body {
    font-family: 'Arial', sans-serif;
    background-color: #f4f4f4;
    margin: 10px;
    padding: 10px;
    display: flex;
    justify-content: center;
}

.container {
    background: #fff;
    padding: 0px 20px 20px 20px;
    border-radius: 12px;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
    width: 100%;
    max-width: 800px;
    line-height: 1.6;
}

h2 {
    border-bottom: 2px solid #ddd;
    padding-bottom: 5px;
    margin-top: 20px;
}

p, li {
    font-size: 16px;
    margin-bottom: 10px;
}

a {
    color: #0969da;
    text-decoration: underline;
    text-underline-offset: .2rem;
}

ul, ol {
    padding-left: 20px;
}

li {
    margin-bottom: 5px;
}

sup {
    font-size: 0.8em;
}

#popup-wrapper {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.6);
    justify-content: center;
    align-items: center;
    z-index: 999;
}

#popup-wrapper.warning {
    color: #d33;
}

#popup-wrapper.ok {
    color: #155;
}

.popup {
    background: #fff;
    padding: 20px;
    width: 80%;
    max-width: 800px;
    margin: 10% auto;
    border-radius: 12px;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
    text-align: center;
    position: relative;
    cursor: default;
}

.popup-close {
    position: absolute;
    top: 10px;
    right: 10px;
    font-size: 18px;
    color: #555;
    cursor: pointer;
    transition: color 0.3s ease;
}

.popup-close:hover {
    color: #d33;
}

.nav-arrows {
    display: flex;
    justify-content: space-between;
    align-items: center;
    text-align: center;
}

.nav-arrows h1 {
    margin: 0;
}

.arrow {
    display: flex;
    align-items: center;
    justify-content: center;
    text-decoration: none;
    font-size: 1.5rem;
    color: #4A90E2;
    transition: transform 0.2s ease-in-out;
}

.arrow-symbol {
    font-size: 2.5rem;
    margin-top: -7px;
}

.arrow-text {
    font-size: 0.8rem;
    margin: 0 5px;
    opacity: 0.8;
}

.arrow:hover {
    color: #2d6ca2;
    transform: scale(1.1);
}

.arrow.left {
    margin-right: auto;
}

.arrow.right {
    margin-left: auto;
}

/* Mobile-friendly adjustments */
@media (max-width: 600px) {
    .container {
        width: 95%;
        padding: 15px;
    }
    h2 {
        font-size: 18px;
    }
    p, li {
        font-size: 14px;
    }
}