@import url("https://fonts.googleapis.com/css2?family=Noto+Sans+JP");
:root {
    --violet: 73, 36, 127;
    --sidebar-padding: 10px;
    --header-height: 35px;
}

body {
    font-family: "Noto Sans JP", sans-serif;
    margin: 0;
    padding: 0;
}

.header-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 1200px;
    padding: 0 10px;
}

header {
    display: flex;
    height: var(--header-height);
    padding: 7.5px;
    background: rgb(var(--violet));
    color: #fff;
    text-align: center;
}

header h1 {
    margin: 0 0 5px 15px;
    text-align: left;
    font-size: 1.35em;
}

header nav {
    margin: auto 15px;
}

header nav a {
    padding: 10px;
    margin: 10px 0;
    transition: box-shadow 0.2s ease-in-out 0.05s;
    color: #fff;
    text-decoration: none;
    text-align: center;
}

header nav a:hover {
    box-shadow: inset 0 calc(var(--header-height) * -1.3) calc(var(--header-height) * 0.15) #ffffff55;
}

.toggle-btn {
    display: none;
}

.sidebar {
    display: none;
}

.overlay {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: #00000000;
    z-index: 999;
}

.container {
    width: 60%;
    margin: 0 auto;
    padding: 12.5px 20px;
    min-height: 100vh;
}

main {
    display: block;
    margin-left: 40px;
}

main a {
    color: rgb(var(--violet));
    transition: box-shadow 0.1s ease-in, color 0.1s ease-in;
}

main a:hover {
    box-shadow: inset 0 -24px 0 0 rgb(var(--violet)); 
    color: #fff!important;
    text-decoration: none!important;
}

footer {
    display: block;
    background: rgb(var(--violet));
    color: #fff;
    text-align: center;
    padding: 10px 0;
    bottom: 0;
    width: 100%;
    line-height: 0;
}

@media (max-width: 768px) {
    main {
        margin: auto;
    }

    header nav {
        display: none;
    }

    .toggle-btn {
        display: block;
        color: #fff;
        background: none;
        border: none;
        font-size: 20px;
    }

    .sidebar {
        display: block;
        position: absolute;
        top: 0;
        left: -165px;
        width: 165px;
        min-height: 100vh;
        padding-top: var(--header-height);
        color: white;
        background-color: #333333dd;
        border-radius: 6px;
        transition: left 0.4s ease-in-out 0.05s;
        z-index: 1000;
    }

    .sidebar nav a {
        display: block;
        padding: 10px;
        margin: 10px 0;
        color: white;
        transition: background-color 0.1s ease-in-out 0.05s;
        text-decoration: none;
        text-align: center;
    }

    .sidebar nav a:hover {
        background-color: #ffffff55;
    }

    .sidebar.active {
        left: 0;
    }

    .sidebar.active + .overlay {
        display: block;
    }

    .container {
        width: 80%;
    }
}