* {
    box-sizing: border-box;
    font-family: 'Segoe UI', Tahoma, sans-serif;
}

body {
    margin: 0;
    height: 100vh;
    background: #0d47a1;
    display: flex;
    justify-content: center;
    align-items: center;
}

/* FONDO CON MARCA DE AGUA */
.background {
    position: fixed;
    inset: 0;
    background: 
        linear-gradient(120deg, rgba(13,71,161,.15), rgba(255,255,255,.35)),
        url('../img/fondo_isalud.png') center / cover no-repeat;
    z-index: -1;
}

/* CAJA LOGIN */
.login-box {
    width: 380px;
    background: white;
    border-radius: 16px;
    padding: 35px;
    box-shadow: 0 15px 40px rgba(0,0,0,.35);
    text-align: center;
    animation: fadeIn .8s ease;
}

@keyframes fadeIn {
    from { opacity:0; transform: translateY(15px); }
    to { opacity:1; transform: translateY(0); }
}

/* LOGO */
.logo i {
    font-size: 48px;
    color: #1976d2;
}

.logo h1 {
    margin: 10px 0 0;
    color: #1976d2;
}

.logo p {
    margin: 4px 0 20px;
    color: #777;
}

/* INPUTS */
.input-group {
    position: relative;
    margin-bottom: 18px;
}

.input-group i {
    position: absolute;
    left: 12px;
    top: 50%;
    transform: translateY(-50%);
    color: #999;
}

.input-group input {
    width: 100%;
    padding: 12px 12px 12px 38px;
    border-radius: 8px;
    border: 1px solid #ccc;
    font-size: 15px;
}

.input-group input:focus {
    border-color: #1976d2;
    outline: none;
}

/* BOTÓN */
button {
    width: 100%;
    padding: 12px;
    border: none;
    border-radius: 8px;
    background: linear-gradient(90deg, #1976d2, #2196f3);
    color: white;
    font-size: 16px;
    cursor: pointer;
}

button:hover {
    opacity: .9;
}

/* ERROR */
.error {
    background: #fdecea;
    color: #c62828;
    padding: 10px;
    border-radius: 8px;
    margin-bottom: 15px;
    font-size: 14px;
}

/* FOOTER */
.footer {
    margin-top: 18px;
    font-size: 12px;
    color: #999;
}