body { 
    font-family: "Helvetica Neue", Arial, "Hiragino Kaku Gothic ProN", "Hiragino Sans", Meiryo, sans-serif; 
    background: #f8f9fa; 
    color: #333333; 
    margin: 0; 
    padding: 20px; 
    line-height: 1.6; 
}
.container { max-width: 900px; margin: 0 auto; background: #fff; padding: 20px; border-radius: 8px; box-shadow: 0 2px 5px rgba(0,0,0,0.1); }
h1 { 
    font-size: clamp(14px, 8.00px + 1.56vw, 28px); 
    text-align: center; 
    color: #0f2537; 
    font-weight: 700;
    letter-spacing: 0.03em;
    margin: 10px 0 25px 0;
    position: relative;
    padding-bottom: 12px;
}
h1::after {
    content: "";
    display: block;
    width: 40px;
    height: 3px;
    background: #0066cc; 
    margin: 8px auto 0 auto;
    border-radius: 2px;
}

h2 { 
    font-size: clamp(14px, 8.00px + 1.56vw, 22px); 
    margin: -10px 10px 15px 10px; 
    text-align: center; 
    color: #0f2537; 
    font-weight: 600;
}

.nav-buttons { display: flex; justify-content: space-between; margin-bottom: 25px; gap: 10px; }
.btn { 
    display: inline-block; 
    padding: 10px 22px; 
    background: #0066cc; 
    color: #fff; 
    text-decoration: none; 
    border-radius: 3px; 
    border: none; 
    cursor: pointer; 
    font-size: 14px; 
    font-weight: 600;
    text-align: center;
    white-space: nowrap;
    transition: background 0.2s ease, transform 0.1s ease;
}
.btn:hover { background: #0052a3; }
.btn:active { transform: translateY(1px); }
.btn-danger { background: #d9383a; }
.btn-danger:hover { background: #b82c2e; }

form { background: #f9f9f9; padding: 20px; border: 1px solid #ddd; border-radius: 6px; margin-bottom: 30px; }
.form-group { margin-bottom: 15px; }
.form-group label { display: block; font-weight: bold; margin-bottom: 5px; }
.form-group input[type="text"] { width: 100%; padding: 8px; box-sizing: border-box; border: 1px solid #ccc; border-radius: 4px; font-size: 15px; }
.item-list { margin-top: 20px; }
.item-card { background: #fff; border: 1px solid #e0e0e0; border-radius: 6px; padding: 15px; margin-bottom: 20px; box-shadow: 0 1px 3px rgba(0,0,0,0.05); }
.item-header { display: flex; justify-content: space-between; flex-wrap: wrap; border-bottom: 1px solid #eee; padding-bottom: 8px; margin-bottom: 12px; gap: 8px; }
.item-tags { font-weight: bold; color: #7f8c8d; display: flex; flex-wrap: wrap; gap: 4px; }
.item-tags span { background: #e8f4fd; color: #1da1f2; padding: 2px 8px; border-radius: 3px; font-size: 13px; white-space: nowrap; }
.item-title { font-size: 18px; font-weight: bold; color: #2c3e50; margin: 5px 0; word-break: break-all; }
.item-body { display: flex; flex-direction: row; gap: 20px; width: 100%; max-width: 100%; box-sizing: border-box; }
.item-photo { width: 350px; height: 250px; object-fit: cover; border-radius: 4px; border: 1px solid #ddd; background: #fafafa; flex-shrink: 0; }
.item-desc { flex: 1; min-width: 0; white-space: pre-wrap; word-break: break-all; overflow-wrap: anywhere; }
.pagination { text-align: center; margin: 30px 0; font-size: 16px; display: flex; justify-content: center; flex-wrap: wrap; gap: 4px; }
.pagination a, .pagination span { padding: 5px 10px; text-decoration: none; border: 1px solid #ddd; color: #3498db; border-radius: 3px; white-space: nowrap; }
.pagination .current { background: #3498db; color: #fff; border: 1px solid #3498db; }
.pagination a:hover { background: #eee; }

