:root {
  --primario: #1f3864;
  --secundario: #2e75b6;
  --bg: #f5f7fb;
  --gris: #e5e7eb;
  --error: #c00000;
  --info: #1e6091;
}
* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: -apple-system, "Segoe UI", Roboto, Arial, sans-serif;
  background: var(--bg);
  color: #1a1a1a;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
}
.card {
  background: #fff;
  width: 100%;
  max-width: 420px;
  border-radius: 12px;
  box-shadow: 0 10px 40px rgba(0,0,0,.08);
  overflow: hidden;
}
.header {
  background: linear-gradient(135deg, var(--primario), var(--secundario));
  color: #fff;
  padding: 28px 32px;
  text-align: center;
}
.header .icono {
  width: 48px; height: 48px; margin: 0 auto 12px;
  background: rgba(255,255,255,.15);
  border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  font-size: 22px;
}
.header h1 { margin: 0; font-size: 20px; font-weight: 600; }
.header p { margin: 6px 0 0; opacity: .85; font-size: 13px; }
form { padding: 28px 32px 32px; }
label {
  display: block; font-size: 12px; font-weight: 600; color: #555;
  margin-bottom: 6px; text-transform: uppercase; letter-spacing: .5px;
}
input[type=text], input[type=email], input[type=password] {
  width: 100%; padding: 10px 12px; border: 1px solid var(--gris);
  border-radius: 8px; font-size: 14px; background: #fff;
  transition: border .15s;
}
input:focus { outline: none; border-color: var(--secundario); box-shadow: 0 0 0 3px rgba(46,117,182,.15); }
.grupo { margin-bottom: 16px; }
button {
  width: 100%; margin-top: 8px; padding: 12px;
  background: var(--primario); color: #fff; border: none;
  border-radius: 8px; font-size: 15px; font-weight: 600;
  cursor: pointer; transition: background .15s;
}
button:hover { background: var(--secundario); }
.flash { margin: 0 0 16px; padding: 10px 14px; border-radius: 8px; font-size: 13px; }
.flash.error { background: #fde8e8; color: var(--error); border: 1px solid #f5c2c2; }
.flash.info  { background: #e3f0fa; color: var(--info);  border: 1px solid #b6d7ee; }