body {
    font-family: 'GFS Didot', serif;
    background-color: #0f0f0f;
    background-image: 
        linear-gradient(rgba(255, 255, 255, 0.03) 1px, transparent 1px),
        linear-gradient(90deg, rgba(255, 255, 255, 0.03) 1px, transparent 1px);
    background-size: 30px 30px;
    color: #e0e0e0;
    display: flex;
    flex-direction: column; /* ΤΟΥ ΛΕΕΙ ΝΑ ΒΑΖΕΙ ΤΑ ΣΤΟΙΧΕΙΑ ΑΠΟ ΚΑΤΩ */
    align-items: center;    /* ΤΑ ΚΡΑΤΑΕΙ ΣΤΟ ΚΕΝΤΡΟ */
    padding: 20px;
}

.container {
    background-color: #1a1a1a;
    padding: 25px;
    border-radius: 15px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.7);
    max-width: 650px;
    width: 100%;
    text-align: center;
}

.mascot {
    width: 150px;
    height: 150px;
    object-fit: cover;
    border-radius: 50%;
    border: 4px solid #bb86fc;
    margin: 0 auto 15px auto;
    display: block;
    box-shadow: 0 4px 15px rgba(0,0,0,0.5);
}

h1 { color: #ffffff; font-weight: normal; margin-top: 0; }

.grade-selector { margin-bottom: 20px; }

select {
    padding: 8px; background: #2c2c2c; color: white;
    border: 1px solid #444; font-family: 'GFS Didot';
    border-radius: 5px; max-width: 100%;
}

.highlight-text { font-weight: bold; color: #ff9800; }

.equation-text { font-size: 28px; color: #bb86fc; margin: 20px 0; }

.input-container input {
    padding: 10px; font-size: 18px; background: #2c2c2c;
    border: 1px solid #444; color: white;
    border-radius: 5px; max-width: 150px;
}

.buttons-group {
    display: flex; gap: 10px; justify-content: center;
    margin-top: 15px; flex-wrap: wrap;
}

/* --- Κουμπιά & Εφέ Λάμψης --- */
button {
    font-family: 'GFS Didot', serif; 
    padding: 10px 15px;
    border: none; 
    border-radius: 5px; 
    cursor: pointer;
    font-weight: bold;
    transition: all 0.3s ease; /* Κάνει την αλλαγή ομαλή */
}

.kbd-toggle { background: #444; color: white; }

.check-btn { background-color: #03dac6; color: black; }
.check-btn:hover { transform: translateY(-2px); box-shadow: 0 5px 15px rgba(3, 218, 198, 0.4); }

.help-btn { background-color: #cf6679; color: black; }
.help-btn:hover { transform: translateY(-2px); box-shadow: 0 5px 15px rgba(207, 102, 121, 0.4); }

.skip-btn { background-color: #555; color: white; }
.skip-btn:hover { transform: translateY(-2px); box-shadow: 0 5px 15px rgba(255, 255, 255, 0.2); }

.reset-btn { background: transparent; color: #cf6679; border: 1px solid #cf6679; margin-top: 20px; }

/* ΝΕΟ ΣΤΥΛ ΠΛΗΚΤΡΟΛΟΓΙΟΥ 5 ΣΤΗΛΩΝ */
.math-keyboard {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 5px;
    margin: 15px 0;
    background: #252525;
    padding: 10px;
    border-radius: 8px;
}

.math-keyboard button { 
    background: #3d3d3d; 
    color: white; 
    font-size: 16px; 
    padding: 8px 5px;
}

.hidden { display: none !important; }

.help-steps {
    text-align: left; background: #252525; padding: 15px;
    border-left: 4px solid #bb86fc; margin-top: 15px;
    font-size: 16px; line-height: 1.6;
}

.graph-box {
    width: 100%; height: 350px; margin-top: 20px;
    border-radius: 8px; border: 1px solid #333;
}

.lessons-section {
    margin-top: 30px; border-top: 1px solid #333;
    padding-top: 15px; text-align: left;
}

.resources-list { list-style: none; padding: 0; }
.resources-list li { margin-bottom: 10px; }
.resources-list a { color: #03dac6; text-decoration: none; font-size: 16px; }
.resources-list a:hover { text-decoration: underline; }

.stats-btn {
    background-color: transparent; color: #bb86fc;
    border: 1px solid #bb86fc; font-size: 14px;
    margin-top: 10px; padding: 5px 15px;
}
.stats-btn:hover { background-color: rgba(187, 134, 252, 0.1); }

/* --- Στατιστικά Modal --- */
.modal {
    position: fixed; top: 0; left: 0; width: 100%; height: 100%;
    background-color: rgba(0,0,0,0.8); display: flex;
    justify-content: center; align-items: center; z-index: 1000;
}

.modal-content {
    background-color: #1a1a1a; padding: 30px; border-radius: 10px;
    border: 2px solid #bb86fc; text-align: center; min-width: 300px;
}

.stat-num { font-size: 24px; color: #03dac6; font-weight: bold; }

/* --- Στυλ για το Πλαίσιο Σημειώσεων --- */
.notes-container { margin-top: 20px; text-align: left; }
.notes-container label { display: block; font-size: 14px; color: #bb86fc; margin-bottom: 5px; }

#user-notes {
    width: 100%; height: 100px; background-color: #2c2c2c;
    color: #ffffff; border: 1px solid #444; border-radius: 8px;
    padding: 10px; font-family: 'GFS Didot', serif; font-size: 16px;
    resize: vertical; box-sizing: border-box;
}

#user-notes:focus { outline: none; border-color: #03dac6; }