/* --- 基本設定 --- */
* { box-sizing: border-box; margin: 0; padding: 0; }
body { font-family: "Helvetica Neue", Arial, sans-serif; background-color: #f4ffc4; color: #000000; line-height: 1.6; }
.page-header {
    font-family: "Kaisei Decol", serif;
    top: 0;
    z-index: 1000;
    background-color: #c3d825;
    color: #227924;
    padding: 20px 25px;
    text-align: center;
}

.page-header h2 {
    font-family: "Kaisei Decol", serif;
    color: #227924;
    font-size: 2.5rem;
    letter-spacing: 0.1em;
}
.container { max-width: 1200px; margin: 0 auto; padding: 0 20px 50px; }
.circle-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(320px, 1fr)); gap: 30px; }

/* --- カードデザイン --- */
.circle-card {
    border: none;
    transition: transform 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275), box-shadow 0.4s ease;
}

/* マウスを乗せた時にふわっと浮き上がり、影を濃くする */
.circle-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 15px 35px rgba(0,0,0,0.15);
}

/* --- スライダー（無限増殖対応版） --- */
.circle-slider {
    position: relative;
    width: 100%;
    height: 240px;
    overflow: hidden;
    background: #000;
}

/* スライダー内の画像を少し暗くして文字を読みやすくする（お好みで） */
.circle-slider::after {
    content: '';
    position: absolute;
    top: 0; left: 0;
    width: 100%; height: 100%;
    background: linear-gradient(to bottom, transparent 60%, rgba(0,0,0,0.4));
    pointer-events: none;
}

/* カテゴリータグをよりスタイリッシュに */
.category-tag {
    background: #227924; /* 学祭カラー */
    backdrop-filter: blur(5px);
    border: 1px solid rgba(255,255,255,0.3);
    padding: 6px 15px;
    letter-spacing: 0.05em;
}

/* ボタンをイベント詳細風に */
.btn-detail {
    background: transparent;
    color: #c3d825;
    border: 2px solid #227924;
    transition: 0.3s;
}

.btn-detail:hover {
    background: #c3d825;
    color: #227924;
}

.circle-slider input[type="radio"] { display: none; }

.slides {
    display: flex;
    width: 100%;
    height: 100%;
    transition: transform 0.5s ease-in-out;
}
.slides img {
    width: 100%;
    height: 100%;
    flex-shrink: 0;
    object-fit: cover;
}

/* ★魔法のCSS：IDの末尾が何番かで移動量を決める（サークルが増えても有効） */
[id$="-1"]:checked ~ .slides { transform: translateX(0%); }
[id$="-2"]:checked ~ .slides { transform: translateX(-100%); }
[id$="-3"]:checked ~ .slides { transform: translateX(-200%); }
[id$="-4"]:checked ~ .slides { transform: translateX(-300%); }

/* --- 丸ボタンの連動設定 --- */
.controls {
    position: absolute;
    bottom: 15px;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    gap: 10px;
    z-index: 10;
}
.controls label {
    width: 12px;
    height: 12px;
    background: rgba(255, 255, 255, 0.5);
    border-radius: 50%;
    cursor: pointer;
    border: 1px solid rgba(0,0,0,0.2);
    transition: 0.3s;
}

/* ★魔法のCSS：何番目のラジオボタンがチェックされたかで、対応するラベルを光らせる */
.circle-slider input:nth-of-type(1):checked ~ .controls label:nth-of-type(1),
.circle-slider input:nth-of-type(2):checked ~ .controls label:nth-of-type(2),
.circle-slider input:nth-of-type(3):checked ~ .controls label:nth-of-type(3),
.circle-slider input:nth-of-type(4):checked ~ .controls label:nth-of-type(4) {
    background: #fff;
    transform: scale(1.3);
}

/* --- 装飾 --- */
.category-tag { position: absolute; top: 15px; right: 15px; background: rgba(0,0,0,0.6); color: #fff; padding: 4px 12px; border-radius: 20px; font-size: 0.7rem; font-weight: bold; }
.circle-content { padding: 20px; }
.circle-content h3 { margin-bottom: 8px; font-size: 1.25rem; }
.circle-content p { font-size: 0.9rem; color: #666; height: 3em; overflow: hidden; }
.circle-meta { display: flex; justify-content: space-between; align-items: center; border-top: 1px solid #eee; padding-top: 15px; }
.circle-meta span { font-size: 0.8rem; color: #e67e22; font-weight: bold; }
.btn-detail { background: #227924; color: #fff; padding: 6px 15px; border-radius: 6px; text-decoration: none; font-size: 0.8rem; font-weight: bold; }

/* 右下固定ボタン */
.back-home-button {
    position: fixed;
    bottom: 20px;
    right: 20px;
    background-color: #227924; /* 学祭の緑 */
    color: white;
    padding: 12px 20px;
    border-radius: 50px;
    text-decoration: none;
    font-weight: bold;
    font-family: sans-serif; /* 読みやすいゴシック体 */
    box-shadow: 0 4px 10px rgba(0,0,0,0.3);
    z-index: 1000;
    transition: 0.3s;
}

.back-home-button:hover {
    background-color: #c3d825; /* ホバーで明るい緑に */
    color: #227924;
    transform: translateY(-3px);
}