@import url('https://fonts.googleapis.com/css2?family=Roboto:ital,wght@0,100;0,300;0,400;0,500;0,700;0,900;1,100;1,300;1,400;1,500;1,700;1,900&display=swap');

:root{
  --ink:#111;         /* negro principal */
  --ink-2:#555;       /* gris texto secundario */
  --paper:#fff;       /* blanco tarjeta */
}

/* Reset básico */
*{ box-sizing:border-box; }
html, body{
  height:100%;
  margin:0;
  font-family:"Roboto", system-ui, -apple-system, Segoe UI, Helvetica, Arial, sans-serif;
  font-weight:300;
}

/* Fondo (tu gradiente) */
body{
  min-height:100vh;
  display:flex;
  align-items:center;
  justify-content:center;
  background: #b0b0b0;
  background: linear-gradient(90deg, rgba(176,176,176,1) 0%, rgba(71,71,71,1) 100%);
}

/* Header (logo) */
.main-header {
  padding: 15px 40px;
  display: flex-start;
  align-items: left;
  position: absolute;
  top: 0;
  left: 0;
}

.main-header .logo {
  display: flex;
  align-items: left;
}

.main-header .logo img {
  max-height: 60px;
}

/* Tarjeta de login */
.signin{
  width:min(100%, 380px);
  background:var(--paper);
  border-radius:16px;
  padding:15px;
  border:1px solid rgba(0,0,0,.08);
  /* Sombra negra agradable sobre gris */
  box-shadow:
    0 24px 44px -20px rgba(0,0,0,.45),
    0 12px 24px -12px rgba(0,0,0,.28),
    0 0 0 1px rgba(0,0,0,.04);
  transition: box-shadow .25s ease, transform .25s ease;
}
.signin:hover{
  transform:translateY(-1px);
  box-shadow:
    0 30px 60px -24px rgba(0,0,0,.55),
    0 16px 30px -14px rgba(0,0,0,.34),
    0 0 0 1px rgba(0,0,0,.05);
}

.signin .group{ margin-bottom:16px; }

/* Título */
.signin .group.head h2{
  margin:0 0 6px;
  text-align:center;
  color:var(--ink);
  font-weight:900;
  letter-spacing:.2px;
}

/* Etiquetas */
.signin .group label{
  display:block;
  margin-bottom:6px;
  font-size:1.1rem;
  font-weight:600;
  color:var(--ink);
}

/* Inputs */
.signin .group input{
  width:100%;
  padding:.7rem .9rem;
  border:1.6px solid var(--ink);
  border-radius:8px;
  font-size:16px;
  color:var(--ink);
  background:var(--paper);
  transition: background .2s, color .2s, border-color .2s, box-shadow .2s;
}
.signin .group input::placeholder{ color:#7a7a7a; }
.signin .group input:hover{ border-color:#000; }
.signin .group input:focus{
  outline:none;
  box-shadow:0 0 0 3px rgba(0,0,0,.12) inset;
}

/* Botón (negro → blanco al hover, como pediste) */
.signin .group button{
  width:100%;
  padding:.7rem 1rem;
  font-size:1.05rem;
  font-weight:700;
  border-radius:8px;
  border:2px solid #000;
  background:#000;
  color:#fff;
  cursor:pointer;
  transition: background .2s, color .2s, border-color .2s, transform .05s;
}
.signin .group button:hover{
  background:#fff;
  color:#000;
  border-color:#000;
}
.signin .group button:active{ transform:translateY(1px); }

/* Link “¿Olvidaste tu contraseña?” */
.forgot-pass-link{ text-align:center; margin-top:.75rem; }
.signin .group .forgot-pass-link a{
  color:var(--ink-2);
  text-decoration:none;
  text-underline-offset:3px;
  text-decoration-thickness:1px;
}
.signin .group .forgot-pass-link a:hover{
  color:#000;
  text-decoration:underline;
}

/* Icono de mostrar/ocultar password si lo usas */
.signin form{ position:relative; }
.field-icon{
  position:absolute;
  right:12px;
  top:50%;
  transform:translateY(-50%);
  cursor:pointer;
  color:#777;
}

/* ====== MÓVIL ====== */
@media screen and (max-width: 768px) {
  body {
    align-items: center;
    justify-content: center;
    min-height: 100vh;
    box-sizing: border-box;
  }

  .main-header {
    padding: 10px 16px;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    width: 100%;
    background: transparent;
    z-index: 1000;
  }

  .main-header .logo img {
    max-height: 60px;
  }

  .signin {
    width: 90%;
    padding: 20px 16px;
    margin: -30px auto 0;
  }

  .signin .group label {
    font-size: 1rem;
  }

  .signin .group input {
    font-size: 16px;
    padding: .8rem 1rem;
  }

  .signin .group button {
    padding: .8rem 1rem;
    font-size: 1rem;
  }
}