/* ===== reset ===== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

/* ===== light mode ===== */
:root {
    --blue: #483d8b;
    --pink: #48b8ec;
    --bg: #d1eaee;
    --card: #ffffff;
    --text: #242d3a;
}

/* ===== dark mode ===== */
body.dark {
    --blue: #c5bdf8;
    --bg: #030f28;
    --card: #023182;
    --text: #e5e7eb;
}

/* ===== base ===== */
body {
    font-family: "Segoe UI","Hiragino Kaku Gothic ProN",sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.9;
    transition: background-color 0.6s ease, color 0.6s ease;
}

/* ===== hero ===== */
.hero {
    background: linear-gradient(135deg, var(--blue), var(--pink));
    color: white;
    text-align: center;
    padding: 80px 20px;
}

/* ===== nav ===== */
.nav {
    display: flex;
    justify-content: center;
    gap: 14px;
    padding: 16px;
    background: var(--card);
    transition: background-color 0.6s ease;
}

.nav a {
    text-decoration: none;
    color: var(--blue);
    font-weight: 600;
}

/* ===== width control ===== */
.container {
    max-width: 720px;   /* ← 横幅をしっかり絞る */
    margin: 60px auto;
    padding: 0 0px;
}

/* ===== card ===== */
.card {
    background: var(--card);
    border-radius: 16px;
    padding: 32px;
    margin-bottom: 50px;
    box-shadow: 0 12px 28px rgba(0,0,0,0.08);
    transform: translateY(20px);
    opacity: 0;
    animation: fadeUp 0.8s ease forwards;
}


/* セクションごとに少し遅延 */
.card:nth-child(1) { animation-delay: 0.1s; }
.card:nth-child(2) { animation-delay: 0.2s; }
.card:nth-child(3) { animation-delay: 0.3s; }
.card:nth-child(4) { animation-delay: 0.4s; }
.card:nth-child(5) { animation-delay: 0.5s; }
.card:nth-child(6) { animation-delay: 0.6s; }

.card h2 {
    margin-bottom: 14px;
    font-size: 22px;
    border-left: 4px solid var(--blue);
    padding-left: 10px;
}

/* ===== list ===== */
.list {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 10px;
}

.list li {
    list-style: none;
    background: rgba(0,0,0,0.04);
    padding: 10px;
    border-radius: 8px;
}

/* ===== button ===== */
.mode-btn {
    position: fixed;
    top: 15px;
    right: 15px;
    background: var(--card);
    border: none;
    padding: 8px 12px;
    border-radius: 50%;
    cursor: pointer;
    transition: transform 0.6s ease;
}

/* ===== footer ===== */
.footer {
    text-align: center;
    padding: 40px 20px;
    color: #9ca3af;
}

/* ===== animation ===== */
@keyframes fadeUp {
    to {
        transform: translateY(0);
        opacity: 1;
    }
}

/* ===== mobile ===== */
@media (max-width:600px) {
    .list {
        grid-template-columns: 1fr;
    }
}