:root {
    --black: #0a0a0a;
    --black-hover: #1a1a1a;
    --gray: #6b6b6b;
}

/* Reset */
* {
    box-sizing: border-box;
    font-family: 'Instrument Sans', -apple-system, BlinkMacSystemFont, "Segoe UI",
    Roboto, Helvetica, Arial, sans-serif;
}

html, body {
    height: 100%;
    margin: 0;
}

body {
    background: #ffffff;
    color: #000000;
}

/* Center layout */
.center {
    height: 100%;
    display: grid;
    place-items: center;
    padding: 24px;
}

/* Remove card look */
.button-card {
    background: transparent;
    border: none;
    box-shadow: none;
    padding: 0;
    width: min(520px, 100%);
    text-align: center;
}

/* MAIN BUTTON – like "ADD TO CART" */
.big-btn {
    appearance: none;
    border: none;
    background: var(--black);
    color: #ffffff;

    font-size: 21px;
    font-weight: 700;
    text-transform: uppercase;

    padding: 20px 32px;
    border-radius: 14px;
    width: 100%;

    cursor: pointer;
    transition: background 0.15s ease, transform 0.05s ease;
}

.big-btn:hover {
    background: var(--black-hover);
}

.big-btn:active {
    transform: scale(0.985);
}

/* Text under button */
.small {
    margin-top: 14px;
    font-size: 14px;
    font-weight: 500;
    color: var(--gray);
}

/* Footer link */
.footer {
    position: fixed;
    left: 0;
    right: 0;
    bottom: 24px;
    display: flex;
    justify-content: center;
}

.footer a {
    color: #000000;
    text-decoration: underline;
    font-size: 14px;
    font-weight: 500;
}