Os icones do menu não aparecem para mim | CSS: dispondo elementos com Flexbox e Grid

Gostaria de entender o motivo pelo qual os ícones não aparem para mim. Obrigado

<!DOCTYPE html>
<html lang="pt-br">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>HZC | Home</title>
    <link rel="preconnect" href="https://fonts.googleapis.com">
    <link rel="preconnect" href="https://fonts.gstatic.com" crossorigin>
    <link rel="stylesheet" href="https://fonts.googleapis.com/css2?family=Open+Sans:wght@400;600;700&display=swap">
    <link rel="stylesheet" href="assets/css/reset.css">
    <link rel="stylesheet" href="assets/css/estilos.css">
</head>
<body>
    <header class="cabecalho">
        <button class="cabecalho__menu" aria-label="Menu"><i></i></button>
        <img src="assets/img/logo.svg" alt="Logotipo da HZC" class="cabecalho__logo">
        <button class="cabecalho__notificacao" aria-label="Notificação"><i></i></button>
    </header>
    <nav class="menu-lateral">
        <img src="assets/img/logo.svg" alt="Logotipo da HZC" class="menu-lateral__logo">
        <a href="#" class="menu-lateral__link menu-lateral__link--inicio menu-lateral__link--ativo">Início</a>
        <a href="#" class="menu-lateral__link menu-lateral__link--videos">Vídeos</a>
        <a href="#" class="menu-lateral__link menu-lateral__link--picos">Picos</a>
        <a href="#" class="menu-lateral__link menu-lateral__link--integrantes">Integrantes</a>
        <a href="#" class="menu-lateral__link menu-lateral__link--camisas">Camisas</a>
        <a href="#" class="menu-lateral__link menu-lateral__link--pinturas">Pinturas</a>
    </nav>
    <script src="index.js"></script>
</body>
</html>

@font-face {
    font-family: 'icones';
    src: url(../font/icones.ttf);
}

body {
    background-color: #1D232A;
    font-family: 'Open Sans', 'icones', sans-serif;
    color: #FFFFFF
}

.cabecalho {
    display: flex;
    justify-content: space-between;
    align-items: center;
    background-color: #15191C;
    padding: 8px 16px; 
    box-shadow: 0px 4px 4px rgba(0, 0, 0, 0.16);
}

.cabecalho__menu i::before {
    content: "\e904";
    font-size: 24px;
}

.cabecalho__notificacao i::before {
    content: "\e906";
    font-size: 24px;
}

.cabecalho__logo {
    width: 40px;
}

.menu-lateral {
    display: flex;
    flex-direction: column;
    background-color: #15191C;
    width: 75vw;
    height: 100vh;
}

.menu-lateral__logo {
    width: 118px;
    align-self: center;
    padding: 16px;
}

.menu-lateral__link {
    height: 64px;
    color: #95999C;
    padding-left: 64px;
    display: flex;
    align-items: center;
}

.menu-lateral__link--ativo {
    color: #FFFFFF;
    padding-left: 56px;
    border-left: 8px solid #FFFFFF;
}

.menu-lateral__::before {
    content: "\e900";
    width: 24px;
    height: 24px;
    font-size: 24px;
    position: absolute;
    left: 24px;
}

.menu-lateral__link--inicio {
    content: "\e902";
}

.menu-lateral__link--videos {
    content: "\e90e";
}

.menu-lateral__link--picos {
    content: "\e909";
}

.menu-lateral__link--integrantes {
    content: "\e903";
}

.menu-lateral__link--camisas {
    content: "\e900";
}

.menu-lateral__link--pinturas {
        content: "\e90a";
}