04Half-circle gauge

<main class="stage">
  <div class="gauge is-demo" role="progressbar" aria-valuemin="0" aria-valuemax="100" aria-valuenow="76" aria-label="Speed">
    <span class="gauge__needle"></span>
  </div>
  <p class="cap">Speed</p>
</main>

@use "../../../../site/static/demo-tokens" as *;

// ── 변수 3개 ──────────────────────────────────────────
$duration: $dur-loop;                             // 바늘이 왼쪽 끝에서 오른쪽 끝까지 도는 시간
$easing: $ease-out;
$color: $subject-blue;                            // 채워진 구간 색

@include stage($stage-paper);

// 채움 각도와 바늘 각도를 같은 값으로 구동한다. ::before·바늘 둘 다 자식이라 inherits 가 필요하다
@property --percent {
  syntax: "<number>";
  inherits: true;
  initial-value: 0;
}

.gauge {
  --percent: 0;
  position: relative;
  width: clamp(140px, 38vw, 170px);
  height: clamp(70px, 19vw, 85px);                // 폭의 절반 — 원 아래쪽 절반을 overflow 로 자른다
  overflow: hidden;
}
.gauge::before {
  content: "";
  position: absolute;
  top: 0; left: 0;
  width: 100%;
  height: 200%;                                   // 부모 높이의 두 배 = 완전한 원. 위쪽 절반만 보인다
  border-radius: 50%;
  background: conic-gradient(from -90deg, $color calc(var(--percent) * 1.8deg), rgba($subject-ink, .12) 0);
}
.gauge__needle {
  position: absolute;
  bottom: 0;
  left: 50%;
  width: 3px;
  height: calc(100% - 6px);
  background: $subject-ink;
  border-radius: 2px;
  transform-origin: bottom center; // 규칙8: 바늘 회전 피벗
  transform: translateX(-50%) rotate(calc(var(--percent) * 1.8deg - 90deg));
}
.gauge.is-demo { animation: sweep $duration $easing infinite; }

@keyframes sweep { 0% { --percent: 0; } 100% { --percent: 100; } }

.cap {
  margin: 14px 0 0;
  color: $subject-ink;
  font: 600 clamp(12px, 3.2vw, 14px)/1 -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
}

@media (prefers-reduced-motion: reduce) {
  .gauge.is-demo { animation: none; --percent: 76; }
}

html, body {
  margin: 0;
  overflow: hidden;
}

.stage {
  box-sizing: border-box;
  min-height: 100vh;
  display: grid;
  place-items: center;
  margin: 0;
  background: #ffffff;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

@property --percent {
  syntax: "<number>";
  inherits: true;
  initial-value: 0;
}
.gauge {
  --percent: 0;
  position: relative;
  width: clamp(140px, 38vw, 170px);
  height: clamp(70px, 19vw, 85px);
  overflow: hidden;
}

.gauge::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 200%;
  border-radius: 50%;
  background: conic-gradient(from -90deg, #2f6df6 calc(var(--percent) * 1.8deg), rgba(23, 20, 26, 0.12) 0);
}

.gauge__needle {
  position: absolute;
  bottom: 0;
  left: 50%;
  width: 3px;
  height: calc(100% - 6px);
  background: #17141a;
  border-radius: 2px;
  transform-origin: bottom center;
  transform: translateX(-50%) rotate(calc(var(--percent) * 1.8deg - 90deg));
}

.gauge.is-demo {
  animation: sweep 2s ease-out infinite;
}

@keyframes sweep {
  0% {
    --percent: 0;
  }
  100% {
    --percent: 100;
  }
}
.cap {
  margin: 14px 0 0;
  color: #17141a;
  font: 600 clamp(12px, 3.2vw, 14px)/1 -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
}

@media (prefers-reduced-motion: reduce) {
  .gauge.is-demo {
    animation: none;
    --percent: 76;
  }
}

import type { CSSProperties } from "react";
import styles from "./HalfGauge.module.scss";

export type HalfGaugeProps = {
  /** 0~100 */
  percent: number;
  duration?: number;
  easing?: string;
  color?: string;
  label?: string;
};

type Vars = CSSProperties & {
  "--duration"?: string;
  "--easing"?: string;
  "--percent"?: number;
};

export default function HalfGauge({
  percent,
  duration = 600,
  easing = "ease-out",
  color = "#2f6df6",
  label,
}: HalfGaugeProps) {
  const p = Math.max(0, Math.min(100, percent));
  const vars: Vars = { "--duration": `${duration}ms`, "--easing": easing, "--color": color, "--percent": p };

  return (
    <div
      className={styles.gauge}
      style={vars}
      role="progressbar"
      aria-valuemin={0}
      aria-valuemax={100}
      aria-valuenow={p}
      aria-label={label}
    >
      <span className={styles.needle} />
    </div>
  );
}