-shadow: 0 0 15px rgba(97, 218, 251, 0.8), -2px -2px 5px #2ecc71; }
    100% { transform: translate(0); text-shadow: 0 0 15px rgba(97, 218, 251, 0.8); }
}

/* オープニング画面のタイトル、スマホ対応 */
@media (max-width: 600px) {
    .splash-title {
        font-size: 2.5em;
        letter-spacing: 2px;
    }
}

/* プログラム製作者名 */
.splash-developer {
    font-family: 'Orbitron', sans-serif;
    font-size: 1.2em;
    color: #a7b7c7;
    margin-top: 10px;
    opacity: 0;
    animation: fade-in 1s forwards 3.5s;
}

.developer-name {
    font-size: 1.5em; /* 特に目立たせる */
    color: #4CAF50; /* 緑色で強調 */
    text-shadow: 0 0 10px rgba(76, 175, 80, 0.7);
    animation: glow 1.5s infinite alternate 4s; /* 光るアニメーション */
}

@keyframes fade-in {
    to { opacity: 1; }
}

@keyframes glow {
    from { text-shadow: 0 0 10px rgba(76, 175, 80, 0.7); }
    to { text-shadow: 0 0 20px rgba(76, 175, 80, 1), 0 0 30px rgba(76, 175, 80, 0.8); }
}

/* LOADING...テキスト */
.splash-loading {
    font-family: 'Orbitron', sans-serif;
    font-size: 1.5em;
    color: #ffffff;
    margin-top: 30px;
    animation: pulse-light 1.5s infinite alternate, fade-in 1s forwards 4.5s;
    opacity: 0;
}

@keyframes pulse-light {
    from { text-shadow: 0 0 5px #fff; }
    to { text-shadow: 0 0 15px #fff, 0 0 25px rgba(255, 255, 255, 0.5); }
}

/* メインコンテンツ（初期は非表示） */
#main-content {
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px);
    transition: opacity 1s ease-in-out, transform 1s ease-in-out, visibility 1s ease-in-out;
    padding-top: 20px;
    padding-bottom: 20px;
}

/* メインコンテンツ表示時のスクロールを許可 */
body.main-loaded {
    overflow-y: auto;
}


/* --- メインクイズ画面のスタイル --- */
.container {
    background-color: rgba(255, 255, 255, 0.05);
    backdrop-filter: blur(8px);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 20px;
    box-shadow: 0 5px 30px rgba(0, 0, 0, 0.5);
    max-width: 600px;
    width: 90%;
    padding: 30px;
    box-sizing: border-box;
    position: relative;
    z-index: 10;
}

header h1 {
    font-family: 'Orbitron', sans-serif;
    color: #61dafb;
    font-size: 2.5em;
    margin-bottom: 10px;
    text-shadow: 0 0 10px rgba(97, 218, 251, 0.5);
}

#question-count {
    color: #4CAF50;
    font-weight: bold;
    font-size: 1.2em;
    margin-bottom: 20px;
}

#quiz-area {
    margin-top: 20px;
}

#question {
    font-size: 1.6em;
    line-height: 1.6;
    margin-bottom: 30px;
    color: #e6edf3;
}

#choices-container {
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.choice-btn {
    padding: 15px;
    background-color: rgba(97, 218, 251, 0.1);
    border: 2px solid #61dafb;
    border-radius: 10px;
    color: #e6edf3;
    font-size: 1.1em;
    cursor: pointer;
    transition: background-color 0.3s, transform 0.2s, border-color 0.3s;
}

.choice-btn:hover {
    background-color: rgba(97, 218, 251, 0.3);
    transform: translateY(-3px);
}

.choice-btn.correct-answer {
    background-color: #4CAF50;
    border-color: #4CAF50;
    color: #fff;
}

.choice-btn.incorrect-answer {
    background-color: #e74c3c;
    border-color: #e74c3c;
    color: #fff;
}


#result-message {
    margin-top: 20px;
    font-weight: bold;
    font-size: 1.3em;
}

#result-message.correct {
    color: #4CAF50;
    text-shadow: 0 0 8px rgba(76, 175, 80, 0.6);
}

#result-message.incorrect {
    color: #e74c3c;
    text-shadow: 0 0 8px rgba(231, 76, 60, 0.6);
}

#score-area {
    margin-top: 40px;
}

#final-score {
    font-family: 'Orbitron', sans-serif;
    font-size: 2.5em;
    font-weight: bold;
    color: #61dafb;
    text-shadow: 0 0 10px rgba(97, 218, 251, 0.5);
}

#restart-btn {
    padding: 12px 25px;
    margin-top: 30px;
    background-color: #4CAF50;
    color: #0d1117;
    border: none;
    border-radius: 25px;
    cursor: pointer;
    font-size: 1.1em;
    font-weight: bold;
    transition: background-color 0.3s ease, transform 0.2s ease, box-shadow 0.3s ease;
}

#restart-btn:hover {
    background-color: #61dafb;
    transform: scale(1.05);
    box-shadow: 0 0 15px rgba(97, 218, 251, 0.7);
}

.hidden {
    display: none;
}

footer {
    margin-top: 50px;
    font-size: 0.9em;
    color: #a7b7c7;
    line-height: 1.5;
}