Simulador CSS

/* =======================
   RESET E BASE
======================= */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: Arial, sans-serif;
    background: linear-gradient(135deg, #1e1e2f, #2c5364);
    color: white;
    text-align: center;
    padding: 20px;
}

/* =======================
   TÍTULOS
======================= */
h1 {
    color: #00f2ff;
    font-size: 42px;
    margin-bottom: 10px;
}

h2 {
    color: #ffd700;
    margin-top: 20px;
}

/* =======================
   TEXTO
======================= */
p {
    font-size: 18px;
    margin: 10px 0;
}

/* =======================
   BOTÃO
======================= */
button {
    padding: 10px 20px;
    background: #00f2ff;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    font-weight: bold;
    transition: 0.3s;
}

button:hover {
    background: #00c3cc;
    transform: scale(1.05);
}

/* =======================
   CAIXA
======================= */
.box {
    margin: 20px auto;
    padding: 20px;
    width: 220px;
    background: #ffffff22;
    border-radius: 10px;
    box-shadow: 0 0 10px #00000055;
}

/* =======================
   FLEXBOX
======================= */
.container-flex {
    display: flex;
    justify-content: center;
    gap: 15px;
    margin-top: 20px;
}

.item {
    background: #00f2ff;
    color: #000;
    padding: 15px;
    border-radius: 8px;
    width: 80px;
}

/* =======================
   GRID
======================= */
.grid {
    display: grid;
    grid-template-columns: repeat(3, 80px);
    gap: 10px;
    justify-content: center;
    margin-top: 20px;
}

.grid div {
    background: #ffd700;
    color: #000;
    padding: 10px;
}

/* =======================
   IMAGEM
======================= */
img {
    width: 150px;
    border-radius: 10px;
    margin-top: 15px;
    transition: 0.3s;
}

img:hover {
    transform: scale(1.1);
}

/* =======================
   LINK
======================= */
a {
    color: #00f2ff;
    text-decoration: none;
}

a:hover {
    text-decoration: underline;
}

/* =======================
   ANIMAÇÃO
======================= */
@keyframes piscar {
    0% { opacity: 1; }
    50% { opacity: 0.3; }
    100% { opacity: 1; }
}

.animado {
    animation: piscar 1s infinite;
    margin-top: 20px;
    font-size: 20px;
    color: #ff4081;
}

/* =======================
   TRANSFORMAÇÃO
======================= */
.rotate:hover {
    transform: rotate(10deg);
    transition: 0.3s;
}

Simulador de CSS

Aula Prática: CSS