/* =============================================
   Gain Knowledge - Common CSS
   対象: 全ページ共通（ヘッダー・フッター・ベース）
   ============================================= */


/* -----------------------------------------------
   リセット & ベース
----------------------------------------------- */
.gk-page *,
.gk-page *::before,
.gk-page *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

.gk-page {
    font-family: 'Noto Sans JP', sans-serif;
    background: #050d1a;
    color: #e8f0fe;
    overflow-x: hidden;
    line-height: 1;
}

/* Astraテーマのデフォルトスタイルを上書き */
.gk-page a {
    text-decoration: none;
    color: inherit;
}

/* -----------------------------------------------
   ナビゲーション
----------------------------------------------- */
.gk-nav {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 16px 60px;
    border-bottom: 1px solid rgba(100, 160, 255, 0.1);
    background: rgba(5, 13, 26, 0.92);
    backdrop-filter: blur(14px);
    -webkit-backdrop-filter: blur(14px);
    position: sticky;
    top: 0;
    z-index: 100;
}

.gk-logo {
    display: flex;
    align-items: center;
    gap: 10px;
    text-decoration: none;
}

.gk-logo-mark {
    width: 38px;
    height: 38px;
    border-radius: 8px;
    background: linear-gradient(135deg, #4fa3ff 0%, #0040cc 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    font-family: 'Syne', sans-serif;
    font-weight: 800;
    font-size: 15px;
    color: #fff;
    letter-spacing: -1px;
    flex-shrink: 0;
}

.gk-logo-name {
    font-family: 'Syne', sans-serif;
    font-weight: 700;
    font-size: 14px;
    color: #e8f0fe;
    display: block;
}

.gk-logo-sub {
    font-size: 9px;
    color: #4fa3ff;
    letter-spacing: 0.14em;
    text-transform: uppercase;
    display: block;
    margin-top: -1px;
}

.gk-nav-links {
    display: flex;
    gap: 30px;
    list-style: none;
}

.gk-nav-links a {
    font-size: 12px;
    color: #ffffff;
    letter-spacing: 0.07em;
    transition: color 0.2s;
}

.gk-nav-links a:hover {
    color: #4fa3ff;
}

.gk-nav-cta {
    background: linear-gradient(90deg, #1a6aff, #0040cc);
    color: #fff !important;
    font-size: 12px;
    font-weight: 700;
    padding: 10px 20px;
    border-radius: 6px;
    letter-spacing: 0.05em;
    transition: opacity 0.2s;
    white-space: nowrap;
}

.gk-nav-cta:hover {
    opacity: 0.85;
}

/* ハンバーガー（スマホ用） */
.gk-nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    cursor: pointer;
    padding: 4px;
    background: none;
    border: none;
}

.gk-nav-toggle span {
    display: block;
    width: 22px;
    height: 2px;
    background: #e8f0fe;
    border-radius: 2px;
    transition: transform 0.3s, opacity 0.3s;
}

.gk-nav-toggle.is-open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.gk-nav-toggle.is-open span:nth-child(2) { opacity: 0; }
.gk-nav-toggle.is-open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* -----------------------------------------------
   フッター
----------------------------------------------- */
.gk-footer {
    padding: 28px 60px;
    border-top: 1px solid rgba(79, 163, 255, 0.08);
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 12px;
}

.gk-footer-copy {
    font-size: 11px;
    color: #ffffff;
}

.gk-footer-links {
    display: flex;
    gap: 22px;
}

.gk-footer-links a {
    font-size: 11px;
    color: #ffffff;
    transition: color 0.2s;
}

.gk-footer-links a:hover {
    color: #4fa3ff;
}

/* -----------------------------------------------
   スクロールアニメーション（全ページ共通）
----------------------------------------------- */
.gk-fade-in {
    opacity: 0;
    transform: translateY(24px);
    transition: opacity 0.65s ease, transform 0.65s ease;
}

.gk-fade-in.is-visible {
    opacity: 1;
    transform: translateY(0);
}

.gk-fade-in-delay-1 { transition-delay: 0.1s; }
.gk-fade-in-delay-2 { transition-delay: 0.2s; }
.gk-fade-in-delay-3 { transition-delay: 0.3s; }

/* -----------------------------------------------
   レスポンシブ
----------------------------------------------- */

/* タブレット */
@media (max-width: 1024px) {
    .gk-nav    { padding: 14px 32px; }
    .gk-footer { padding: 24px 32px; }
}

/* スマホ */
@media (max-width: 768px) {
    .gk-nav {
        padding: 14px 20px;
        position: relative;
    }

    .gk-nav-links,
    .gk-nav-cta {
        display: none;
    }

    .gk-nav-links.is-open {
        display: flex;
        flex-direction: column;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: rgba(5, 13, 26, 0.97);
        padding: 20px 24px;
        gap: 16px;
        border-bottom: 1px solid rgba(79, 163, 255, 0.12);
        z-index: 99;
    }

    .gk-nav-links.is-open + .gk-nav-cta {
        display: block;
        margin: 0 24px 16px;
        text-align: center;
    }

    .gk-nav-toggle { display: flex; }

    .gk-footer {
        padding: 20px;
        flex-direction: column;
        align-items: center;
        text-align: center;
    }
}