:root {
    --bg: #0f0f0f;
    --panel: #171717;
    --panel-soft: #1f1f1f;
    --text: #e0e0e0;
    --muted: #8a8a8a;
    --line: #2c2c2c;
    --blue: #4a9eff;
    --green: #22c55e;
    --yellow: #f59e0b;
    --red: #ef4444;
    --orange: #fb923c;
    --radius: 22px;
}

* {
    box-sizing: border-box;
}

html {
    min-height: 100%;
    background: var(--bg);
}

body {
    margin: 0;
    min-height: 100%;
    background:
        radial-gradient(circle at top left, rgba(74, 158, 255, 0.12), transparent 32rem),
        radial-gradient(circle at bottom right, rgba(34, 197, 94, 0.08), transparent 30rem),
        var(--bg);
    color: var(--text);
    font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
}

button,
select {
    font: inherit;
}

button {
    cursor: pointer;
}

.app {
    width: min(1180px, calc(100% - 32px));
    margin: 0 auto;
    padding: 28px 0 56px;
}

.topbar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 18px;
    margin-bottom: 70px;
}

.brand {
    display: flex;
    align-items: center;
    gap: 14px;
}

.brand-mark {
    width: 14px;
    height: 14px;
    border-radius: 999px;
    background: var(--blue);
    box-shadow: 0 0 32px rgba(74, 158, 255, 0.75);
}

.brand-title {
    font-size: 16px;
    font-weight: 650;
    letter-spacing: 0.01em;
}

.brand-subtitle {
    margin-top: 2px;
    color: var(--muted);
    font-size: 13px;
}

.screen {
    display: none;
}

.screen.active {
    display: block;
}

.hero {
    max-width: 760px;
    padding: 82px 0 40px;
}

.eyebrow {
    margin: 0 0 14px;
    color: var(--blue);
    font-size: 13px;
    font-weight: 650;
    letter-spacing: 0.11em;
    text-transform: uppercase;
}

h1,
h2,
h3,
p {
    margin-top: 0;
}

h1 {
    margin-bottom: 22px;
    font-size: clamp(44px, 8vw, 92px);
    line-height: 0.94;
    letter-spacing: -0.07em;
}

h2 {
    margin-bottom: 0;
    font-size: clamp(30px, 5vw, 52px);
    line-height: 1;
    letter-spacing: -0.05em;
}

.lead {
    max-width: 650px;
    margin-bottom: 36px;
    color: #b8b8b8;
    font-size: clamp(18px, 2vw, 22px);
    line-height: 1.55;
}

.duration-box {
    display: flex;
    align-items: center;
    gap: 14px;
    margin-bottom: 24px;
    flex-wrap: wrap;
}

.duration-box label {
    color: var(--muted);
    font-size: 14px;
}

select {
    min-width: 160px;
    padding: 12px 16px;
    border: 1px solid var(--line);
    border-radius: 14px;
    background: var(--panel);
    color: var(--text);
    outline: none;
}

.primary-button,
.ghost-button,
.danger-button {
    border: 1px solid transparent;
    border-radius: 999px;
    padding: 13px 22px;
    color: var(--text);
    transition: transform 0.15s ease, border-color 0.15s ease, background 0.15s ease;
}

.primary-button {
    background: var(--blue);
    color: #06111f;
    font-weight: 700;
}

.primary-button.small {
    padding: 11px 18px;
}

.ghost-button {
    background: rgba(255,255,255,0.03);
    border-color: var(--line);
}

.danger-button {
    background: rgba(239, 68, 68, 0.1);
    border-color: rgba(239, 68, 68, 0.4);
    color: #fecaca;
}

.primary-button:hover,
.ghost-button:hover,
.danger-button:hover {
    transform: translateY(-1px);
}

.section-head {
    display: flex;
    align-items: flex-end;
    justify-content: space-between;
    gap: 24px;
    margin-bottom: 26px;
}

.test-actions {
    display: flex;
    align-items: center;
    justify-content: flex-end;
    gap: 12px;
    flex-wrap: wrap;
}

