:root {
  --ink: #07163d;
  --muted: #63708a;
  --line: #dce5f4;
  --blue: #126bff;
  --cyan: #18c8ff;
  --violet: #7b3dff;
  --navy: #020817;
  --surface: #ffffff;
  --soft: #f3f7ff;
  --shadow: 0 18px 44px rgba(5, 19, 52, 0.12);
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

body {
  min-height: 100vh;
  margin: 0;
  color: var(--ink);
  font-family: "Inter", "Pretendard", "Noto Sans KR", "Segoe UI", Arial, sans-serif;
  background:
    radial-gradient(circle at 78% 12%, rgba(24, 200, 255, 0.18), transparent 32%),
    linear-gradient(180deg, #f4f8ff 0%, #ffffff 52%, #edf5ff 100%);
}

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

button,
input {
  font: inherit;
}

.auth-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  min-height: 72px;
  padding: 14px clamp(18px, 4vw, 56px);
  color: #fff;
  background: rgba(2, 8, 23, 0.94);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
}

.brand-mark {
  display: grid;
  grid-template-columns: repeat(5, 5px);
  align-items: end;
  gap: 5px;
  width: 40px;
  height: 40px;
}

.brand-mark span {
  display: block;
  border-radius: 6px;
  background: linear-gradient(180deg, var(--cyan), var(--blue));
}

.brand-mark span:nth-child(1) { height: 16px; }
.brand-mark span:nth-child(2) { height: 26px; }
.brand-mark span:nth-child(3) { height: 34px; }
.brand-mark span:nth-child(4) { height: 23px; }
.brand-mark span:nth-child(5) { height: 18px; }

.brand strong {
  display: block;
  font-size: 24px;
  line-height: 1;
  white-space: nowrap;
}

.brand em {
  display: block;
  margin-top: 4px;
  color: #58c7ff;
  font-size: 10px;
  font-style: normal;
  font-weight: 900;
  letter-spacing: 2.8px;
  white-space: nowrap;
}

.home-link {
  min-height: 42px;
  padding: 0 16px;
  border: 1px solid rgba(195, 211, 255, 0.34);
  border-radius: 12px;
  display: inline-flex;
  align-items: center;
  color: #fff;
  font-weight: 900;
}

.auth-shell {
  display: grid;
  place-items: center;
  min-height: calc(100vh - 72px);
  padding: 40px 18px;
}

.auth-card {
  width: min(100%, 460px);
  padding: 28px;
  border: 1px solid rgba(209, 220, 240, 0.96);
  border-radius: 20px;
  background: rgba(255, 255, 255, 0.96);
  box-shadow: var(--shadow);
}

.eyebrow {
  margin: 0 0 10px;
  color: var(--blue);
  font-size: 12px;
  font-weight: 950;
  letter-spacing: 3px;
  text-transform: uppercase;
}

h1 {
  margin: 0 0 10px;
  font-size: clamp(30px, 8vw, 42px);
  line-height: 1.1;
  letter-spacing: 0;
}

.auth-card > p {
  margin: 0 0 22px;
  color: var(--muted);
  font-weight: 750;
  line-height: 1.65;
  word-break: keep-all;
}

.auth-form {
  display: grid;
  gap: 14px;
}

.auth-form label {
  display: grid;
  gap: 7px;
  color: #26385d;
  font-size: 13px;
  font-weight: 900;
}

.auth-form input {
  width: 100%;
  min-height: 50px;
  padding: 0 14px;
  border: 1px solid var(--line);
  border-radius: 12px;
  color: var(--ink);
  background: #fbfdff;
  font-weight: 800;
}

.auth-form input[type="checkbox"] {
  width: 18px;
  min-height: 18px;
  padding: 0;
}

.check-row {
  grid-template-columns: 20px 1fr;
  align-items: center;
  gap: 10px;
}

.auth-form input:focus {
  outline: 3px solid rgba(18, 107, 255, 0.14);
  border-color: var(--blue);
}

.submit-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 52px;
  border: 0;
  border-radius: 13px;
  color: #fff;
  background: linear-gradient(135deg, #149aff 0%, #126bff 52%, #743cff 100%);
  box-shadow: 0 14px 34px rgba(18, 107, 255, 0.3);
  font-weight: 950;
  cursor: pointer;
}

.auth-message {
  min-height: 24px;
  margin: 2px 0 0;
  color: var(--muted);
  font-size: 13px;
  font-weight: 800;
  line-height: 1.5;
}

.auth-links {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 10px;
  margin-top: 18px;
  color: var(--blue);
  font-size: 14px;
  font-weight: 900;
}

@media (max-width: 520px) {
  .auth-header {
    padding: 12px 16px;
  }

  .brand strong {
    font-size: 21px;
  }

  .brand em {
    font-size: 9px;
    letter-spacing: 2px;
  }

  .home-link {
    display: none;
  }

  .auth-card {
    padding: 22px;
  }
}