/* Container for the button groups */
.activity-group {
    background-color: #eefbf9; /* A very light version of your teal */
    padding: 2rem;
    border-radius: 12px;
    height: 100%; /* Ensures columns match height */
    box-sizing: border-box;
    display: flex;
    flex-direction: column;
    justify-content: center;
    box-shadow: 0 4px 6px rgba(0,0,0,0.05);
}

/* The Buttons themselves */
.activity-btn {
    display: block;
    width: 100%;
    padding: 15px 0;
    margin-bottom: 15px;

    /* Typography */
    font-family: 'Raleway', sans-serif;
    font-weight: 600;
    text-align: center;
    text-decoration: none;
    text-transform: uppercase;
    letter-spacing: 1.5px;
    font-size: 0.9rem;

    /* Color & Border */
    background-color: #ffffff;
    color: #a4243b; /* Your Brand Red */
    border: 2px solid #a4243b;
    border-radius: 6px;

    /* Animation */
    transition: all 0.3s ease;
    cursor: pointer;
}

/* Hover Effect */
.activity-btn:hover {
    background-color: #a4243b;
    color: #ffffff;
    transform: translateY(-3px); /* Lifts up slightly */
    box-shadow: 0 5px 15px rgba(164, 36, 59, 0.2);
}

/* Remove margin from the last button in a group */
.activity-btn:last-child {
    margin-bottom: 0;
}

/* Style for the Adventure Image container */
.adventure-img-container {
    position: relative;
    overflow: hidden;
    border-radius: 12px;
    box-shadow: 0 10px 20px rgba(0,0,0,0.1);
}

.adventure-img-container img {
    width: 100%;
    height: auto;
    display: block;
    transition: transform 0.5s ease;
}

.adventure-img-container:hover img {
    transform: scale(1.05); /* Zoom effect on hover */
}

.adventure-title {
    position: absolute;
    bottom: 20px;
    left: 20px;
    color: white;
    margin: 0;
    background: rgba(164, 36, 59, 0.9); /* Brand Red with transparency */
    padding: 5px 15px;
    border-radius: 4px;
}
2. The HTML
Replace the entire <div class="row" style="margin-top:4%"> block at the bottom of your page with this cleaner version. I have removed the "Spacer" headers and the messy inline styling.

HTML

<div class="row" style="margin-top:4%">

    <div class="one-third column">
        <a href="content-template.html" style="text-decoration:none;">
            <div class="adventure-img-container">
                <img src="images/mtn.jpg" alt="Adventure">
                <h3 class="adventure-title">Adventure</h3>
            </div>
        </a>
    </div>

    <div class="one-third column">
        <div class="activity-group">
            <a href="content-SUP-packed-list.html" class="activity-btn">SUP</a>
            <a href="content-sailing-packed-list.html" class="activity-btn">Dinghy</a>
        </div>
    </div>

    <div class="one-third column">
        <div class="activity-group">
            <a href="content-our-beach-holiday.html" class="activity-btn">Beach</a>
            <a href="content-skiing2.html" class="activity-btn">Skiing</a>
        </div>
    </div>

</div>