/* ============================================================================
   各メディアクエリ対応（ブレイクポイント別調整）
   ============================================================================ */

/* 1. PC大画面（1024px以上） */
@media screen and (min-width: 1024px) {
    body { padding: 30px; }
    .container { padding: 30px; }
}

/* 2. タブレット・大（835px 〜 1023px） */
@media (min-width: 835px) and (max-width: 1023px) {
    .item-photo { width: 300px; height: 214px; }
}

/* 3. タブレット・小（744px 〜 834px）: このサイズから縦並びに切り替え */
@media (min-width: 744px) and (max-width: 834px) {
    .item-body { flex-direction: column; gap: 15px; }
    .item-photo { width: 100%; max-width: 450px; height: 320px; margin: 0 auto; }
}

/* 4. スマホ・大（541px 〜 743px） */
@media (min-width: 541px) and (max-width: 743px) {
    body { padding: 15px; }
    .container { padding: 15px; }
    form { padding: 15px; }
    .item-body { flex-direction: column; gap: 15px; }
    .item-photo { width: 100%; max-width: 100%; height: auto; max-height: 300px; margin: 0 auto; }
}

/* 5. スマホ・中（441px 〜 540px） */
@media (min-width: 441px) and (max-width: 540px) {
    body { padding: 10px; }
    .container { padding: 15px; }
    form { padding: 15px; }
    .item-body { flex-direction: column; gap: 12px; }
    .item-photo { width: 100%; height: auto; max-height: 260px; }
    .nav-buttons { flex-direction: column; gap: 8px; }
    .nav-buttons .btn { width: 100%; box-sizing: border-box; }
}

/* 6. スマホ・小（391px 〜 440px） */
@media (min-width: 391px) and (max-width: 440px) {
    body { padding: 8px; }
    .container { padding: 12px; }
    form { padding: 12px; }
    .item-body { flex-direction: column; gap: 12px; }
    .item-photo { width: 100%; height: auto; max-height: 240px; }
    .nav-buttons { flex-direction: column; gap: 8px; }
    .nav-buttons .btn { width: 100%; box-sizing: border-box; padding: 12px 10px; }
}

/* 7. スマホ・細（381px 〜 390px） */
@media (min-width: 381px) and (max-width: 390px) {
    body { padding: 6px; }
    .container { padding: 12px; }
    form { padding: 12px; }
    .item-body { flex-direction: column; gap: 10px; }
    .item-photo { width: 100%; height: auto; max-height: 220px; }
    .nav-buttons { flex-direction: column; gap: 6px; }
    .nav-buttons .btn { width: 100%; box-sizing: border-box; padding: 12px 10px; }
}

/* 8. スマホ・超細（375px 〜 380px） */
@media (min-width: 375px) and (max-width: 380px) {
    body { padding: 5px; }
    .container { padding: 10px; }
    form { padding: 10px; }
    .item-body { flex-direction: column; gap: 10px; }
    .item-photo { width: 100%; height: auto; max-height: 210px; }
    .nav-buttons { flex-direction: column; gap: 6px; }
    .nav-buttons .btn { width: 100%; box-sizing: border-box; padding: 12px 10px; }
    .pagination a, .pagination span { padding: 5px 8px; font-size: 14px; }
}

/* 9. スマホ・極小（374px以下） */
@media (max-width: 374px) {
    body { padding: 4px; }
    .container { padding: 8px; }
    form { padding: 10px; }
    .item-card { padding: 12px; }
    .item-body { flex-direction: column; gap: 10px; }
    .item-photo { width: 100%; height: auto; max-height: 180px; }
    .nav-buttons { flex-direction: column; gap: 6px; }
    .nav-buttons .btn { width: 100%; box-sizing: border-box; padding: 12px 10px; font-size: 13px; }
    .pagination a, .pagination span { padding: 4px 6px; font-size: 12px; margin: 0 1px; }
}