/* ====== 基本（スマホファースト） ====== */

/* SNS */

.sns-buttons-menu {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    justify-content: flex-start;
    padding: 0 10px;
    margin-top: 20px;
}

.sns-buttons-menu a {
  text-decoration: none;
}

.sns-buttons-menu button {
  background-color: white;
  border: 1px solid black;
  border-radius: 5px;
  color: black;
  cursor: pointer;
  font-size: 14px;
  padding: 5px 10px;
  transition: background-color 0.2s ease;
}

.sns-buttons-menu button:hover {
  background-color: #f0f0f0;
}


header nav ul {
    display: flex;
    flex-direction: column;
    gap: 0;
    padding: 0;
    list-style: none;
    width: 100%;
}

header nav ul li a,
header nav ul li.dropdown > span {
    display: block;
    padding: 12px;
    text-align: left;
    font-weight: bold;
    color: #333;
    text-decoration: none;
}

#menu-toggle {
    display: block;
    background: none;
    border: none;
    font-size: 1.8em;
    cursor: pointer;
    position: fixed;
    top: 10px;
    right: 10px;
}

/* スマホ用メニュー初期状態 */
nav#main-nav {
    position: fixed;
    top: 0;
    right: 0;
    height: 100%;
    width: 250px;
    background-color: rgba(255, 255, 255, 0.9);
    transform: translateX(100%);
    transition: transform 0.3s ease;
    z-index: 1000;
    flex-direction: column;
    padding-top: 50px; 
    display: none; /* 初期非表示 */
}

nav#main-nav.active {
    display: flex;          /* ハンバーガーで表示 */
    transform: translateX(0);
}

/* ドロップダウンはタップで表示 */
nav ul li .dropdown-menu {
    position: static;
    display: none;
}

nav ul li.dropdown.active .dropdown-menu {
    display: block;
}

/* 「問題集へ」リンクだけ */
nav#main-nav ul li.dropdown ul.dropdown-menu li a[href*="problem_novel.php"] {
    margin-left: 10px;
}

/* ホバー時はリンク・タイトル文字だけ赤くする */
nav#main-nav ul li > a:hover,
nav#main-nav ul li.dropdown > span:hover {
    background-color: #fcc;
    color: #900;
}

/* li全体には背景色を付けない */
nav#main-nav ul li {
    background-color: transparent;
}

/* dropdown メニューは li 内でも hover に関係なく表示 */
nav#main-nav ul li.dropdown .dropdown-menu {
    display: none;
    margin: 0;
    padding: 0;
}

nav#main-nav ul li.dropdown.active .dropdown-menu,
nav#main-nav ul li.dropdown:hover .dropdown-menu {
    display: block;
}

/* ====== PC用 ====== */
@media (min-width: 768px) {
    #menu-toggle {
        display: none;
    }

    nav#main-nav {
        position: static;
        display: flex;
        transform: none;
        transition: none;
        flex-direction: column;
        height: auto;
        width: 100%;
        background: none;
        padding: 0;
        justify-content: center;
    }

    .sns-buttons-menu {
         flex-wrap: nowrap;
         justify-content: center;
        margin: 10px;
    }

    header nav ul {
        flex-direction: row;
        gap: 20px;
        width: auto;
        justify-content: center;
        margin: 0;
        padding: 0;
        list-style: none;
    }

    /* dropdown li に relative を追加 */
    nav ul li.dropdown {
        position: relative;
    }

    nav ul li .dropdown-menu {
        position: absolute;
        display: none; /* 基本は非表示 */
        top: 100%;
        left: 0;
        background: #fff;
        border: 1px solid #ccc;
        padding: 5px 0;
        min-width: 180px;
        z-index: 1000;
    }

    /* hover または active でメニュー表示 */
    nav ul li.dropdown:hover .dropdown-menu,
    nav ul li.dropdown.active .dropdown-menu {
        display: block !important;
    }
}