01Thanh chạy đầy cơ bản

<main class="stage">
  <div class="track is-demo" role="progressbar" aria-valuemin="0" aria-valuemax="100" aria-valuenow="76" aria-label="Đang tải lên">
    <div class="bar"></div>
  </div>
  <p class="cap">Đang tải lên</p>
</main>

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

// ── 변수 3개. 변형은 이것만 바꾼다 ──────────────────────────
$duration: $dur-loop;                            // 0 → 목표값까지 차는 시간
$easing: $ease-out;
$color: $subject-cream;                          // 채워지는 색

@include stage($stage-ink);

// 값은 등록된 숫자 커스텀 속성으로 애니메이션한다 (scroll() 이 아니라 실제 진행률 숫자)
@property --percent {
  syntax: "<number>";
  inherits: true;                                  // .bar 가 부모 .track 의 애니메이션 값을 그대로 물려받는다
  initial-value: 0;
}

.track {
  --percent: 0;
  position: relative;
  width: clamp(200px, 58vw, 280px);
  height: 14px;
  border-radius: $r-pill;
  background: rgba(255, 255, 255, .16);
  overflow: hidden;
}
.bar {
  position: absolute;
  inset: 0;
  border-radius: inherit;
  background: $color;
  transform: scaleX(calc(var(--percent) / 100));   // width 대신 scaleX 로만 채운다
  transform-origin: left center;
}
.track.is-demo { animation: fill $duration $easing infinite; }

@keyframes fill {
  0%   { --percent: 0; }
  60%  { --percent: 76; }
  100% { --percent: 76; }
}

.cap {
  margin: 14px 0 0;
  color: rgba(255, 255, 255, .7);
  font: 600 clamp(12px, 3.2vw, 14px)/1 -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
}

// ── 접근성: 움직임 줄이기 설정이면 목표값에서 정지 ────────────
@media (prefers-reduced-motion: reduce) {
  .track.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: #17141a;
  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;
}
.track {
  --percent: 0;
  position: relative;
  width: clamp(200px, 58vw, 280px);
  height: 14px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.16);
  overflow: hidden;
}

.bar {
  position: absolute;
  inset: 0;
  border-radius: inherit;
  background: #fff7e6;
  transform: scaleX(calc(var(--percent) / 100));
  transform-origin: left center;
}

.track.is-demo {
  animation: fill 2s ease-out infinite;
}

@keyframes fill {
  0% {
    --percent: 0;
  }
  60% {
    --percent: 76;
  }
  100% {
    --percent: 76;
  }
}
.cap {
  margin: 14px 0 0;
  color: rgba(255, 255, 255, 0.7);
  font: 600 clamp(12px, 3.2vw, 14px)/1 -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
}

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

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

export type LinearFillBarProps = {
  /** 0~100. 실제 진행률 숫자 그대로 넘긴다 (스크롤이 아니다) */
  percent: number;
  duration?: number;
  easing?: string;
  color?: string;
  label?: string;
};

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

export default function LinearFillBar({
  percent,
  duration = 600,
  easing = "cubic-bezier(.2,.8,.2,1)",
  color = "#fff7e6",
  label,
}: LinearFillBarProps) {
  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.track}
      style={vars}
      role="progressbar"
      aria-valuemin={0}
      aria-valuemax={100}
      aria-valuenow={p}
      aria-label={label}
    >
      <div className={styles.bar} />
    </div>
  );
}