:root {
    --primary: #2C3E50;      /* Azul oscuro profesional */
    --primary-light: #3498DB; /* Azul claro para acentos */
    --secondary: #7F8C8D;     /* Gris equilibrado */
    --success: #27AE60;       /* Verde sanación */
    --light-bg: #ECF0F1;      /* Gris muy claro para fondos */
    --white: #FFFFFF;
    --text-dark: #2C3E50;
    --text-light: #7F8C8D;
}

body {
    background: linear-gradient(135deg, #3498DB 0%, #2C3E50 100%);
    font-family: 'Nunito', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    min-height: 100vh;
    margin: 0;
    display: flex;
    align-items: center;
}

.container {
    max-width: 420px;
    padding: 20px;
}

.card {
    border: none;
    border-radius: 20px;
    box-shadow: 0 20px 40px rgba(0,0,0,0.1);
    overflow: hidden;
    background: var(--white);
}

.card-header {
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-light) 100%);
    color: white;
    text-align: center;
    padding: 2.5rem 1.5rem;
    border-bottom: none;
}

.card-header h4 {
    margin: 1rem 0 0;
    font-weight: 400;
    font-size: 1.6rem;
    letter-spacing: 0.5px;
    color: white;
}

.card-header p {
    color: rgba(255,255,255,0.9);
    font-size: 0.9rem;
}

.logo-circle {
    width: 90px;
    height: 90px;
    background: rgba(255,255,255,0.15);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto;
    backdrop-filter: blur(5px);
    border: 2px solid rgba(255,255,255,0.3);
}

.logo-circle i {
    font-size: 3rem;
    color: white;
}

.card-body {
    padding: 2.5rem 2rem;
    background: white;
}

.form-label {
    font-weight: 500;
    color: var(--text-dark);
    font-size: 0.85rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-bottom: 0.5rem;
}

.form-control {
    border-radius: 12px;
    padding: 0.8rem 1rem;
    border: 1.5px solid #E5E9F0;
    font-size: 0.95rem;
    transition: all 0.3s;
    background: #F8FAFD;
}

.form-control:focus {
    border-color: var(--primary-light);
    box-shadow: 0 0 0 4px rgba(52, 152, 219, 0.1);
    background: white;
    outline: none;
}

.form-control::placeholder {
    color: #A0AEC0;
    font-size: 0.9rem;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-light) 100%);
    border: none;
    border-radius: 12px;
    padding: 0.9rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    font-size: 0.9rem;
    transition: all 0.3s;
    color: white;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 20px rgba(52, 152, 219, 0.3);
    background: linear-gradient(135deg, var(--primary-light) 0%, var(--primary) 100%);
}

.btn-primary i {
    font-size: 1rem;
}

.alert {
    border-radius: 12px;
    border: none;
    padding: 1rem 1.2rem;
    margin-bottom: 1.5rem;
    font-size: 0.9rem;
    display: flex;
    align-items: center;
}

.alert-success {
    background: linear-gradient(135deg, #27AE60 0%, #229954 100%);
    color: white;
}

.alert-danger {
    background: linear-gradient(135deg, #E74C3C 0%, #C0392B 100%);
    color: white;
}

.alert i {
    font-size: 1.2rem;
    margin-right: 10px;
}

.text-center a {
    color: var(--primary);
    text-decoration: none;
    font-size: 0.9rem;
    transition: all 0.3s;
    display: inline-block;
    padding: 0.5rem 0;
}

.text-center a:hover {
    color: var(--primary-light);
    text-decoration: none;
    transform: translateX(3px);
}

.text-center a i {
    font-size: 0.8rem;
    transition: transform 0.3s;
}

.text-center a:hover i {
    transform: translateX(3px);
}

/* Toque psicológico: líneas sutiles */
.card-header::after {
    content: '';
    display: block;
    width: 50px;
    height: 3px;
    background: rgba(255,255,255,0.3);
    margin: 15px auto 0;
    border-radius: 2px;
}