/* ----- 基本設定 & 変数 ----- */
:root {
    --primary-light: #9acaff;
    --primary-medium: #7eafe2;
    --primary-dark: #269efa;
    --font-color-dark: #333;
    --font-color-light: #555;
    --background-white: #fff;
}
*, *::before, *::after {
    box-sizing: border-box;
}
html {
    scroll-behavior: smooth;
    scroll-padding-top: 80px; /* 固定ヘッダーの高さ分 */
}
body {
    font-family: 'Noto Sans JP', sans-serif;
    margin: 0;
    padding: 0;
    line-height: 1.8; /* サイト全体で統一 */
    color: var(--font-color-dark);
    background-color: var(--background-white);
}
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
}

/* ----- 追従ヘッダー ----- */
.site-header {
    position: sticky;
    top: 0;
    width: 100%;
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    z-index: 1000;
    box-shadow: 0 2px 4px rgba(0,0,0,0.05);
}
.site-header .container {
    display: flex;
    align-items: center;
    justify-content: flex-start;
    padding-top: 15px;
    padding-bottom: 15px;
    height: 50px;
}
.logo-link {
    display: flex;
    align-items: center;
    text-decoration: none;
}
.logo-image {
    height: 30px;
    width: auto;
}
.site-title {
    font-family: "duper", sans-serif;
    font-weight: 400;
    font-style: italic;
    letter-spacing: 0.25em;
    font-size: 18px;
    color: #000;
}

/* ----- コピーライトフッター ----- */
.site-footer {
    background-color: var(--primary-dark);
    color: #fff;
    padding: 20px;
    text-align: center;
}
.site-footer p {
    margin: 0;
    font-size: 14px;
    margin-bottom: 15px;
}
.footer-nav a {
    color: #fff;
    text-decoration: none;
    font-size: 14px;
    margin: 0 15px;
    transition: text-decoration 0.3s;
}
.footer-nav a:hover {
    text-decoration: underline;
}

/* ----- トップへ戻るボタン ----- */
#back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    background-color: #ff6b69;
    color: #fff;
    border: none;
    border-radius: 50%;
    width: 50px;
    height: 50px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s, visibility 0.3s, transform 0.3s, bottom 0.3s;
    z-index: 1000;
    box-shadow: 0 4px 8px rgba(0,0,0,0.1);
}
#back-to-top.show {
    opacity: 1;
    visibility: visible;
}
#back-to-top:hover {
    opacity: 0.8;
}
a {
    color: var(--primary-dark);
    text-decoration: none;
}