:root {
    --color-blue: #3B82F6;
    --color-dblue: #0B2D71;
    --color-yellow: #FEC84B;
    --color-pink: #FF6B9D;
    --color-green: #7CCBA3;
    --color-white: #F8FBFF;
    --main-letter-color: #2E3A52;
    --padding-topbottom: clamp(1.5rem, 0.3696rem + 3.4783vw, 3.5rem);
    --padding-leftright: clamp(2.5rem, -0.3261rem + 8.6957vw, 7.5rem);
    --font-family-japanese: 'Noto Sans JP', sans-serif;
    --font-family-english: "Poppins", 'Noto Sans JP', sans-serif;
    --font-family-secttl: "M PLUS Rounded 1c", sans-serif;
}

*,
*::before,
*::after {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    text-rendering: optimizeLegibility;
    font-family: var(--font-family-japanese);
    /* macOS/iOS Safari/Chrome向けのアンチエイリアシング設定 (補完的) */
    -webkit-font-smoothing: antialiased;
    /* macOS Firefox向けのアンチエイリアシング設定 (補完的) */
    -moz-osx-font-smoothing: grayscale;
}


.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    margin: -1px;
    border: 0;
    padding: 0;
    white-space: nowrap;
    /* テキストの折り返しを防ぐ */
    clip: rect(0 0 0 0);
    /* 描画領域をクリップ */
    overflow: hidden;
    /* はみ出した内容を隠す */
}

#wrapper {
    box-sizing: border-box;
    position: relative;
    background-color: var(--background-main-color);
    color: var(--main-letter-color);
    font-family: var(--font-family-japanese);
    font-size: clamp(1rem, 0.867rem + 0.4255vw, 1.25rem);
    width: 100%;
    /* min-height: 100vh; */
    /* font-feature-settings: "palt"; */
    font-feature-settings: "palt" 1;
    line-break: strict;
    text-autospace: normal;
}

.big {
    display: block;
}

.sml {
    display: none;
}

img.img100 {
    width: 100%;
    display: block;
}

img.btn:hover {
    opacity: .8;
}

section.header {
    position: relative;
    width: 100%;
    /* background-color: #B8E0FE; */
    color: var(--color-dblue);
    padding: 16px 0;
    padding-top: 40px;
}

.header ul {
    display: flex;
    position: relative;
    width: fit-content;
    align-items: center;
    justify-content: center;
}

.header ul li {
    /* font-size: 20-32px; */
    font-size: clamp(1.25rem, 1.0649rem + 0.7792vw, 2rem);
    display: flex;
    font-weight: 600;
    font-family: var(--font-family-secttl);
    align-items: center;
    padding-left: 2rem;
    line-height: 1.2;
}

.header ul li:first-of-type {
    width: 14%;
    padding: 0;
}

/* #main {
    background-image: url(../../images/bg_onair.webp);
    background-repeat: no-repeat;
    background-size: auto 100vh;
    background-attachment: fixed;
    background-position: center;
} */

#main {
    position: relative;
    z-index: 0;
}

#main::before {
    content: "";
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100vh;
    height: 100dvh; /* スマホのアドレスバー伸縮対策 */
    background-image: url(../../images/bg_onair.webp);
    background-repeat: no-repeat;
    background-position: center;
    background-size: cover; /* または auto 100% */
    z-index: -1;
    pointer-events: none;
}
.container {
    width: 100%;
    padding: var(--padding-topbottom) var(--padding-leftright);
    padding-top: 16px;
    display: flex;
    justify-content: space-around;
}

.diaries {
    position: relative;
    width: fit-content;
}

.entries {
    position: relative;
    display: grid;
    grid-template-rows: auto;
    gap: 40px;
}

.entry {
    position: relative;
    background-color: rgba(255, 255, 255, 0.7);
    padding: 40px 80px;
}

.entry_date {
    position: relative;
    font-size: 80%;
    text-align: right;
}

