/* 1) Registra a “fonte” com o SVG da pista */
@font-face {
  font-family: 'RacetrackIcon';
  src: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 512 512'><path d='M30 300 C0 10, 80 40, 130 35 C180 600, 500 20, 480 385 C500 700, 376 200, 300 400 C360 320, 0 800, 27 130' fill='none' stroke='currentColor' stroke-width='40' stroke-linecap='round' stroke-linejoin='round'/></svg>") format('svg');
  font-weight: normal;
  font-style: normal;
}

/* 2) Classe para renderizar o ícone */
.fa-racetrack {
  font-family: 'RacetrackIcon';
  /* controle o tamanho aqui: */
  font-size: inherit;           /* 2× o tamanho da fonte corrente */
  width: 1em;
  height: 1em;
  display: inline-block;

  /* aplica o SVG como máscara */
  -webkit-mask: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 512 512'><path d='M30 300 C0 10, 80 40, 130 35 C180 600, 500 20, 480 385 C500 700, 376 200, 300 400 C360 320, 0 800, 27 130' fill='none' stroke='currentColor' stroke-width='40' stroke-linecap='round' stroke-linejoin='round'/></svg>") no-repeat 50% 50%;
  mask:         url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 512 512'><path d='M30 300 C0 10, 80 40, 130 35 C180 600, 500 20, 480 385 C500 700, 376 200, 300 400 C360 320, 0 800, 27 130' fill='none' stroke='currentColor' stroke-width='40' stroke-linecap='round' stroke-linejoin='round'/></svg>") no-repeat 50% 50%;

  -webkit-mask-size: contain;
  mask-size: contain;

  /* a cor do ícone herda de “color:” no elemento pai */
  background-color: currentColor;
}