:root {
  --background-color: #434f6d;

  --main-padding: 2rem;
  --main-max-width: 470px;

  --section-padding: 2rem;
  --section-box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
  --section-border-radius: 0.5rem;
  --section-background-color: #fff;

  --font-family: Arial, sans-serif;
  --input-padding: 10px;
  --input-border-color: #ccc;
  --input-border-radius: 4px;
  --submit-background-color: #007bff;
  --submit-hover-background-color: #0056b3;
  --submit-color: #fff;
}

* {
  box-sizing: border-box;
}

body {
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
  margin: 0;
  font-family: var(--font-family);
  background-color: var(--background-color);
}

.flex {
  display: flex;
}

.flex-col {
  flex-direction: column;
}

.flex-start {
  justify-content: flex-start;
}

.align-center {
  align-items: center;
}

.align-start {
  align-items: flex-start;
}

main {
  display: flex;
  flex-direction: column;
  min-width: var(--main-max-width);
  padding: var(--main-padding);
}

section {
  background-color: var(--section-background-color);
  padding: var(--section-padding);
  border-radius: var(--section-border-radius);
  box-shadow: var(--section-box-shadow);
  gap: 20px;
}

header h1 {
  margin: 0;
}

form {
  gap: 20px;
}

label {
  display: flex;
}

input[type="text"],
input[type="password"] {
  padding: var(--input-padding);
  border: 1px solid var(--input-border-color);
  border-radius: var(--input-border-radius);
  width: 100%;
}

input[type="submit"] {
  padding: var(--input-padding);
  border: none;
  border-radius: var(--input-border-radius);
  background-color: var(--submit-background-color);
  color: var(--submit-color);
  cursor: pointer;
}

input[type="submit"]:hover {
  background-color: var(--submit-hover-background-color);
}

.error-message {
  color: red;
}

.hidden {
  display: none;
}

a {
  color: black;
  text-decoration: none;
}

.active {
  font-weight: bold;
}