:root {
  --green: #03cf5d;
  --focus: #24388d;
  --border-gray: #dadada;
  --error-bg: #e9f0fd;
  --error-text: #ff0000;
  --black: #121212;
  --text-gray: #999999;

  --side-gap: 1.25rem;
  --max-width: 31.25rem; /* -> 500px */
}

/* Reset & Base */
* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  padding: 0;
  inline-size: 100%;
  block-size: 100%;
}

body {
  font-size: 1rem;
  color: var(--black);
}

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

button {
  border: none;
  background: none;
}

/* Top Bar */
.top-bar {
  position: fixed;
  inset-block-start: 0;
  inset-inline-start: 0;
  inline-size: 100%;
  block-size: 3rem;

  display: flex;
  align-items: center;
  padding-inline: var(--side-gap);

  background-color: #fff;
  z-index: 10;
}

/* Logo */
.login-container {
  margin-block-start: 5rem;
  margin-block-end: 2.5rem;
}

.logo {
  inline-size: 230px;
  margin-inline: auto;

  svg {
    display: block;
    inline-size: 100%;
    block-size: auto;
  }

  a:focus-visible {
    outline: 2px solid var(--focus);
    outline-offset: 4px;
  }
}

/* Main */
.main {
  padding-inline: var(--side-gap);

  @media (min-width: 48rem) {
    display: flex;
    justify-content: center;
  }
}

/* Form */
.mainform {
  display: flex;
  flex-direction: column;

  @media (min-width: 48rem) {
    inline-size: 100%;
    max-inline-size: var(--max-width);
  }

  /* ---------- 입력 그룹 ---------- */
  .form-group {
    display: flex;
    flex-direction: column;
    margin-block-end: 0.625rem;

    input {
      inline-size: 100%;
      block-size: 2.8125rem;
      padding-inline: 0.875rem;

      font-size: 0.875rem;
      border: 1px solid var(--border-gray);
      background-color: #fff;
      outline: none;

      &:hover {
        background-color: var(--error-bg);
      }

      &:focus {
        border-color: var(--green);
        background-color: var(--error-bg);
      }

      &:not(:placeholder-shown):invalid {
        border-color: var(--error-text);

        + .err {
          display: block;
        }
      }
    }

    .err {
      display: none;
      font-size: 0.75rem;
      color: var(--error-text);
      margin-block-start: 0.25rem;
    }
  }

  /* ---------- 로그인 버튼 ---------- */
  button {
    margin-block-start: 1.25rem;
    block-size: 2.8125rem;

    font-size: 1rem;
    font-weight: 700;

    background-color: var(--green);
    color: #fff;
    cursor: pointer;
  }

  /* 로그인 클릭 (아무 것도 입력 안 했을 때) */
  &:has(:user-invalid) {
    .err {
      display: block;
    }

    input:invalid {
      border-color: var(--green);
    }
  }
}

/* Options */
.options {
  display: flex;
  align-items: center;
  margin-block-start: 0.625rem;

  /* 로그인 상태 유지 */
  .loginState {
    display: inline-flex;
    align-items: center;
    cursor: pointer;

    input {
      appearance: none;
      inline-size: 1.5rem; /* 24px */
      block-size: 1.5rem;
      margin-inline-end: 0.3125rem; /* 5px */
      background: url('../img/unchecked.svg') no-repeat center;
    }

    input:checked {
      background-image: url('../img/checked.svg');
    }
  }

  /* IP 보안 */
  .ipSecurity {
    display: none;
    margin-inline-start: auto;
    align-items: center;

    @media (min-width: 48rem) {
      display: flex;
    }

    .ipToggle {
      display: inline-flex;
      align-items: center;
      margin-inline-start: 0.3125rem;
      cursor: pointer;
      font-size: 1rem;
      color: var(--black);

      input {
        appearance: none;
      }

      .off {
        color: var(--text-gray);
      }

      .on {
        display: none;
        color: var(--green);
      }

      input:checked ~ .off {
        display: none;
      }

      input:checked ~ .on {
        display: inline;
      }

      &:focus-within {
        outline: 2px solid var(--focus);
        outline-offset: 4px;
      }
    }
  }
}