:root {
    --primary: #2563eb; /* Azul más serio */
    --bg-dark: #1e293b;
    --text-light: #f8fafc;
}

body {
    margin: 0;
    height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: var(--bg-dark); /* Fondo oscuro */
    font-family: 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
}

.login-container {
    background: #ffffff;
    padding: 3rem;
    width: 100%;
    max-width: 450px;
    /* Sombra dura para efecto "bloque" */
    box-shadow: 8px 8px 0px rgba(0,0,0,0.2); 
    border: 2px solid #000;
}

h1 {
    text-align: left;
    color: #000;
    font-weight: 800;
    text-transform: uppercase;
    letter-spacing: -1px;
    margin-top: 0;
}

.form-group {
    margin-bottom: 1.5rem;
}

label {
    display: block;
    font-weight: 700;
    margin-bottom: 0.5rem;
    color: #334155;
    text-transform: uppercase;
    font-size: 0.8rem;
}

input {
    width: 100%;
    padding: 1rem;
    box-sizing: border-box;
    border: 2px solid #cbd5e1;
    background: #f1f5f9;
    font-size: 1rem;
    transition: all 0.3s ease;
}

input:focus {
    outline: none;
    border-color: var(--primary);
    background: #fff;
}

.btn-submit {
    width: 100%;
    padding: 1rem;
    background: #000;
    color: #fff;
    border: none;
    font-weight: 800;
    text-transform: uppercase;
    cursor: pointer;
    transition: transform 0.2s ease, background 0.2s ease;
}

.btn-submit:hover {
    transform: translateY(-2px);
    background: var(--primary);
    box-shadow: 4px 4px 0 rgba(0,0,0,0.1);
}

.link-register {
    display: block;
    text-align: center;
    margin-top: 1.5rem;
    color: #64748b;
    text-decoration: none;
    font-weight: 600;
}
.link-register:hover { text-decoration: underline; color: var(--primary); }