.entry_title {
    /* font-size: 18-20px; */
    font-size: clamp(1.125rem, 1.0942rem + 0.1299vw, 1.25rem);
    font-weight: 600;
    border-bottom: dashed 1px var(--color-dblue);
    padding-bottom: 8px;
}

.entry_sentence {
    padding-top: 16px;
    position: relative;
    line-height: 1.8;
    /* font-size: 14-18px; */
    font-size: clamp(0.875rem, 0.8133rem + 0.2597vw, 1.125rem);
}

/* バックナンバー */
.calendar {
    position: sticky;
    top: 110px;
    /* align-self: flex-start; */
    background-color: rgba(255, 255, 255, 0.7);
    padding: 16px 32px;
    font-size: 16px;

    max-height: calc(100vh - 120px);
    overflow-y: auto;
    overscroll-behavior: contain;
    scrollbar-width: thin;
}


.calendar::-webkit-scrollbar {
    width: 6px;
}

.calendar::-webkit-scrollbar-thumb {
    background-color: rgba(0, 0, 0, 0.2);
    border-radius: 3px;
}

/* details全体の余白 */
details.back_accordion {
    margin-bottom: 1px;
}

/* 年タイトル */
details.back_accordion summary.back_list_year {
    list-style: none;
    cursor: pointer;
    position: relative;
    text-align: center;
    background-color: #6db8ea;
    font-size: 18px;
    font-weight: 600;
    color: #ffffff;
    padding: 16px 32px;
}

details.back_accordion summary.back_list_year::-webkit-details-marker {
    display: none;
}

details.back_accordion summary.back_list_year:hover {
    opacity: 0.8;
}

/* 月別リストのレイアウト */
.back_accordion .back_list_month {
    position: relative;
    margin: 0 auto;
    padding-top: 10px;
    text-align: center;
    padding: .5rem 0;
    color: var(--color-dblue);
}

.back_accordion .back_list_month a {
    color: var(--color-dblue);
    text-decoration: none;
}

.back_accordion .back_list_month a:hover {
    /* border-bottom:1px solid var(--color-dblue); */
    color: var(--color-blue);
}

details.back_accordion[open] .back_accordion_content {
    animation: accordionOpen 0.35s cubic-bezier(0.16, 1, 0.3, 1) forwards;
    padding: 16px 0;
}

details.back_accordion[open] .back_accordion_content.is-closing {
    animation: accordionClose 0.25s ease-out forwards;
}

@keyframes accordionOpen {
    0% {
        opacity: 0;
        transform: translateY(-8px);
    }

    100% {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes accordionClose {
    0% {
        opacity: 1;
        transform: translateY(0);
    }

    100% {
        opacity: 0;
        transform: translateY(-8px);
    }
}

details.back_accordion summary.back_list_year::before {
    content: "↓";
    display: inline-block;
    margin-right: 6px;
    transition: transform 0.3s ease;
}

/* 開いているとき：180度回転 */
details.back_accordion[open] summary.back_list_year::before {
    transform: rotate(180deg);
}

/*===============================================
●style.css 画面の横幅が1040pxまで
===============================================*/
@media screen and (max-width: 1040px) {
    .container {
        display: flex;
        flex-direction: column;
    }

    .diaries {
        width: 100%;
    }

    .calendar {
        position: static;
        top: auto;
        margin-top: 4rem;
        width: 100%;
        max-height: none;
        overflow-y: visible;
        overscroll-behavior: auto;
    }

}

/*===============================================
●style.css 画面の横幅が600pxまで　スマホ
===============================================*/
@media screen and (max-width: 600px) {
    .entry {
        padding: 16px 24px;
    }

    .container {
        padding: 0;
        width: 90%;
        margin: 0 auto;
    }

    .header ul li:first-of-type {
        width: 30%;
    }

    .sml {
        display: block;
    }
}

/*===============================================
●style.css 画面の横幅が360pxまで　スマホ
===============================================*/
@media screen and (max-width: 360px) {


    .big {
        display: none;
    }
}