:root {
  --primary: #007bff;
  --primary-dark: #0474ec;
  --bg: #f4f4f4;
  --surface-bg: #fff;
  --text: #333;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: Arial, sans-serif;
  background-color: var(--bg);
}

.container {
  display: flex;
  justify-content: center;
  align-items: center;
  flex-direction: column;
  gap: 2rem;

  max-width: 900px;
  height: min-content;
  padding: 2rem;
  margin: 10rem auto;

  color: var(--text);
  background-color: var(--surface-bg);
  border-radius: 12px;
  box-shadow: 0 10px 25px  rgba(0, 0, 0, 0.08);
}

.container__title {
    font-size: 2rem;
    line-height: 1.3;
    text-align: center;

    letter-spacing: -0.5px;

    color: var(--text);
    transition: color 0.3s ease, opacity 0.3s ease;
  }

.container__title.active {
  color: var(--primary);
  font-weight: 600;
}

.container__btn-toggle {
  padding: 0.5rem 1rem;
  background-color: var(--primary);
  color: #fff;
  border: none;
  border-radius: 0.25rem;
  cursor: pointer;
  transition: background-color 0.3s ease-out, transform 0.3s ease-out;
}

.container__btn-toggle:hover {
      background-color: var(--primary-dark);
      transform: translateY(-2px);
    }

.container__btn-toggle:active {
  transform: translateY(0) scale(0.96);
}