* { box-sizing: border-box; }

body {
    font-family: Arial, Helvetica, sans-serif;
    background: #ffffff;
    color: #111111;
    margin: 0;
    padding: 40px 20px;
    text-align: center;
}

h1 { font-size: 28px; margin-bottom: 4px; }
h2 { font-size: 18px; font-weight: normal; color: #555; margin-top: 0; }

.disclaimer {
    max-width: 680px;
    margin: 16px auto 30px;
    padding: 12px 18px;
    background: #fff8e1;
    border: 1px solid #f0d878;
    border-radius: 6px;
    font-size: 14px;
    color: #6b5900;
    text-align: left;
}

nav a {
    display: inline-block;
    margin: 10px;
    padding: 12px 24px;
    background: #2456c9;
    color: #fff;
    text-decoration: none;
    border-radius: 6px;
    font-size: 16px;
}
nav a:hover { background: #1a3f9e; }

.back {
    display: inline-block;
    margin-top: 30px;
    color: #2456c9;
}

/* --- Snellen chart --- */
.calibration {
    max-width: 500px;
    margin: 0 auto 40px;
    font-size: 14px;
    text-align: left;
    background: #f2f5fb;
    border: 1px solid #cdd8ef;
    border-radius: 6px;
    padding: 14px 18px;
}
.calibration .card {
    width: 8.56cm;
    height: 5.4cm;
    border: 2px dashed #2456c9;
    border-radius: 8px;
    margin: 10px auto;
    display: flex;
    align-items: center;
    justify-content: center;
    color: #2456c9;
    font-size: 13px;
}

.chart { max-width: 900px; margin: 0 auto; }
.row {
    display: flex;
    justify-content: center;
    align-items: baseline;
    gap: 0.35em;
    line-height: 1;
    margin: 0.5em 0;
    font-family: "Liberation Sans", Arial, Helvetica, sans-serif;
    font-weight: 700;
    letter-spacing: 0.15em;
}
.row .label {
    font-family: Arial, sans-serif;
    font-weight: normal;
    font-size: 13px;
    letter-spacing: normal;
    color: #888;
    width: 70px;
    text-align: right;
    margin-right: 14px;
}

/* --- Ishihara plates --- */
.plates {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 24px;
    max-width: 950px;
    margin: 0 auto;
}
.plate {
    background: #fff;
}
.plate img {
    width: 220px;
    height: 220px;
    border-radius: 50%;
    display: block;
}
.plate p {
    margin-top: 8px;
    font-size: 13px;
    color: #666;
}