style.css

@import url("https://fonts.googleapis.com/css2?family=Poppins:wght@400;500;600&display=swap");

:root {
  --body-bg: #262a2f;
  --gray: #d1d1d1;
  --white: #fff;
  --blue: #494eea;
}

* {
  margin: 0;
  padding: 0;
  font-family: "Poppins", sans-serif;
  box-sizing: border-box;
}

body {
  background: var(--body-bg);
  padding: 1rem;
  width: 100%;
  min-height: 100dvh;
  display: flex;
  justify-content: center;
  align-items: center;
  flex-direction: column;
}

.container {
  width: 24rem;
  padding: 1.5rem 2rem;
  background: var(--white);
  border-radius: 10px;
  @media (max-width: 768px) {
    width: 80%;
  }
  & > p {
    font-weight: 600;
    font-size: 1rem;
    margin-bottom: 0.5rem;
    text-align: center;
    color: var(--blue);
  }
  & > input {
    width: 100%;
    height: 3rem;
    border: 1px solid var(--blue);
    padding: 1rem;
    margin: 0.625rem 0 1.25rem;
    border-radius: 0.25rem;
  }
  & > button {
    width: 100%;
    height: 3rem;
    background: var(--blue);
    color: var(--white);
    border: 0;
    outline: 0;
    border-radius: 0.25rem;
    box-shadow: 0 0.625rem 0.625rem rgba(0, 0, 0, 0.1);
    margin: 1.25rem 0;
    font-weight: 500;
    cursor: pointer;
  }
}

#imgBox {
  width: 12.5rem;
  aspect-ratio: 1/1;
  border-radius: 0.25rem;
  max-height: 0;
  overflow: hidden;
  transition: max-height 1s ease-in-out;
  & > img {
    width: 100%;
    padding: 0.5rem;
  }
  &.show-img {
    max-height: 18.75rem;
    margin: 0.625rem auto;
    border: 1px solid var(--gray);
  }
}

.error {
  animation: shake 0.1s linear 10;
}

@keyframes shake {
  0% {
    transform: translateX(0);
  }
  25% {
    transform: translateX(-2px);
  }
  50% {
    transform: translateX(0);
  }
  75% {
    transform: translateX(2px);
  }
  100% {
    transform: translateX(0);
  }
}