/* Signature visuelle commune des exercices - Maths Je m'entraîne
   Chaque exercice garde sa propre mécanique de jeu ; ce fichier ne fournit
   que l'habillage commun (couleurs, header, cartes, boutons, progression). */

:root {
    --exo-primary: #667eea;
    --exo-primary-dark: #764ba2;
    --exo-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --exo-success: #4caf50;
    --exo-warning: #ff9800;
    --exo-danger: #f44336;
}

.exo-body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: var(--exo-gradient);
    min-height: 100vh;
    padding: 20px;
}

.exo-container {
    max-width: 1000px;
    margin: 0 auto;
}

/* Bandeau supérieur : titre + retour */
.exo-header {
    background: rgba(255,255,255,0.95);
    padding: 20px 30px;
    border-radius: 15px;
    margin-bottom: 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 15px;
    box-shadow: 0 5px 20px rgba(0,0,0,0.2);
}
.exo-header h1 { color: var(--exo-primary); font-size: 1.5em; margin: 0; }
.exo-header .exo-subtitle { color: #666; }
.exo-back-btn {
    background: var(--exo-primary);
    color: white;
    padding: 10px 20px;
    border-radius: 25px;
    text-decoration: none;
    font-weight: 500;
    display: inline-flex;
    align-items: center;
    gap: 6px;
}
.exo-back-btn:hover { background: var(--exo-primary-dark); }

/* Barre de progression */
.exo-progress-card {
    background: white;
    border-radius: 15px;
    padding: 25px;
    margin-bottom: 20px;
    box-shadow: 0 5px 20px rgba(0,0,0,0.1);
}
.exo-progress-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 15px;
    flex-wrap: wrap;
    gap: 10px;
}
.exo-progress-title { font-size: 1.2em; color: #333; font-weight: bold; }
.exo-progress-text { color: var(--exo-primary); font-weight: bold; }
.exo-progress-bar { background: #e0e0e0; border-radius: 15px; height: 25px; overflow: hidden; margin-bottom: 10px; }
.exo-progress-fill { height: 100%; background: var(--exo-gradient); border-radius: 15px; transition: width 0.5s ease; }

/* Cartes de contenu (problème, question, résultat...) */
.exo-card {
    background: white;
    border-radius: 15px;
    padding: 25px;
    margin-bottom: 20px;
    box-shadow: 0 5px 20px rgba(0,0,0,0.1);
}
.exo-card-title {
    background: var(--exo-gradient);
    color: white;
    padding: 15px 20px;
    margin: -25px -25px 20px -25px;
    border-radius: 15px 15px 0 0;
    font-size: 1.2em;
    font-weight: bold;
}

/* Champs de saisie */
.exo-input-group { display: flex; flex-direction: column; }
.exo-input-group label { font-size: 0.85em; color: #666; margin-bottom: 5px; }
.exo-input-group input, .exo-input-group select {
    padding: 12px;
    border: 2px solid #ddd;
    border-radius: 8px;
    font-size: 1.1em;
}
.exo-input-group input:focus, .exo-input-group select:focus { outline: none; border-color: var(--exo-primary); }

/* Boutons */
.exo-submit-btn {
    background: var(--exo-gradient);
    color: white;
    border: none;
    padding: 15px 50px;
    border-radius: 30px;
    font-size: 1.2em;
    cursor: pointer;
    display: block;
    margin: 30px auto;
    font-weight: bold;
}
.exo-submit-btn:hover { transform: translateY(-3px); box-shadow: 0 5px 20px rgba(102, 126, 234, 0.4); }

.exo-nav-bar { display: flex; justify-content: center; gap: 15px; margin-top: 20px; flex-wrap: wrap; }
.exo-nav-btn {
    background: white;
    color: var(--exo-primary);
    padding: 12px 30px;
    border-radius: 25px;
    text-decoration: none;
    font-weight: bold;
    box-shadow: 0 3px 10px rgba(0,0,0,0.1);
    border: none;
    cursor: pointer;
}
.exo-nav-btn:hover { transform: translateY(-2px); box-shadow: 0 5px 15px rgba(0,0,0,0.2); }
.exo-nav-btn.exo-nav-primary { background: var(--exo-gradient); color: white; }

/* Messages */
.exo-success {
    background: var(--exo-success);
    color: white;
    padding: 20px;
    border-radius: 15px;
    text-align: center;
    margin-bottom: 20px;
    font-size: 1.2em;
}
.exo-locked {
    background: #fff3e0;
    border: 2px solid var(--exo-warning);
    border-radius: 10px;
    padding: 15px;
    text-align: center;
    color: #e65100;
    font-weight: bold;
}

/* Pastilles de statut de session */
.exo-badge { display: inline-flex; align-items: center; gap: 6px; padding: 8px 16px; border-radius: 20px; font-weight: 600; font-size: 0.9em; }
.exo-badge-done { background: #e8f5e9; color: #388e3c; border: 2px solid #388e3c; }
.exo-badge-todo { background: #e3f2fd; color: #1976d2; border: 2px solid #1976d2; }
.exo-badge-current { background: var(--exo-gradient); color: white; border: 2px solid var(--exo-primary); }

@media (max-width: 600px) {
    .exo-header { flex-direction: column; align-items: flex-start; }
}