.timer {
    min-width: 92px;
    padding: 10px 14px;
    border: 1px solid var(--line);
    border-radius: 999px;
    color: var(--muted);
    text-align: center;
    font-variant-numeric: tabular-nums;
}

.metrics-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 14px;
    margin-bottom: 18px;
}

.metric-card,
.summary-item,
.result-score {
    border: 1px solid var(--line);
    border-radius: var(--radius);
    background: rgba(23, 23, 23, 0.82);
    backdrop-filter: blur(12px);
}

.metric-card {
    padding: 22px;
    min-height: 150px;
}

.metric-card span,
.summary-item span,
.result-score span {
    display: block;
    margin-bottom: 16px;
    color: var(--muted);
    font-size: 13px;
}

.metric-card strong {
    display: inline-block;
    font-size: clamp(38px, 6vw, 64px);
    line-height: 0.95;
    letter-spacing: -0.06em;
    font-variant-numeric: tabular-nums;
}

.metric-card small {
    color: var(--muted);
    font-size: 14px;
}

.metric-card.good strong {
    color: var(--green);
}

.metric-card.warn strong {
    color: var(--yellow);
}

.metric-card.bad strong {
    color: var(--red);
}

.chart-shell {
    width: 100%;
    height: 410px;
    padding: 18px;
    border: 1px solid var(--line);
    border-radius: var(--radius);
    background: rgba(23, 23, 23, 0.74);
}

.live-report,
.report {
    margin-top: 18px;
    padding: 22px;
    border: 1px solid var(--line);
    border-radius: var(--radius);
    background: rgba(23, 23, 23, 0.7);
    color: #cfcfcf;
    line-height: 1.65;
}

.report h3 {
    margin-bottom: 12px;
    font-size: 22px;
}

.report ul {
    margin: 0;
    padding-left: 20px;
}

.report li + li {
    margin-top: 8px;
}

.result-score {
    display: flex;
    align-items: flex-end;
    justify-content: space-between;
    gap: 18px;
    margin-bottom: 18px;
    padding: 28px;
}

.result-score strong {
    display: block;
    font-size: clamp(64px, 10vw, 126px);
    line-height: 0.9;
    letter-spacing: -0.08em;
}

.result-score p {
    max-width: 420px;
    margin: 0;
    color: #b8b8b8;
    font-size: 18px;
    line-height: 1.45;
}

.summary-grid {
    display: grid;
    grid-template-columns: repeat(7, 1fr);
    gap: 12px;
    margin-bottom: 18px;
}

.summary-item {
    padding: 18px;
}

.summary-item strong {
    display: block;
    font-size: 24px;
    letter-spacing: -0.04em;
    font-variant-numeric: tabular-nums;
}

.info-panel {
    display: none;
    margin-top: 40px;
    padding: 28px;
    border: 1px solid var(--line);
    border-radius: var(--radius);
    background: rgba(23, 23, 23, 0.72);
}

.info-panel.active {
    display: block;
}

.terms-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 22px;
    margin-top: 26px;
}

.terms-grid h3 {
    margin-bottom: 8px;
    color: var(--text);
    font-size: 18px;
}

.terms-grid p {
    margin-bottom: 0;
    color: #a9a9a9;
    line-height: 1.55;
}

@media (max-width: 980px) {
    .metrics-grid,
    .summary-grid,
    .terms-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .section-head,
    .result-score {
        align-items: flex-start;
        flex-direction: column;
    }
}

@media (max-width: 620px) {
    .app {
        width: min(100% - 22px, 1180px);
        padding-top: 18px;
    }

    .topbar {
        align-items: flex-start;
        margin-bottom: 42px;
        flex-direction: column;
    }

    .hero {
        padding-top: 38px;
    }

    .metrics-grid,
    .summary-grid,
    .terms-grid {
        grid-template-columns: 1fr;
    }

    .chart-shell {
        height: 330px;
        padding: 12px;
    }

    .test-actions {
        justify-content: flex-start;
    }

    .primary-button,
    .ghost-button,
    .danger-button {
        width: 100%;
    }

    .timer {
        width: 100%;
    }
}