html {
    scroll-behavior: smooth;
}

:root {
    /* ヘッダー */
    --header-h: 136px;
    --sil-h: 40px;
    --grid: 40px;
    --top: #2b3132;
    --mid: #6a6f71;
    --sil: #303438;
    --stripe-red: #d04633;
    --stripe-black: #111;
    --stripe-h: 12px;

    /* メイン */
    --tile-size: 60px;
    --col-a: #f5f6ec;
    --col-b: #f0f1e7;

}

body {
    margin: 0;
    min-height: 100vh;

    background-image:
        linear-gradient(to right,
            var(--col-b) 10%,
            rgba(255, 255, 255, 0) 30%,
            rgba(255, 255, 255, 0) 70%,
            var(--col-b) 90%),
        conic-gradient(var(--col-a) 0 90deg,
            var(--col-b) 0 180deg,
            var(--col-a) 0 270deg,
            var(--col-b) 0 360deg);
    background-size:
        100% 100%,
        calc(var(--tile-size) * 2) calc(var(--tile-size) * 2);

    font-family: "Noto Sans JP", sans-serif;
    font-optical-sizing: auto;
    font-style: normal;
}

section {
    margin-bottom: 200px;
}

/* ヘッダー */
header {
    display: block;

    /* ポジション */
    position: relative;
    color: #fff;
    padding: 17px 60px var(--header-h);

    /* 背景+グリッド */
    background-image:
        repeating-linear-gradient(0deg, var(--mid) 0 1px, transparent 1px var(--grid)),
        repeating-linear-gradient(90deg, var(--mid) 0 1px, transparent 1px var(--grid)),
        linear-gradient(to bottom, var(--top), var(--mid));
    background-size:
        var(--grid) var(--grid),
        var(--grid) var(--grid),
        100% 100%;
    overflow: hidden;
}

header::after {
    content: "";
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 12px;
    width: 100%;
    height: calc(var(--stripe-h) * 2);
    background: linear-gradient(to bottom,
            var(--stripe-red) 0 var(--stripe-h),
            var(--stripe-black) var(--stripe-h) calc(var(--stripe-h)*2));
}

#header-content {
    max-width: 1000px;
    width: 100%;
    margin-inline: auto;
}

header h1 {
    margin: 0;
    font-size: 5em;
    letter-spacing: 0.05em;
    margin-top: -0.2em;
    margin-bottom: -0.2em;
}

header p {
    margin: 0;
    margin-left: 0.1em;
    font-size: 1.8em;
    letter-spacing: 0.1em;
    font-weight: 450;
}

header::before {
    content: "";
    position: absolute;
    bottom: 0px;
    left: 0;
    width: 100%;
    height: 50px;
    background: var(--sil);
}

.silhouette {
    position: absolute;
    pointer-events: none;
    bottom: 50px;
    left: 50%;
}

#vesselSil {
    transform: translateX(-200%);
}

#citySil1 {
    transform: translateX(-70%);
    width: 300px;
}

#citySil2 {
    transform: translateX(-20%);
    width: 300px;
}

#airportSil {
    width: 250px;
    transform: translateX(115%);
}

#Sil {
    transform: translateX(-50%);
}

/* メインコンテンツ */
#content {
    max-width: 1000px;
    width: 100%;
    margin-inline: auto;
    padding: 24px 32px;
}

#content h2 {
    margin: 40px 0 16px;
    font-size: 2.75em;
    line-height: 1.1;
    text-align: left;
    letter-spacing: 0.15em;
}

#content p {
    margin: 0 0 48px;
    font-size: 1.2em;
    line-height: 1.6;
    text-align: left;
    word-break: break-word;
    overflow-wrap: anywhere;
}

.image1 {
    display: block;
    margin-top: 20px;
    margin-inline: auto;
    max-width: 100%;
    height: auto;
}

.gallery {
    max-width: 1000px;
    width: 100%;
    margin-inline: auto;
    padding: 24px 32px;
}

.gallery img {
    display: block;
    margin-top: 20px;
    margin-inline: auto;
    max-width: 1000px;
    height: auto;
}

/* フッター */
footer {
    background-color: #003b64;
    color: white;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 10px 20px;
    flex-wrap: wrap;
}

footer .logo {
    font-size: 1.2em;
}

footer .center {
    font-size: 1em;
    text-align: center;
    flex: 1;
}

footer a {
    color: white;
    text-decoration: none;
}

.back-to-top a img {
    display: block;
    width: 75px;
    height: auto;
}