/* =========================================
   VARIABLES CYBERPUNK & NÉON (MODE SOMBRE PAR DÉFAUT)
========================================= */
:root {
    --font-family: 'Exo 2', 'Poppins', sans-serif;

    --bg-deep: #030307;
    --card-bg: rgba(20, 22, 30, 0.35);
    --card-border: rgba(255, 255, 255, 0.08);
    --card-border-hover: rgba(0, 240, 255, 0.4);
    
    --primary-accent: #00f0ff; /* Cyan Néon */
    --secondary-accent: #7000ff; /* Violet Profond */
    
    --text-main: #f8fafc;
    --text-muted: #94a3b8;
    
    --glass-blur: blur(20px);
    --neon-glow: 0 8px 32px rgba(0, 240, 255, 0.25);

    /* Couleurs de validation façon jeu d'arcade */
    --success-color-bg: rgba(57, 255, 20, 0.2); /* Vert Néon transparent */
    --error-color-bg: rgba(255, 0, 127, 0.2);   /* Rose Néon transparent */
    --missing-color-bg: rgba(252, 232, 3, 0.2); /* Jaune Néon transparent */
    
    --sum-success: #39ff14;
    --sum-error: #ff007f;
}

/* =========================================
   RESET & BASE
========================================= */
*, *::before, *::after {
    box-sizing: border-box;
}

body {
    font-family: var(--font-family);
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    margin: 0;
    padding: 20px;
    background-color: var(--bg-deep);
    color: var(--text-main);
    /* Effet d'arrière-plan ambiant subtil */
    background-image: radial-gradient(circle at top left, rgba(112, 0, 255, 0.15), transparent 40%),
                      radial-gradient(circle at bottom right, rgba(0, 240, 255, 0.15), transparent 40%);
    transition: background-color 0.5s ease, color 0.5s ease, background-image 0.5s ease;
}

/* =========================================
   CONTENEUR PRINCIPAL (GLASSMORPHISM)
========================================= */
.app-container {
    width: 100%;
    max-width: 600px;
    padding: 30px;
    border-radius: 24px;
    background: var(--card-bg);
    backdrop-filter: var(--glass-blur);
    -webkit-backdrop-filter: var(--glass-blur);
    border: 1px solid var(--card-border);
    box-shadow: 0 25px 60px rgba(0, 0, 0, 0.8), var(--neon-glow);
    transition: all 0.4s ease;
}

.app-container:hover {
    border-color: var(--card-border-hover);
}

/* =========================================
   HEADER & TYPOGRAPHIE
========================================= */
.app-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 25px;
    border-bottom: 1px solid var(--card-border);
    padding-bottom: 15px;
    transition: border-color 0.4s ease;
}

h1 {
    font-size: 2.2rem;
    font-weight: 800;
    margin: 0;
    text-transform: uppercase;
    letter-spacing: 2px;
    background: linear-gradient(to right, #fff, var(--primary-accent), var(--secondary-accent));
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    text-shadow: 0 0 20px rgba(0, 240, 255, 0.2);
}

/* =========================================
   CONTRÔLES & BOUTONS
========================================= */
.controls {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    align-items: center;
    gap: 15px;
    margin-bottom: 25px;
}

.control-group {
    display: flex;
    align-items: center;
    gap: 10px;
}

.control-group label {
    font-weight: 600;
    color: var(--text-muted);
    text-transform: uppercase;
    font-size: 0.85rem;
    letter-spacing: 1px;
}

.btn, select, input[type="number"], .theme-button {
    font-family: var(--font-family);
    font-size: 1rem;
    font-weight: 600;
    padding: 10px 20px;
    border-radius: 8px;
    border: 1px solid var(--card-border);
    cursor: pointer;
    transition: all 0.3s ease;
    text-align: center;
    background: rgba(255, 255, 255, 0.05);
    color: var(--text-main);
    outline: none;
}

/* Bouton Primaire avec effet dégradé */
.btn-primary { 
    background: linear-gradient(45deg, rgba(0, 240, 255, 0.2), rgba(112, 0, 255, 0.2));
    border: 1px solid var(--primary-accent);
    text-transform: uppercase;
    letter-spacing: 1px;
}

.btn-secondary { 
    background: rgba(255, 255, 255, 0.05); 
}

.btn:hover, select:hover, input[type="number"]:hover, .theme-button:hover {
    transform: translateY(-2px);
    border-color: var(--primary-accent);
    box-shadow: 0 0 15px rgba(0, 240, 255, 0.3);
}

