:root { --bg: #14110e; --fg: #f3ece1; --accent: #b85c38; }
* { box-sizing: border-box; }
body { margin: 0; font-family: system-ui, sans-serif; background: var(--bg); color: var(--fg); }
#app { max-width: 640px; margin: 0 auto; min-height: 100dvh; display: flex; flex-direction: column; justify-content: center; padding: 1.5rem; text-align: center; }
.pantalla { display: flex; flex-direction: column; gap: 1rem; align-items: center; }
.oculta { display: none; }
h1 { font-size: 3rem; margin: 0; letter-spacing: 0.2em; }
#cronometro { font-size: 6rem; font-variant-numeric: tabular-nums; font-weight: 700; }
#ejercicio-actual { font-size: 2rem; margin: 0; }
button { font-size: 1.25rem; padding: 0.9rem 1.6rem; border: none; border-radius: 12px; background: var(--accent); color: #fff; cursor: pointer; }
button.secundario { background: #2a241e; color: var(--fg); }
.controles { display: flex; gap: 1rem; }
.opciones-feedback { display: flex; flex-direction: column; gap: 0.75rem; width: 100%; }