:root {
    --bg-color: #141526;
    --panel-bg: #1e1f36;
    --text-main: #ffffff;
    --text-muted: #8b949e;
    --color-dl: #00e5ff;
    --color-ul: #b000ff;
    --color-ping: #ffcc00;
}

* { margin: 0; padding: 0; box-sizing: border-box; font-family: 'Segoe UI', Roboto, Helvetica, Arial, sans-serif; }

body {
    background-color: var(--bg-color);
    color: var(--text-main);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
    overflow: hidden;
}

.app-container { width: 100%; max-width: 800px; padding: 2rem; display: flex; flex-direction: column; align-items: center; }
.title { margin-bottom: 2rem; color: var(--text-muted); font-weight: 400; text-align: center; }

.metrics-bar { display: flex; justify-content: space-between; width: 100%; max-width: 500px; margin-bottom: 3rem; opacity: 0; transform: translateY(-20px); transition: all 0.5s ease; }
.metrics-bar.visible { opacity: 1; transform: translateY(0); }
.metric { text-align: center; }
.metric-label { font-size: 0.85rem; color: var(--text-muted); text-transform: uppercase; letter-spacing: 1px; margin-bottom: 5px; display: flex; align-items: center; justify-content: center; gap: 5px; }
.metric-value { font-size: 1.8rem; font-weight: 300; }
.metric-unit { font-size: 0.9rem; color: var(--text-muted); }

.icon-ping { color: var(--color-ping); }
.icon-dl { color: var(--color-dl); }
.icon-ul { color: var(--color-ul); }

.gauge-container { position: relative; width: 300px; height: 300px; display: flex; justify-content: center; align-items: center; }
.gauge-svg { position: absolute; width: 100%; height: 100%; transform: rotate(-135deg); }
.gauge-bg { fill: none; stroke: #2a2b4a; stroke-width: 12; stroke-linecap: round; stroke-dasharray: 628; stroke-dashoffset: 157; }
.gauge-progress { fill: none; stroke: var(--color-dl); stroke-width: 12; stroke-linecap: round; stroke-dasharray: 628; stroke-dashoffset: 628; transition: stroke-dashoffset 0.1s linear, stroke 0.5s ease; filter: drop-shadow(0 0 8px var(--color-dl)); }

.gauge-center { text-align: center; z-index: 10; display: none; flex-direction: column; }
.current-speed { font-size: 4rem; font-weight: 200; line-height: 1; margin-bottom: 5px; }
.current-unit { font-size: 1.2rem; color: var(--text-muted); }
.current-label { font-size: 1rem; font-weight: bold; text-transform: uppercase; letter-spacing: 2px; margin-top: 10px; color: var(--color-dl); transition: color 0.5s ease; }

.btn-start { position: absolute; width: 150px; height: 150px; border-radius: 50%; background: transparent; border: 2px solid var(--color-dl); color: var(--color-dl); font-size: 1.8rem; font-weight: 300; cursor: pointer; display: flex; justify-content: center; align-items: center; transition: all 0.3s ease; box-shadow: 0 0 20px rgba(0, 229, 255, 0.2) inset, 0 0 20px rgba(0, 229, 255, 0.2); z-index: 20; }
.btn-start:hover { background: rgba(0, 229, 255, 0.1); box-shadow: 0 0 30px rgba(0, 229, 255, 0.4) inset, 0 0 30px rgba(0, 229, 255, 0.4); transform: scale(1.05); }
.btn-start::before { content: ''; position: absolute; width: 100%; height: 100%; border-radius: 50%; border: 1px solid var(--color-dl); animation: pulseRing 2s infinite; }

@keyframes pulseRing { 0% { transform: scale(1); opacity: 1; } 100% { transform: scale(1.5); opacity: 0; } }