:root {
    --primary: #0072ff;
    --primary-gradient: linear-gradient(135deg, #00C6FF, #0072FF);
    --bg-dark: #0f172a;
    --glass-bg: rgba(30, 41, 59, 0.7);
    --glass-border: rgba(255, 255, 255, 0.1);
    --text-main: #f8fafc;
    --text-muted: #94a3b8;
    --error: #ef4444;
    --warning: #f59e0b;
    --success: #10b981;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Inter', system-ui, sans-serif;
}

body {
    background-color: var(--bg-dark);
    color: var(--text-main);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    overflow-y: auto;
    overflow-x: hidden;
    position: relative;
    padding: 20px;
}

/* Animación de fondo moderna y fluida */
.background-animation {
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle at center, rgba(0, 198, 255, 0.12) 0%, transparent 45%),
                radial-gradient(circle at 80% 20%, rgba(0, 114, 255, 0.12) 0%, transparent 35%);
    animation: rotateBg 40s linear infinite;
    z-index: 0;
}

@keyframes rotateBg {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

.login-container {
    position: relative;
    z-index: 1;
    width: 100%;
    max-width: 420px;
}

/* Glassmorphism premium */
.glass-panel {
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: 1px solid var(--glass-border);
    border-radius: 24px;
    padding: 40px 30px;
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
    animation: slideUp 0.6s cubic-bezier(0.16, 1, 0.3, 1);
}

@keyframes slideUp {
    from { opacity: 0; transform: translateY(30px); }
    to { opacity: 1; transform: translateY(0); }
}

.logo {
    display: flex;
    flex-direction: column;
    align-items: center;
    margin-bottom: 10px;
}

.logo-icon {
    width: 64px;
    height: 64px;
    background: var(--primary-gradient);
    border-radius: 18px;
    margin-bottom: 15px;
    box-shadow: 0 10px 25px rgba(0, 114, 255, 0.4);
    position: relative;
}

.logo-icon::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 32px;
    height: 32px;
    background: url('data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" fill="none" viewBox="0 0 24 24" stroke="white"><path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M17.657 16.657L13.414 20.9a1.998 1.998 0 01-2.827 0l-4.243-4.243a8 8 0 1111.314 0z"/><path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M15 11a3 3 0 11-6 0 3 3 0 016 0z"/></svg>') no-repeat center;
}

h1 {
    font-size: 1.7rem;
    font-weight: 800;
    text-align: center;
    letter-spacing: -0.03em;
}

.subtitle {
    text-align: center;
    color: var(--text-muted);
    font-size: 0.95rem;
    margin-bottom: 30px;
}

.input-group {
    margin-bottom: 22px;
}

.input-group label {
    display: block;
    font-size: 0.85rem;
    font-weight: 600;
    margin-bottom: 8px;
    color: var(--text-muted);
}

.input-group input {
    width: 100%;
    padding: 15px 18px;
    background: rgba(15, 23, 42, 0.6);
    border: 1px solid var(--glass-border);
    border-radius: 14px;
    color: white;
    font-size: 1rem;
    transition: all 0.3s ease;
}

.input-group input:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 4px rgba(0, 114, 255, 0.15);
    background: rgba(15, 23, 42, 0.8);
}

.input-group input:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.btn-primary {
    width: 100%;
    padding: 16px;
    background: var(--primary-gradient);
    border: none;
    border-radius: 14px;
    color: white;
    font-size: 1.05rem;
    font-weight: 700;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    display: flex;
    justify-content: center;
    align-items: center;
    box-shadow: 0 4px 15px rgba(0, 114, 255, 0.3);
}

.btn-primary:hover:not(:disabled) {
    transform: translateY(-3px);
    box-shadow: 0 10px 25px rgba(0, 114, 255, 0.5);
}

.btn-primary:active:not(:disabled) {
    transform: translateY(0);
}

.btn-primary:disabled {
    background: #334155;
    box-shadow: none;
    cursor: not-allowed;
    opacity: 0.6;
}

.btn-small {
    padding: 8px 16px;
    background: rgba(255, 255, 255, 0.1);
    border: 1px solid rgba(255, 255, 255, 0.2);
    color: white;
    border-radius: 8px;
    font-size: 0.85rem;
    font-weight: 600;
    cursor: pointer;
    margin-top: 12px;
    display: inline-block;
    transition: background 0.3s;
}

.btn-small:hover {
    background: rgba(255, 255, 255, 0.25);
}

.alert {
    padding: 16px;
    border-radius: 14px;
    font-size: 0.9rem;
    margin-bottom: 24px;
    line-height: 1.5;
    text-align: center;
    animation: fadeIn 0.4s ease;
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

.alert.warning {
    background: rgba(245, 158, 11, 0.1);
    border: 1px solid rgba(245, 158, 11, 0.3);
    color: #fbbf24;
}

.alert.success {
    background: rgba(16, 185, 129, 0.1);
    border: 1px solid rgba(16, 185, 129, 0.3);
    color: #34d399;
}

.alert.error {
    background: rgba(239, 68, 68, 0.1);
    border: 1px solid rgba(239, 68, 68, 0.3);
    color: #f87171;
}

.message {
    margin-top: 18px;
    text-align: center;
    font-size: 0.9rem;
    font-weight: 500;
}

.message.error { color: var(--error); }
.message.success { color: var(--success); }

.loader {
    border: 3px solid rgba(255,255,255,0.2);
    border-radius: 50%;
    border-top: 3px solid white;
    width: 22px;
    height: 22px;
    animation: spin 0.8s linear infinite;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* Diseño Responsive: 100% adaptado a móviles */
@media (max-width: 480px) {
    .glass-panel {
        padding: 30px 20px;
        border-radius: 20px;
    }
    
    h1 {
        font-size: 1.5rem;
    }
    
    .input-group input {
        padding: 14px;
    }
    
    .btn-primary {
        padding: 15px;
    }
}