* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html,
body {
    width: 100%;
    min-height: 100%;
    font-family: Arial, Helvetica, sans-serif;
    background: #080808;
    color: #ffffff;
}

body {
    min-height: 100vh;
    overflow-x: hidden;
}

.background {
    position: fixed;
    inset: 0;
    width: 100%;
    height: 100%;
    background:
        radial-gradient(circle at center, #202020 0%, #0c0c0c 55%, #000000 100%);
    z-index: 0;
}

.overlay {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.18);
    z-index: 1;
}

.container {
    position: relative;
    z-index: 2;
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 20px;
}

.card {
    width: min(520px, 100%);
    padding: 38px 28px;
    text-align: center;
    border-radius: 24px;
    background: rgba(20, 20, 20, 0.82);
    border: 1px solid rgba(255, 255, 255, 0.10);
    box-shadow: 0 25px 80px rgba(0, 0, 0, 0.55);
    backdrop-filter: blur(14px);
}

.logo {
    font-size: 26px;
    font-weight: 800;
    letter-spacing: 5px;
    margin-bottom: 28px;
}

.speed-box {
    margin-bottom: 30px;
}

#speed {
    font-size: 72px;
    line-height: 1;
    font-weight: 800;
}

.unit {
    margin-top: 8px;
    font-size: 16px;
    opacity: 0.65;
}

.stats {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 10px;
    margin-bottom: 28px;
}

.stat {
    padding: 15px 8px;
    border-radius: 14px;
    background: rgba(255, 255, 255, 0.06);
}

.label {
    display: block;
    font-size: 10px;
    letter-spacing: 1px;
    opacity: 0.55;
    margin-bottom: 7px;
}

.value {
    font-size: 23px;
    font-weight: 700;
}

.small {
    font-size: 10px;
    opacity: 0.55;
    margin-left: 2px;
}

.test-info {
    margin-bottom: 18px;
}

#testType {
    font-size: 12px;
    font-weight: 700;
    letter-spacing: 2px;
    margin-bottom: 7px;
}

#status {
    font-size: 13px;
    opacity: 0.65;
}

.progress {
    width: 100%;
    height: 7px;
    background: rgba(255, 255, 255, 0.08);
    border-radius: 10px;
    overflow: hidden;
    margin-top: 20px;
}

#progressBar {
    width: 0%;
    height: 100%;
    background: #ffffff;
    transition: width 0.15s linear;
}

#progressText {
    margin-top: 8px;
    font-size: 11px;
    opacity: 0.5;
}

#startButton {
    width: 100%;
    margin-top: 25px;
    padding: 16px;
    border: 0;
    border-radius: 14px;
    background: #ffffff;
    color: #000000;
    font-size: 15px;
    font-weight: 800;
    letter-spacing: 1px;
    cursor: pointer;
    transition: transform 0.15s, opacity 0.15s;
}

#startButton:hover {
    transform: translateY(-1px);
}

#startButton:active {
    transform: translateY(1px);
}

#startButton:disabled {
    opacity: 0.45;
    cursor: not-allowed;
    transform: none;
}

@media (max-width: 480px) {
    .card {
        padding: 30px 18px;
    }

    #speed {
        font-size: 58px;
    }

    .value {
        font-size: 19px;
    }
}