:root {
  /* Colors — Apple System Settings-style palette */
  --color-bg:             #FBFBFD;
  --color-surface:        #FFFFFF;
  --color-sidebar:        #F4F4F6;
  --color-sidebar-strong: #ECECEE;

  --color-text:           #1D1D1F;
  --color-text-secondary: #3A3A3C;
  --color-text-muted:     #6E6E73;
  --color-text-light:     #5b5b6a;

  --color-accent:         #0066CC;
  --color-accent-hover:   #0077ED;
  --color-accent-press:   #0055AA;
  --color-accent-tint:    rgba(0,102,204,0.10);
  --color-accent-tint-strong: rgba(0,102,204,0.16);

  --color-danger:         #D70015;
  --color-danger-hover:   #E10A1F;
  --color-success:        #1F7A1F;
  --color-warn:           #B36B00;

  --color-divider:        rgba(0,0,0,0.10);
  --color-divider-soft:   rgba(0,0,0,0.06);
  --color-divider-strong: rgba(0,0,0,0.14);

  --color-hover:          rgba(0,0,0,0.04);
  --color-press:          rgba(0,0,0,0.06);
  --color-selected:       rgba(0,102,204,0.10);

  --color-input-bg:           #FFFFFF;
  --color-input-border:        rgba(0,0,0,0.14);
  --color-input-border-strong: rgba(0,0,0,0.22);

  --color-flash-success-bg: #E6F4EA;
  --color-flash-success-fg: #1F5E2C;
  --color-flash-error-bg:   #FCEAEA;
  --color-flash-error-fg:   #9F1717;

  /* Progress bar gradient stops */
  --progress-track:     rgba(0,0,0,0.06);
  --progress-fill:      linear-gradient(90deg, #0066CC, #2E8AE6);
  --progress-fill-warn: linear-gradient(90deg, #C97A00, #E89A1A);
  --progress-fill-danger: linear-gradient(90deg, #B00020, #D70015);

  /* Radius */
  --radius-control: 7px;
  --radius-card:    12px;
  --radius-modal:   14px;
  --radius-pill:    980px;

  /* Shadows — soft, layered Apple style */
  --shadow-card:
    0 0 0 0.5px rgba(0,0,0,0.06),
    0 1px 2px rgba(0,0,0,0.04),
    0 8px 24px -8px rgba(0,0,0,0.08);
  --shadow-card-hover:
    0 0 0 0.5px rgba(0,0,0,0.08),
    0 2px 4px rgba(0,0,0,0.05),
    0 16px 36px -10px rgba(0,0,0,0.14);
  --shadow-modal:
    0 0 0 0.5px rgba(0,0,0,0.10),
    0 24px 60px rgba(0,0,0,0.25);
  --shadow-btn:
    0 1px 1px rgba(0,0,0,0.05),
    0 0.5px 0 rgba(255,255,255,0.10) inset;
  --shadow-focus:        0 0 0 3px rgba(0,102,204,0.20);

  /* Motion */
  --ease:        cubic-bezier(0.28, 0.11, 0.32, 1);
  --ease-out:    cubic-bezier(0.0, 0.0, 0.2, 1);
  --dur-fast:    140ms;
  --dur-base:    220ms;
  --dur-slow:    340ms;

  /* Typography */
  --font-text:    "SF Pro Text", -apple-system, BlinkMacSystemFont, "PingFang SC", "Helvetica Neue", "Microsoft YaHei", sans-serif;
  --font-display: "SF Pro Display", -apple-system, BlinkMacSystemFont, "PingFang SC", "Helvetica Neue", "Microsoft YaHei", sans-serif;
  --font-mono:    ui-monospace, "SF Mono", "JetBrains Mono", Menlo, Consolas, monospace;

  /* Spacing scale (4px grid) */
  --sp-1: 4px;
  --sp-2: 8px;
  --sp-3: 12px;
  --sp-4: 16px;
  --sp-5: 20px;
  --sp-6: 24px;
  --sp-7: 32px;
  --sp-8: 40px;
  --sp-9: 48px;
}