/* ===== ベース ===== */
body {
    background: white;
}
.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

/* ===== ヘッダー ===== */
.header {
    background: black;
    display: flex;
    align-items: center;
    justify-content: flex-start;
    position: relative;
    width: 100%;
}
.header .title {
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
}
.header nav {
    margin-left: auto;
}

/* ===== ページレイアウト ===== */
.page-wrapper {
    display: flex;
    flex-wrap: wrap;
    align-items: flex-start;
}
.game-container {
    max-width: 1024px;
    margin: 0 auto;
}

/* ===== アプリエリア ===== */
.app-container {
    width: min(500px, 90vw);
    margin: 0 auto;
}
#my-app {
    display: block;
    width: min(500px, 90vw);
    height: calc(min(500px, 90vw) * 3 / 2);
    border: none;
    overflow: hidden;
    background-color: rgb(229, 233, 231);
}

/* ===== 関連アプリ ===== */
.right-column {
    width: 100%;
    flex-basis: 100%;
}
#link-list li a {
    flex-direction: row;
}

/* ===== 履歴 ===== */
.dice-history {
    margin: 20px auto 0;
    padding: 0 20px;
    max-width: 900px;
    color: #222;
}
.dice-history h3 {
    font-size: 1.2rem;
    font-weight: 700;
    margin-bottom: 10px;
    border-left: 4px solid #555;
    padding-left: 8px;
}
.dice-history-list {
    height: 140px;
    overflow-y: auto;
    background: #f5f5f5;
    border-radius: 8px;
    padding: 10px 16px;
    font-size: 1.05rem;
    line-height: 1.8;
}
.dice-history-list p {
    margin: 0;
    color: #444;
}
.dice-history-list p:first-child {
    font-weight: bold;
    color: #222;
}
.history-placeholder {
    color: #aaa;
}

/* ===== 説明文 ===== */
.game-description {
    margin: 30px auto 0;
    padding: 0 20px 20px;
    max-width: 900px;
    color: #222;
}
.game-description-inner {
    display: flex;
    flex-direction: column;
    gap: 20px;
}
.game-description article {
    background: #f5f5f5;
    border-radius: 8px;
    padding: 16px 20px;
}
.game-description h3 {
    font-size: 1.2rem;
    font-weight: 700;
    margin-bottom: 10px;
    border-left: 4px solid #555;
    padding-left: 8px;
}
.game-description ul {
    padding-left: 1.4em;
    line-height: 1.7;
    font-size: 1.05rem;
}

/* ===== Thanksセクション ===== */
.acknowledgement {
    margin: 20px auto 0;
    padding: 0 20px 20px;
    max-width: 900px;
    color: #222;
}
.acknowledgement h3 {
    font-size: 1.2rem;
    font-weight: 700;
    margin-bottom: 10px;
    border-left: 4px solid #555;
    padding-left: 8px;
}
.acknowledgement p {
    background: #f5f5f5;
    border-radius: 8px;
    padding: 16px 20px;
    line-height: 1.7;
    font-size: 1.05rem;
}

/* ===== デスクトップ (1025px+) ===== */
@media (min-width: 1025px) {
    .page-wrapper {
        flex-wrap: nowrap;
    }
    .page-wrapper > main {
        flex: 1 1 auto;
        min-width: 0;
    }
    .right-column {
        flex: 0 0 280px;
        width: 280px;
        align-self: flex-start;
    }
}