* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}
body {
    font-family: "Helvetica Neue", Arial, "Hiragino Kaku Gothic ProN", "Hiragino Sans", Meiryo, sans-serif;
    background-color: #12161a;
    color: #e2e8f0;
    line-height: 1.6;
    padding: 10px; /* 最小画面向けの狭い余白 */
}
.container {
    width: 100%;
    margin: 0 auto;
}
h1 {
    text-align: center;
    color: #ffffff;
    letter-spacing: 1px;
    font-weight: 300;
    border-bottom: 1px solid #232930;
    padding-bottom: 10px;
}
.region-section {
    margin-bottom: 25px;
}
.region-title {
    font-size: 15px;
    border-left: 4px solid #00adb5;
    padding-left: 10px;
    margin-bottom: 12px;
    color: #00adb5;
    font-weight: bold;
    letter-spacing: 1px;
}
.time-grid {
    display: grid;
    gap: 10px;
}
.time-card {
    background: #1e252b;
    border-radius: 6px;
    padding: 12px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.3);
    border: 1px solid #2c353d;
}
.time-card.jpt {
    border: 1px solid #ff4757;
    background: linear-gradient(145deg, #241c20, #1e252b);
    box-shadow: 0 4px 20px rgba(255, 71, 87, 0.15);
}
.time-card.jpt .city-name {
    color: #ff4757;
}
.city-name {
    font-weight: bold;
    color: #ffffff;
}
.country-info {
    font-size: 11px;
    color: #94a3b8;
    margin-bottom: 6px;
}
.current-time {
    font-weight: bold;
    color: #00ffcc;
    font-family: "Consolas", "Courier New", Courier, monospace;
    text-shadow: 0 0 10px rgba(0, 255, 204, 0.2);
}
.current-date {
    font-size: 11px;
    color: #94a3b8;
    margin-top: 2px;
}
.button-area {
    text-align: center;
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
}
.btn {
    display: inline-block;
    text-decoration: none;
    border-radius: 4px;
    font-weight: bold;
    letter-spacing: 1px;
    transition: background-color 0.2s, box-shadow 0.2s;
    border: 1px solid transparent;
    cursor: pointer;
    text-align: center;
}
.btn-refresh {
    background-color: transparent;
    border-color: #00adb5;
    color: #00adb5;
}
.btn-refresh:hover {
    background-color: #00adb5;
    color: #12161a;
    box-shadow: 0 0 15px rgba(0, 173, 181, 0.4);
}
.btn-home {
    background-color: transparent;
    border-color: #64748b;
    color: #e2e8f0;
}
.btn-home:hover {
    background-color: #64748b;
    color: #ffffff;
    box-shadow: 0 0 15px rgba(100, 116, 139, 0.4);
}
@media screen and (min-width: 1024px) {
    body { padding: 30px; }
    .container { max-width: 1200px; }
    h1 { font-size: 28px; margin-bottom: 45px; padding-bottom: 15px; }
    .region-section { margin-bottom: 45px; }
    .region-title { font-size: 18px; margin-bottom: 20px; }
    .time-grid { grid-template-columns: repeat(4, 1fr); gap: 20px; }
    .time-card { padding: 20px; }
    .city-name { font-size: 17px; margin-bottom: 6px; }
    .current-time { font-size: 26px; }
    .button-area { margin-top: 60px; gap: 20px; }
    .btn { padding: 14px 45px; font-size: 15px; }
}
@media (min-width: 835px) and (max-width: 1023px) {
    body { padding: 25px; }
    .container { max-width: 960px; }
    h1 { font-size: 25px; margin-bottom: 35px; }
    .region-section { margin-bottom: 35px; }
    .time-grid { grid-template-columns: repeat(3, 1fr); gap: 15px; }
    .time-card { padding: 18px; }
    .city-name { font-size: 16px; }
    .current-time { font-size: 24px; }
    .button-area { margin-top: 50px; gap: 15px; }
    .btn { padding: 12px 40px; font-size: 14px; }
}
@media (min-width: 744px) and (max-width: 834px) {
    body { padding: 20px; }
    .container { max-width: 800px; }
    h1 { font-size: 23px; margin-bottom: 30px; }
    .time-grid { grid-template-columns: repeat(3, 1fr); gap: 12px; }
    .current-time { font-size: 21px; }
    .button-area { margin-top: 40px; gap: 15px; }
    .btn { padding: 12px 35px; font-size: 14px; }
}
@media (min-width: 541px) and (max-width: 743px) {
    body { padding: 20px; }
    .container { max-width: 700px; }
    h1 { font-size: 22px; margin-bottom: 25px; }
    .time-grid { grid-template-columns: repeat(2, 1fr); gap: 12px; }
    .current-time { font-size: 22px; }
    .button-area { margin-top: 40px; gap: 12px; }
    .btn { padding: 12px 30px; font-size: 14px; }
}
@media (min-width: 441px) and (max-width: 540px) {
    body { padding: 15px; }
    h1 { font-size: 20px; margin-bottom: 20px; }
    .time-grid { grid-template-columns: repeat(2, 1fr); gap: 10px; }
    .city-name { font-size: 14px; }
    .current-time { font-size: 18px; }
    .button-area { margin-top: 35px; gap: 10px; width: 100%; }
    .btn { width: 48%; padding: 12px 0; font-size: 13px; }
}
@media (min-width: 391px) and (max-width: 440px) {
    body { padding: 12px; }
    h1 { font-size: 19px; margin-bottom: 20px; }
    .time-grid { grid-template-columns: 1fr; gap: 10px; }
    .city-name { font-size: 15px; }
    .current-time { font-size: 20px; }
    .button-area { margin-top: 30px; flex-direction: column; gap: 10px; }
    .btn { width: 100%; max-width: 280px; padding: 12px 0; font-size: 14px; }
}
@media (min-width: 381px) and (max-width: 390px) {
    h1 { font-size: 19px; margin-bottom: 18px; }
    .time-grid { grid-template-columns: 1fr; }
    .city-name { font-size: 15px; }
    .current-time { font-size: 20px; }
    .button-area { margin-top: 30px; flex-direction: column; gap: 10px; }
    .btn { width: 100%; max-width: 260px; padding: 11px 0; font-size: 14px; }
}
@media (min-width: 375px) and (max-width: 380px) {
    h1 { font-size: 18px; margin-bottom: 15px; }
    .time-grid { grid-template-columns: 1fr; }
    .time-card { padding: 12px 15px; }
    .city-name { font-size: 14px; }
    .current-time { font-size: 19px; }
    .button-area { margin-top: 25px; flex-direction: column; gap: 8px; }
    .btn { width: 100%; max-width: 250px; padding: 11px 0; font-size: 13px; }
}
@media (max-width: 374px) {
    body { padding: 8px; }
    h1 { font-size: 17px; margin-bottom: 15px; }
    .region-title { font-size: 14px; }
    .time-grid { grid-template-columns: 1fr; gap: 8px; }
    .time-card { padding: 10px; }
    .city-name { font-size: 13px; }
    .current-time { font-size: 18px; }
    .button-area { margin-top: 25px; flex-direction: column; gap: 8px; }
    .btn { width: 100%; padding: 10px 0; font-size: 13px; }
}