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

:root {
    --photo-card-size: calc(100vh / 3); /* デフォルト値 */

    --text-color-black: #555;
    --text-color-white: #ddd;
}

/* スマホ用（480px以下） */
@media screen and (max-width: 480px) {
    :root {
        --photo-card-size: calc(100vw * 2 / 3);
    }
    
    div.photos-container {
        width: 90%;
    }
}

/* PC・タブレット用（481px以上） - 横向き */
@media screen and (min-width: 481px) and (orientation: landscape) {
    :root {
        --photo-card-size: calc(100vh / 3);
    }
}

/* PC・タブレット用（481px以上） - 縦向き */
@media screen and (min-width: 481px) and (orientation: portrait) {
    :root {
        --photo-card-size: calc(100vw / 3);
    }
}

body {
    position: fixed;
    inset: 0;
    width: 100vw;
    height: 100vh;

    display: flex;
    justify-content: center;
    align-items: center;

    overflow: hidden;

    background-color: #f3fcff;

    font-family: "Noto Sans JP", sans-serif;
    font-optical-sizing: auto;
    font-weight: 500;
    font-style: normal;
}

header {
    position: absolute;
    top: 1rem;
    right: 1rem;

    display: flex;
    gap: 1rem;

    z-index: 999;
}

a.link {
    text-decoration: underline;
    color: #7b8c99;

    filter: brightness(1);
    transition: filter 0.25s ease;
}

a.link:hover {
    filter: brightness(1.5);
}

div.photos-container {
    width: 50%;
    aspect-ratio: 1 / 1;

    display: flex;
    justify-content: center;
    align-items: center;
}


div.photo-card-wrapper {
    position: absolute;
    width: 100%;
    height: 100%;

    display: flex;
    justify-content: center;
    align-items: center;
}

div.photo-card {
    width: var(--photo-card-size);
    aspect-ratio: 1 / 1;

    padding:1rem;

    background-color: #fff;
    box-shadow: 0px 0px 2px rgb(0 0 0 / 20%);
}

img.photo-card-image {
    width: 100%;
    aspect-ratio: 1 / 1;
}

div.photo-card-title {
    margin-top: 0.5rem;
    text-align: center;
    font-size: 0.75rem;
    color: var(--text-color-black);

    font-family: "Marcellus", serif;
    font-weight: 400;
    font-style: normal;
}

div.swipe-hint-overlay {
    position: absolute;
    top: 0;
    left: 0;

    width: 100vw;
    height: 100vh;

    opacity: 1;
    background-color: rgb(0 0 0 / 20%);

    transition: opacity 0.25s ease;

    pointer-events: none;
    z-index: 1000;
}

div.swipe-hint-box {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);

    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;

    width: auto;
    aspect-ratio: 1 / 1;

    padding: 1rem;

    background-color: rgb(0 0 0 / 80%);
    border-radius: 1rem;
}

svg.swipe-hint-arrow {
    width: 50%;
    fill: var(--text-color-white);
}

div.swipe-hint-text {
    margin-top: 1rem;
    text-align: center;
    font-size: 0.75rem;
    color: var(--text-color-white);
}