:root {
    --background: #333;
    --subtext: #ccc;
    --text: #fff;
}

* {
    box-sizing: border-box;
    padding: 0;
    margin: 0;
}

html,
body {
    margin: 0;
    background: var(--background);
    font-family: monospace, sans-serif;
    overflow: hidden;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    user-select: none;
    font-size: 16px;
}

#breadcrumb {
    z-index: 1000;
    text-align: center;
    background-color: #111;
    color: var(--subtext);
    position: relative;
}

#breadcrumb i {
    color: #777;
    margin: 0 3px;
}

.card {
    position: absolute;
    width: 100%;
    height: 100vh;
    opacity: 0;
    transition: transform 0.3s ease, opacity 0.3s ease;
}

.card h2 {
    margin: 1rem 2rem;
    padding: 2rem;
    font-size: 2rem;
    color: var(--text);
    font-weight: 500;
}

.card article {
    margin: 0 2rem;
    padding: 0 2rem;
    font-size: 1.2rem;
    line-height: 1.5;
    color: var(--subtext);
}

.card.active {
    position: relative;
    opacity: 1;
    transform: translateX(0);
}

.slide-left {
    transform: translateX(-200%);
}
.slide-right {
    transform: translateX(200%);
}
.slide-up {
    transform: translateY(-200%);
}
.slide-down {
    transform: translateY(200%);
}

nav {
    z-index: 999;
    background: #111;
    color: var(--text);
    padding: 10px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

nav .group {
    display: flex;
    gap: 10px;
}

nav button {
    padding: 10px 20px;
    background: #333;
    color: var(--text);
    border: none;
    cursor: pointer;
    font-size: inherit;
    font-family: inherit;
    border-radius: 10px;
}

nav button:hover {
    background: #555;
}

nav button:disabled {
    opacity: 0.3;
    cursor: not-allowed;
}

@media screen and (min-width: 900px) {
    #breadcrumb {
        position: absolute;
        top: 1rem;
        left: 50%;
        transform: translateX(-50%);
        background-color: transparent;
    }
}

@media screen and (max-width: 900px) {
    nav {
        display: none !important;
    }
    #breadcrumb {
        font-size: 12px;
        padding: 6px;
    }
    .card h2 {
        padding: 0 1rem;
        font-size: 1.5rem;
        margin-top: 3rem;
    }
    .card article {
        padding: 1rem;
        font-size: 1rem;
    }
}