/* ============================================================
   header.css — 全ページ共通のシェル（ヘッダー / ドロワー / フッター）
   ------------------------------------------------------------
   トップページ(index.html)も下層ページもこれを読む。
   本文の組版は下層専用の site.css 側にあるので、ここには
   body / main / html への指定を一切置かないこと。
   （トップは lenis や全画面レイアウトを持っており、
     それらに干渉させないための分割）
   ============================================================ */

/* --- Layout ----------------------------------------------- */

.shell {
    width: 100%;
    max-width: 1120px;
    margin-inline: auto;
    padding-inline: 1.5rem;
}

@media (min-width: 768px) {
    .shell {
        padding-inline: 2.5rem;
    }
}

/* --- Header ----------------------------------------------- */


.site-header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 100;
    height: 5rem;
    display: flex;
    align-items: center;
    border-bottom: 1px solid transparent;
    transition:
        background-color 0.4s ease,
        border-color 0.4s ease,
        backdrop-filter 0.4s ease;
}

/* スクロールで背景が立ち上がる（JSが .is-scrolled を付ける） */
.site-header.is-scrolled {
    background: var(--glass-bg);
    border-bottom-color: var(--glass-border);
    -webkit-backdrop-filter: blur(12px);
    backdrop-filter: blur(12px);
}

.site-header__inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 2rem;
    width: 100%;
}

/* ロゴ: mask を使うことで単色SVGがテーマ色に追従する */
.site-logo {
    display: block;
    width: 8.5rem;
    height: 1.1rem;
    background-color: var(--text-main);
    -webkit-mask: url("/assets/images/logo.svg") no-repeat left center;
    mask: url("/assets/images/logo.svg") no-repeat left center;
    -webkit-mask-size: contain;
    mask-size: contain;
    transition: opacity 0.3s ease;
}

.site-logo:hover {
    opacity: 0.6;
}

/* --- Nav -------------------------------------------------- */

.site-nav {
    display: none;
    align-items: center;
    gap: 2rem;
}

@media (min-width: 900px) {
    .site-nav {
        display: flex;
    }
}

.site-nav__link {
    position: relative;
    font-size: 0.8125rem;
    letter-spacing: 0.04em;
    font-weight: 500;
    color: var(--text-sub);
    padding-block: 0.4rem;
    transition: color 0.3s ease;
}

.site-nav__link::after {
    content: "";
    position: absolute;
    left: 0;
    bottom: 0;
    width: 100%;
    height: 1px;
    background: currentColor;
    transform: scaleX(0);
    transform-origin: right;
    transition: transform 0.4s cubic-bezier(0.22, 1, 0.36, 1);
}

.site-nav__link:hover {
    color: var(--text-main);
}

.site-nav__link:hover::after,
.site-nav__link[aria-current="page"]::after {
    transform: scaleX(1);
    transform-origin: left;
}

.site-nav__link[aria-current="page"] {
    color: var(--text-main);
}

/* Contact は「操作」なので他のナビ項目と別扱いのボタンにする */
.site-cta {
    display: none;
    align-items: center;
    font-size: 0.8125rem;
    letter-spacing: 0.04em;
    font-weight: 500;
    padding: 0.6rem 1.4rem;
    border: 1px solid var(--glass-border);
    border-radius: 999px;
    color: var(--text-main);
    transition:
        background-color 0.3s ease,
        color 0.3s ease,
        border-color 0.3s ease;
}

@media (min-width: 900px) {
    .site-cta {
        display: inline-flex;
    }
}

.site-cta:hover {
    background: var(--text-main);
    color: var(--bg-main);
    border-color: var(--text-main);
}

/* --- Header tools (theme toggle / burger) ----------------- */

.header-tools {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.icon-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 2.5rem;
    height: 2.5rem;
    border-radius: 999px;
    border: 1px solid transparent;
    color: var(--text-sub);
    transition:
        color 0.3s ease,
        border-color 0.3s ease;
}

.icon-btn:hover {
    color: var(--text-main);
    border-color: var(--glass-border);
}

.icon-btn svg {
    width: 1.1rem;
    height: 1.1rem;
}

/* テーマに応じて太陽/月を出し分け */
.icon-sun {
    display: none;
}
[data-theme="dark"] .icon-sun {
    display: block;
}
[data-theme="dark"] .icon-moon {
    display: none;
}

.burger {
    display: inline-flex;
}

@media (min-width: 900px) {
    .burger {
        display: none;
    }
}

/* --- Mobile drawer ---------------------------------------- */

.drawer {
    position: fixed;
    inset: 0;
    z-index: 99;
    background: var(--bg-main);
    display: flex;
    flex-direction: column;
    justify-content: center;
    padding: 2rem 1.5rem;
    opacity: 0;
    visibility: hidden;
    transition:
        opacity 0.4s ease,
        visibility 0.4s ease;
}

.drawer.is-open {
    opacity: 1;
    visibility: visible;
}

.drawer__link {
    display: block;
    font-size: 2rem;
    line-height: 1.4;
    letter-spacing: 0;
    color: var(--text-main);
    padding-block: 0.5rem;
    opacity: 0;
    transform: translateY(12px);
}

.drawer.is-open .drawer__link {
    animation: drawer-in 0.5s cubic-bezier(0.22, 1, 0.36, 1) forwards;
}

.drawer__link small {
    display: block;
    font-size: 0.7rem;
    letter-spacing: 0.15em;
    text-transform: uppercase;
    color: var(--text-sub);
    margin-top: -0.25rem;
}

@keyframes drawer-in {
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* --- Footer ----------------------------------------------- */

.site-footer {
    position: relative;
    z-index: 2;
    border-top: 1px solid var(--glass-border);
    padding-block: 4rem 2.5rem;
    margin-top: 2rem;
}

.site-footer__grid {
    display: grid;
    gap: 3rem;
}

@media (min-width: 768px) {
    .site-footer__grid {
        grid-template-columns: 1fr auto;
        gap: 4rem;
    }
}

.footer-nav {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 0.75rem 2rem;
}

@media (min-width: 640px) {
    .footer-nav {
        grid-template-columns: repeat(3, minmax(0, 1fr));
    }
}

.footer-nav a {
    font-size: 0.8125rem;
    letter-spacing: 0.02em;
    color: var(--text-sub);
    transition: color 0.3s ease;
}

.footer-nav a:hover {
    color: var(--text-main);
}

.site-footer__meta {
    margin-top: 3rem;
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
    justify-content: flex-end;
    align-items: center;
    font-size: 0.7rem;
    letter-spacing: 0.1em;
    color: var(--text-sub);
}

/* --- Button ----------------------------------------------- */

.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.75rem;
    padding: 1rem 2rem;
    border: 1px solid var(--glass-border);
    border-radius: 999px;
    font-size: 0.8125rem;
    letter-spacing: 0.04em;
    color: var(--text-main);
    transition:
        background-color 0.3s ease,
        color 0.3s ease,
        border-color 0.3s ease;
}

.btn:hover {
    background: var(--text-main);
    color: var(--bg-main);
    border-color: var(--text-main);
}

.btn__arrow {
    transition: transform 0.3s cubic-bezier(0.22, 1, 0.36, 1);
}

.btn:hover .btn__arrow {
    transform: translateX(4px);
}