*,
*::before,
*::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}
:root {
    --bg: #fff;
    --text: #000;
    --text-secondary: #666;
    --text-tertiary: #999;
    --accent: #2563eb;
    --border: #e5e5e5;
    --header-h: 52px;
}
html {
    font-family: -apple-system, BlinkMacSystemFont, 'SF Pro Text', 'SF Pro Display',
        'Hiragino Kaku Gothic ProN', 'Hiragino Sans', Meiryo, sans-serif;
    font-size: 17px;
    line-height: 1.5;
    color: var(--text);
    background: var(--bg);
    -webkit-font-smoothing: antialiased;
}
body {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}
a {
    color: var(--accent);
    text-decoration: none;
}

.site-header {
    position: sticky;
    top: 0;
    z-index: 100;
    height: var(--header-h);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 24px;
    background: rgba(255, 255, 255, 0.85);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border);
}
.site-header-logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 16px;
    font-weight: 700;
    color: var(--text);
}
.site-header-logo:hover {
    text-decoration: none;
    opacity: 0.7;
}
.site-header-logo-icon {
    width: 30px;
    height: 30px;
    border-radius: 7px;
    background: var(--accent);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 13px;
    font-weight: 800;
    color: #fff;
}
.site-nav {
    display: flex;
    gap: 32px;
    list-style: none;
}
.site-nav a {
    font-size: 14px;
    color: var(--text-secondary);
    transition: color 0.15s;
}
.site-nav a:hover {
    color: var(--text);
    text-decoration: none;
}
.menu-toggle {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    color: var(--text);
    padding: 6px;
}
.menu-toggle svg {
    display: block;
}

.site-footer {
    padding: 28px 24px;
    border-top: 1px solid var(--border);
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 13px;
    color: var(--text-tertiary);
}
.site-footer a {
    color: var(--text-secondary);
    font-size: 13px;
}
.site-footer a:hover {
    color: var(--text);
}

@media (max-width: 640px) {
    .menu-toggle {
        display: flex;
        align-items: center;
        justify-content: center;
    }
    .site-nav {
        display: none;
        position: fixed;
        top: var(--header-h);
        left: 0;
        right: 0;
        bottom: 0;
        flex-direction: column;
        background: rgba(255, 255, 255, 0.98);
        backdrop-filter: blur(12px);
        -webkit-backdrop-filter: blur(12px);
        z-index: 99;
    }
    .site-nav.open {
        display: flex;
    }
    .site-nav a {
        display: block;
        padding: 18px 24px;
        font-size: 17px;
        color: var(--text);
    }
    .site-footer {
        flex-direction: column;
        gap: 8px;
        text-align: center;
    }
}