html, body {
    height: 100%;
    margin: 0;
    padding: 0;
}
body {
    min-height: 100vh;
    width: 100vw;
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    /* Animirani gradient stvarno CRVENA-NARANČASTA-ŽUTA */
    background: linear-gradient(-45deg, #ff7477, #ffb347, #fff176, #ff7e5f, #ffae42, #ffe259, #ff6e7f, #ffae42);
    background-size: 400% 400%;
    animation: bgmove 14s ease-in-out infinite;
    display: flex;
    align-items: center;
    justify-content: center;
}

@keyframes bgmove {
    0% {
        background-position: 0% 70%;
    }
    40% {
        background-position: 100% 50%;
    }
    60% {
        background-position: 70% 100%;
    }
    100% {
        background-position: 0% 70%;
    }
}

.center-box {
    background: rgba(255,255,255,0.98);
    border-radius: 18px;
    box-shadow: 0 4px 20px 0 rgba(255,164,50,0.13);
    max-width: 370px;
    width: 94vw;
    padding: 32px 19px 26px 19px;
    display: flex;
    flex-direction: column;
    align-items: stretch;
    gap: 19px;
}

h1 {
    color: #cf2727;
    font-size: 1.53em;
    margin: 0 0 0.5em 0;
    font-weight: 700;
    letter-spacing: 0.043em;
    text-align: center;
}

p, label, b, strong {
    color: #1d1d1d;
    font-size: 1.08em;
    margin: 0;
    font-weight: 500;
    text-align: center;
}

form {
    display: flex;
    flex-direction: column;
    align-items: stretch;
    gap: 12px;
    margin-top: 0;
}

label {
    font-weight: 600;
    margin-bottom: 4px;
    font-size: 1.07em;
}

input[type="number"] {
    width: 100%;
    padding: 12px;
    border-radius: 9px;
    border: 1.3px solid #ffae42;
    background: #fff;
    font-size: 1.09em;
    color: #252525;
    box-sizing: border-box;
    transition: border 0.18s;
    text-align: center;
}

input[type="number"]:focus {
    border: 1.5px solid #ff7e5f;
    outline: none;
}

/* Gumbi su uvijek jasno bijeli, tekst potpuno centriran! */
input[type="submit"], a.button-link {
    width: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    background: #fff;
    color: #d42525;
    border: 2px solid #ffae42;
    font-weight: 700;
    font-size: 1.12em;
    border-radius: 100px;
    padding: 15px 0;
    margin-top: 2px;
    box-shadow: 0 2px 9px 0 rgba(255,164,50,0.10);
    cursor: pointer;
    text-decoration: none;
    transition: background 0.19s, color 0.13s, border 0.13s;
    letter-spacing: 0.04em;
}

input[type="submit"]:hover, a.button-link:hover {
    background: #fff6e8;
    color: #e98029;
    border: 2px solid #ffb347;
}

a.return-link {
    display: block;
    margin: 13px auto 4px auto;
    color: #d8732a;
    text-decoration: underline;
    font-size: 1.06em;
    letter-spacing: 0.01em;
    font-weight: 500;
    transition: color 0.2s;
    text-align: center;
}
a.return-link:hover {
    color: #cf2727;
}

strong {
    color: #fff;
    background: #ffb347;
    border-radius: 11px;
    padding: 4px 16px;
    letter-spacing: 0.07em;
    font-size: 1.11em;
    text-align: center;
    display: inline-block;
    margin: 0.4em 0;
}

@media (max-width: 600px) {
    .center-box {
        padding: 13px 3vw 11px 3vw;
        max-width: 100vw;
        gap: 14px;
    }
    h1 {
        font-size: 1.15em;
    }
    form label, form input, input[type="submit"], a.button-link {
        font-size: 1em;
    }
}