:root {
  --bg: #f8f9fa;
  --card: #ffffff;
  --ink: #1a1a2e;
  --muted: #6b7280;
  --line: #e5e7eb;
  --accent: #2563eb;
  --accent-hover: #1d4ed8;
  --error: #dc2626;
  --success: #059669;
  --radius: 10px;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: Inter, "Segoe UI", Roboto, system-ui, sans-serif;
  color: var(--ink);
  background: linear-gradient(135deg, #eef2ff 0%, #f8f9fa 40%, #f0fdf4 100%);
  min-height: 100vh;
}

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

.auth-shell {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  padding: 32px 20px;
}

.auth-header {
  text-align: center;
  margin-bottom: 28px;
}

.auth-logo {
  font-size: 28px;
  font-weight: 700;
  color: var(--ink);
  letter-spacing: -0.5px;
}
.auth-logo:hover { text-decoration: none; }

.auth-subtitle {
  margin: 6px 0 0;
  color: var(--muted);
  font-size: 15px;
}

.auth-card {
  background: var(--card);
  border-radius: var(--radius);
  box-shadow: 0 4px 24px rgba(0, 0, 0, 0.06), 0 1px 3px rgba(0, 0, 0, 0.04);
  width: 100%;
  max-width: 420px;
  padding: 32px 28px;
}

.auth-tabs {
  display: flex;
  border-bottom: 2px solid var(--line);
  margin-bottom: 24px;
}

.auth-tab {
  flex: 1;
  padding: 10px 0;
  background: none;
  border: none;
  font-size: 15px;
  font-weight: 500;
  color: var(--muted);
  cursor: pointer;
  border-bottom: 2px solid transparent;
  margin-bottom: -2px;
  transition: color 0.15s;
}
.auth-tab:hover { color: var(--ink); }

.auth-tab-active {
  color: var(--accent);
  border-bottom-color: var(--accent);
}
.auth-tab-active:hover { color: var(--accent); }

.auth-form {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.auth-form-hidden { display: none; }

.field {
  display: flex;
  flex-direction: column;
  gap: 5px;
}

.field span {
  font-size: 13px;
  font-weight: 500;
  color: var(--muted);
  letter-spacing: 0.01em;
}

.field input {
  padding: 10px 12px;
  border: 1.5px solid var(--line);
  border-radius: 6px;
  font-size: 15px;
  color: var(--ink);
  background: var(--bg);
  transition: border-color 0.15s;
}
.field input:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.btn {
  padding: 11px 20px;
  border: none;
  border-radius: 6px;
  font-size: 15px;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.15s, transform 0.1s;
}
.btn:active { transform: scale(0.98); }

.btn-primary {
  background: var(--accent);
  color: #fff;
}
.btn-primary:hover { background: var(--accent-hover); }
.btn-primary:disabled { opacity: 0.6; cursor: not-allowed; }

.auth-feedback {
  margin: 0;
  font-size: 13px;
  min-height: 20px;
  display: none;
}

.auth-feedback.is-visible { display: block; }

.auth-feedback[data-mode="error"] { color: var(--error); }
.auth-feedback[data-mode="success"] { color: var(--success); }
.auth-feedback[data-mode="idle"] { color: var(--muted); }

.auth-footer-text {
  margin: 20px 0 0;
  font-size: 12px;
  color: var(--muted);
  text-align: center;
  line-height: 1.5;
}

@media (max-width: 480px) {
  .auth-card { padding: 24px 18px; }
}