:root {
  --brand: #002b5c;
  --brand-hover: #003f85;
  --brand-active: #001f42;
  --text-strong: #1f2937;
  --text: #374151;
  --text-muted: #6b7280;
  --text-faint: #9ca3af;
  --border: #e5e7eb;
  --surface: #ffffff;
  --surface-muted: #f9fafb;
  --danger: #dc2626;
  --danger-soft: #f87171;
  --danger-bg: #fef2f2;
  --danger-border: #fecaca;
  --warning: #d97706;
  --warning-bg: #fffbeb;
  --warning-border: #fde68a;
}

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

html {
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue",
    Arial, sans-serif;
  line-height: 1.5;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 2.5rem 1rem;
  background-image: linear-gradient(
      135deg,
      rgba(0, 0, 0, 0.82) 0%,
      rgba(0, 43, 92, 0.75) 100%
    ),
    url("https://fcen.unal.edu.co/fileadmin/imagenes/fotos_paginas_programas/wpatio.jpg");
  background-size: cover;
  background-position: center;
}

.card {
  width: 100%;
  max-width: 28rem;
  /* min-width: auto (por defecto en flex) impide encoger bajo el contenido:
     el logo de 18rem y el correo del pie desbordarian en pantallas < 22rem */
  min-width: 0;
  padding: 2rem;
  background-color: var(--surface);
  border-radius: 1rem;
  border-top: 4px solid var(--brand);
  box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
}

.logo {
  display: flex;
  justify-content: center;
  margin-bottom: 1.75rem;
}

.logo img {
  width: 18rem;
  max-width: 100%;
  height: 4rem;
  object-fit: contain;
}

.title {
  margin: 0 0 0.25rem;
  font-size: 1.25rem;
  line-height: 1.75rem;
  font-weight: 700;
  text-align: center;
  letter-spacing: -0.025em;
  color: var(--text-strong);
}

.field-label {
  display: block;
  margin-bottom: 0.25rem;
  font-size: 0.75rem;
  line-height: 1rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.025em;
  color: var(--text-muted);
}

.field {
  width: 100%;
  padding: 0.625rem 1rem;
  font-family: inherit;
  font-size: 0.875rem;
  line-height: 1.25rem;
  color: var(--text);
  background-color: var(--surface);
  border: 1px solid var(--border);
  border-radius: 0.5rem;
  transition: border-color 0.2s, box-shadow 0.2s;
}

.field:focus {
  border-color: var(--brand);
  box-shadow: 0 0 0 3px rgba(0, 43, 92, 0.15);
  outline: none;
}

.field.is-invalid {
  border-color: var(--danger-soft);
}

select.field {
  margin-bottom: 1rem;
  background-color: var(--surface-muted);
}

select.field:disabled {
  cursor: not-allowed;
}

input.field {
  margin-bottom: 1.25rem;
}

.button {
  width: 100%;
  padding: 0.625rem 1rem;
  font-family: inherit;
  font-size: 0.875rem;
  line-height: 1.25rem;
  font-weight: 600;
  color: #ffffff;
  background-color: var(--brand);
  border: 0;
  border-radius: 0.5rem;
  cursor: pointer;
  transition: background-color 0.2s, opacity 0.2s;
}

.button:hover {
  background-color: var(--brand-hover);
}

.button:active {
  background-color: var(--brand-active);
}

.button:disabled {
  background-color: var(--brand);
  opacity: 0.5;
  cursor: not-allowed;
}

.message {
  margin-top: 1.25rem;
}

.message--loading {
  text-align: center;
  font-size: 0.875rem;
  line-height: 1.25rem;
  font-weight: 500;
  color: var(--brand);
}

.spinner {
  display: inline-block;
  width: 1.1rem;
  height: 1.1rem;
  margin-right: 0.4rem;
  vertical-align: middle;
  border: 2px solid rgba(0, 43, 92, 0.25);
  border-top-color: var(--brand);
  border-radius: 50%;
  animation: spin 0.7s linear infinite;
}

@keyframes spin {
  to {
    transform: rotate(360deg);
  }
}

.alert {
  margin: 0;
  padding: 0.75rem;
  text-align: center;
  font-size: 0.875rem;
  line-height: 1.25rem;
  font-weight: 500;
  border: 1px solid;
  border-radius: 0.5rem;
}

.alert--error {
  color: var(--danger);
  background-color: var(--danger-bg);
  border-color: var(--danger-border);
}

.alert--warning {
  color: var(--warning);
  background-color: var(--warning-bg);
  border-color: var(--warning-border);
}

.footer {
  margin-top: 1.75rem;
  text-align: center;
  overflow-wrap: anywhere;
}

.footer small {
  font-size: 0.75rem;
  line-height: 1rem;
  color: var(--text-faint);
}

.footer a {
  font-weight: 500;
  color: var(--text-muted);
  text-decoration: underline;
  transition: color 0.2s;
}

.footer a:hover {
  color: var(--brand);
}

@keyframes shake {
  0%,
  100% {
    transform: translateX(0);
  }
  20%,
  60% {
    transform: translateX(-0.375rem);
  }
  40%,
  80% {
    transform: translateX(0.375rem);
  }
}

.shake {
  animation: shake 0.4s ease;
}

.hidden {
  display: none;
}