/* estilos.css */
:root {
    --primario: #6366f1; /* Indigo */
    --suave: #f5f3ff;    /* Lavanda claro */
    --acento: #8b5cf6;   /* Violeta vibrante */
    --fondo-gradiente: linear-gradient(135deg, #f5f3ff 0%, #ede9fe 100%);
    --boton-gradiente: linear-gradient(to right, #ffffff 0%, #f9f8ff 100%);
    --texto: #1e1b4b;
    --blanco: #ffffff;
}

body {
    font-family: 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
    background: var(--fondo-gradiente);
    background-attachment: fixed;
    color: var(--texto);
    margin: 0;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

header {
    background-color: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(10px);
    padding: 20px;
    text-align: center;
    box-shadow: 0 4px 15px rgba(99, 102, 241, 0.1);
    border-bottom: 3px solid var(--acento);
    position: sticky;
    top: 0;
    z-index: 100;
}

header h1 {
    margin: 0;
    font-size: 1.2rem;
    color: var(--acento);
    text-transform: uppercase;
    letter-spacing: 1px;
}

header p {
    margin: 5px 0 0;
    font-size: 0.9rem;
    color: #6b7280;
}

.contenedor-principal {
    flex: 1;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 20px;
}

.tarjeta {
    background: var(--blanco);
    padding: 35px;
    border-radius: 24px;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.05);
    max-width: 650px;
    width: 100%;
    border: 1px solid rgba(255, 255, 255, 0.6);
}

h2 { 
    color: var(--primario); 
    font-size: 1.4rem; 
    margin-bottom: 25px;
    text-align: center;
}

.lista-botones { display: flex; flex-direction: column; gap: 12px; }

button {
    padding: 18px 24px;
    font-size: 1.05rem;
    text-align: left;
    background: var(--boton-gradiente);
    border: 1px solid #e2e8f0;
    border-radius: 16px;
    cursor: pointer;
    transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    color: var(--texto);
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: 0 2px 5px rgba(0,0,0,0.02);
}

button:hover:not(:disabled) {
    background: linear-gradient(to right, #f5f3ff 0%, #ede9fe 100%);
    border-color: var(--acento);
    transform: scale(1.02);
    box-shadow: 0 8px 20px rgba(139, 92, 246, 0.15);
    color: var(--acento);
}

.btn-volver {
    background: none;
    border: none;
    color: var(--acento);
    font-weight: bold;
    font-size: 0.9rem;
    margin-bottom: 15px;
    padding: 5px;
    text-decoration: underline;
    cursor: pointer;
    display: inline-block;
}

.enunciado { 
    font-size: 1.3rem; 
    line-height: 1.6;
    background: linear-gradient(to right, var(--texto), var(--primario));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 35px;
    font-weight: 600;
}

.correcta { background-color: #dcfce7 !important; border-color: #22c55e !important; color: #166534; }
.incorrecta { background-color: #fee2e2 !important; border-color: #ef4444 !important; color: #991b1b; }

.progress-bar {
    height: 6px;
    background: #e5e7eb;
    border-radius: 10px;
    margin-bottom: 20px;
    overflow: hidden;
}
.progress-fill {
    height: 100%;
    background: var(--acento);
    width: 0%;
    transition: width 0.4s ease;
}

.mensaje-info { text-align: center; color: #888; }