:root {
    --phes-font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    --phes-bg: #f7faff;
    --phes-primary: #a0c4ff;
    --phes-primary-dark: #6a9eda;
    --phes-text: #333;
    --phes-border: #cde1ff;
    --phes-white: #fff;
    --phes-correct: #b5e48c;
    --phes-incorrect: #ffadad;
    --phes-disabled: #e0e0e0;
}

#phes-app-container {
    font-family: var(--phes-font);
    background-color: var(--phes-white);
    padding: 25px;
    border-radius: 12px;
    border: 1px solid var(--phes-border);
    max-width: 800px;
    margin: 40px auto;
    color: var(--phes-text);
}

.phes-screen { display: none; }
.phes-screen.active { display: block; }

/* --- Pantalla de Entrada --- */
#phes-input-screen h2 { margin-top: 0; }
#phes-user-text {
    width: 100%;
    min-height: 250px;
    border: 1px solid var(--phes-border);
    border-radius: 8px;
    padding: 15px;
    font-size: 16px;
    resize: vertical;
    box-sizing: border-box;
}
#phes-char-counter {
    text-align: right;
    font-size: 12px;
    color: #888;
    margin-top: 5px;
}
.phes-options-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
    margin: 20px 0;
}
.phes-option-group label { display: block; margin-bottom: 8px; font-weight: 500; }
.phes-option-group input[type="number"] {
    width: 100%;
    padding: 10px;
    border: 1px solid var(--phes-border);
    border-radius: 6px;
    box-sizing: border-box;
}
#phes-generate-btn {
    width: 100%;
    padding: 15px;
    font-size: 18px;
    font-weight: bold;
    background-color: var(--phes-primary-dark);
    color: var(--phes-white);
    border: none;
    border-radius: 8px;
    cursor: pointer;
    transition: background-color 0.2s;
}
#phes-generate-btn:hover { background-color: #5b8bc7; }

/* --- Pantalla de Carga --- */
#phes-loading-screen { text-align: center; }
.phes-spinner {
    width: 50px;
    height: 50px;
    border: 5px solid var(--phes-bg);
    border-top-color: var(--phes-primary-dark);
    border-radius: 50%;
    animation: phes-spin 1s linear infinite;
    margin: 20px auto;
}
@keyframes phes-spin { to { transform: rotate(360deg); } }

/* --- Pantalla de Resultados --- */
.phes-tabs { display: flex; border-bottom: 1px solid var(--phes-border); margin-bottom: 20px; }
.phes-tab-btn {
    padding: 10px 20px;
    border: none;
    background: none;
    cursor: pointer;
    font-size: 16px;
    border-bottom: 3px solid transparent;
}
.phes-tab-btn.active { border-bottom-color: var(--phes-primary-dark); font-weight: bold; }
.phes-tab-content { display: none; }
.phes-tab-content.active { display: block; }

/* Estilos del Examen */
#phes-quiz-header { margin-bottom: 20px; }
#phes-progress-text { font-size: 14px; color: #555; }
#phes-progress-bar-container { background-color: var(--phes-border); border-radius: 5px; height: 10px; overflow: hidden; }
#phes-progress-bar { width: 0%; height: 100%; background-color: var(--phes-primary-dark); transition: width 0.3s; }
#phes-question-text { margin-bottom: 20px; }
#phes-options-container { display: grid; gap: 10px; }
.phes-option-btn {
    width: 100%;
    padding: 15px;
    text-align: left;
    background-color: var(--phes-white);
    border: 1px solid var(--phes-border);
    border-radius: 8px;
    cursor: pointer;
    transition: background-color 0.2s;
}
.phes-option-btn:hover { background-color: var(--phes-bg); }
.phes-option-btn.correct { background-color: var(--phes-correct); border-color: #89c361; }
.phes-option-btn.incorrect { background-color: var(--phes-incorrect); border-color: #e08787; }
.phes-option-btn.disabled { cursor: not-allowed; opacity: 0.7; }

#phes-quiz-feedback { margin-top: 20px; padding: 15px; border-radius: 8px; background-color: var(--phes-bg); }
#phes-next-question-btn, #phes-restart-btn {
    display: block;
    margin: 20px auto 0 auto;
    padding: 12px 25px;
    font-size: 16px;
    background-color: var(--phes-primary-dark);
    color: var(--phes-white);
    border: none;
    border-radius: 8px;
    cursor: pointer;
}
#phes-quiz-results { text-align: center; }
#phes-final-score { font-size: 48px; font-weight: bold; color: var(--phes-primary-dark); margin: 10px 0; }

/* Estilos de las Tarjetas */
.phes-instructions { color: #555; text-align: center; margin-bottom: 20px; }
#phes-flashcards-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
    gap: 20px;
    perspective: 1000px;
}
.phes-flashcard {
    background-color: transparent;
    height: 150px;
    cursor: pointer;
    border-radius: 10px;
}
.phes-flashcard-inner {
    position: relative;
    width: 100%;
    height: 100%;
    text-align: center;
    transition: transform 0.6s;
    transform-style: preserve-3d;
    box-shadow: 0 4px 8px rgba(0,0,0,0.1);
    border-radius: 10px;
}
.phes-flashcard.is-flipped .phes-flashcard-inner { transform: rotateY(180deg); }
.phes-flashcard-front, .phes-flashcard-back {
    position: absolute;
    width: 100%;
    height: 100%;
    -webkit-backface-visibility: hidden;
    backface-visibility: hidden;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 15px;
    border-radius: 10px;
    box-sizing: border-box;
}
.phes-flashcard-front { background-color: var(--phes-white); border: 1px solid var(--phes-border); }
.phes-flashcard-back { background-color: var(--phes-bg); border: 1px solid var(--phes-border); transform: rotateY(180deg); }