.app-header,
.app-header * {
    box-sizing: border-box;
}

.app-header {
    position: fixed;
    top: 0;
    left: 0;
    z-index: 50;
    width: 100%;
    height: 72px;
    padding: 0 24px;
    border: 0;
    background: rgba(255, 255, 255, 0.8);
    box-shadow: 0 8px 32px rgba(31, 38, 135, 0.07);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    font-family: "Noto Sans JP", "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", "Hiragino Kaku Gothic ProN", Meiryo, sans-serif;
    font-size: 16px;
    line-height: 1.5;
}

.app-header__inner {
    width: min(72rem, 100%);
    height: 100%;
    margin: 0 auto;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
}

.app-header__brand {
    display: flex;
    align-items: center;
    gap: 8px;
    color: #1e293b;
    font-size: 20px;
    font-weight: 900;
    line-height: 1.2;
    letter-spacing: -0.025em;
    text-decoration: none;
    white-space: nowrap;
}

.app-header__actions {
    display: flex;
    align-items: center;
    gap: 16px;
}

.app-header__link {
    display: none;
    color: #475569;
    font-size: 14px;
    font-weight: 700;
    line-height: 1.2;
    text-decoration: none;
    transition: color 160ms ease;
    white-space: nowrap;
}

.app-header__link:hover {
    color: #16a34a;
}

.app-header__lang-switch {
    display: flex;
    align-items: center;
    overflow: hidden;
    border: 1px solid #e2e8f0;
    border-radius: 999px;
    background: #f1f5f9;
    font-size: 12px;
    font-weight: 700;
    line-height: 1;
}

.app-header__lang-link,
.app-header__lang-current {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 38px;
    padding: 9px 12px;
    text-decoration: none;
}

.app-header__lang-current {
    color: #1e293b;
    background: #ffffff;
    box-shadow: 0 1px 4px rgba(15, 23, 42, 0.08);
}

.app-header__lang-link {
    color: #64748b;
    transition: color 160ms ease, background 160ms ease;
}

.app-header__lang-link:hover {
    color: #1e293b;
    background: #ffffff;
}

.app-header__download {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 34px;
    padding: 8px 16px;
    border-radius: 999px;
    color: #ffffff;
    background: #16a34a;
    box-shadow: 0 10px 22px rgba(22, 163, 74, 0.2);
    font-size: 12px;
    font-weight: 700;
    line-height: 1.2;
    text-decoration: none;
    transition: background 160ms ease, transform 160ms ease;
    white-space: nowrap;
}

.app-header__download:hover {
    background: #15803d;
    transform: translateY(-1px);
}

@media (min-width: 640px) {
    .app-header__link {
        display: inline-flex;
    }
}

@media (max-width: 520px) {
    .app-header {
        height: 64px;
        padding: 0 12px;
    }

    .app-header__inner {
        gap: 10px;
    }

    .app-header__brand {
        max-width: 44vw;
        font-size: 14px;
        white-space: normal;
    }

    .app-header__actions {
        gap: 8px;
    }

    .app-header__lang-link,
    .app-header__lang-current {
        min-width: 32px;
        padding: 8px 9px;
    }

    .app-header__download {
        padding: 8px 12px;
    }
}