.theme-button {
    font-size: 1.5rem;
    padding: 5px 10px;
    background: transparent;
    border: none;
}

.theme-button:hover {
    color: var(--primary-accent);
    text-shadow: 0 0 10px var(--primary-accent);
    box-shadow: none;
}

/* Fix pour les options du menu déroulant */
select option {
    background-color: #0a0c12; /* Fond sombre forcé */
    color: #ffffff; /* Texte blanc forcé */
}

/* Inputs / Selects */
select, input[type="number"] {
    -webkit-appearance: none;
    -moz-appearance: none;
    appearance: none;
}

select:focus, input[type="number"]:focus {
    border-color: var(--primary-accent);
    background: rgba(0, 240, 255, 0.05);
    box-shadow: inset 0 0 10px rgba(0, 240, 255, 0.1);
}

input[type="number"]#prefill-input {
    width: 70px;
}

#numbers-info {
    text-align: center;
    margin-bottom: 25px;
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--primary-accent);
    text-shadow: 0 0 10px rgba(0, 240, 255, 0.3);
}

/* =========================================
   GRILLE DU JEU (GAME BOARD)
========================================= */
#game-board {
    display: grid;
    margin: 0 auto;
    border: 2px solid var(--primary-accent);
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 0 20px rgba(0, 240, 255, 0.15);
    background: rgba(10, 12, 18, 0.8);
    transition: all 0.4s ease;
}

.cell, .sum-cell {
    width: 50px;
    height: 50px;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 1.2rem;
    border: 1px solid rgba(0, 240, 255, 0.2);
    transition: border-color 0.4s ease;
}

/* Cellules modifiables */
.cell input {
    width: 100%;
    height: 100%;
    text-align: center;
    border: none;
    font-size: 1.3rem;
    font-weight: 700;
    padding: 0;
    background-color: transparent;
    color: var(--text-main);
    font-family: 'Exo 2', sans-serif;
    transition: color 0.3s ease, background-color 0.3s ease;
}

.cell input:focus {
    outline: none;
    box-shadow: inset 0 0 0 2px var(--primary-accent), inset 0 0 15px rgba(0, 240, 255, 0.3);
    background: rgba(0, 240, 255, 0.05);
}

/* États des cases (Pré-remplies, Correct, Incorrect) */
.cell input.prefilled {
    color: var(--text-muted);
    pointer-events: none;
    background: rgba(255, 255, 255, 0.02);
}

.cell input.correct-answer { 
    background-color: var(--success-color-bg) !important; 
    color: var(--sum-success) !important; 
    text-shadow: 0 0 10px var(--sum-success);
}

.cell input.incorrect-answer { 
    background-color: var(--error-color-bg) !important; 
    color: var(--sum-error) !important; 
    text-shadow: 0 0 10px var(--sum-error);
}

.cell input.missing-answer { 
    background-color: var(--missing-color-bg) !important; 
    color: #fce803 !important; 
    text-shadow: 0 0 10px #fce803;
}

/* Désactiver les flèches des inputs number */
input[type="number"]::-webkit-outer-spin-button,
input[type="number"]::-webkit-inner-spin-button {
    -webkit-appearance: none;
    margin: 0;
}
input[type="number"] { -moz-appearance: textfield; }

/* =========================================
   CELLULES DE SOMME (BORDURES)
========================================= */
.sum-cell {
    font-weight: 800;
    font-family: 'Exo 2', sans-serif;
    background: rgba(112, 0, 255, 0.15); /* Fond légèrement violet */
    color: var(--primary-accent);
}

.sum-cell.correct { 
    color: var(--sum-success) !important; 
    text-shadow: 0 0 10px rgba(57, 255, 20, 0.5);
}

.sum-cell.incorrect { 
    color: var(--sum-error) !important; 
    text-shadow: 0 0 10px rgba(255, 0, 127, 0.5);
}

/* =========================================
   MODE CLAIR (LIGHT GLASSMORPHISM)
========================================= */
body.light-mode {
    --bg-deep: #f0f4f9; /* Gris bleuté très clair */
    --card-bg: rgba(255, 255, 255, 0.65); /* Verre blanc transparent */
    --card-border: rgba(0, 0, 0, 0.1);
    --card-border-hover: rgba(0, 136, 255, 0.4);
    
    --primary-accent: #0077ff; /* Bleu électrique */
    --secondary-accent: #6200ee; /* Violet profond */
    
    --text-main: #121212; /* Texte foncé pour la lisibilité */
    --text-muted: #64748b;
    
    --neon-glow: 0 8px 32px rgba(0, 119, 255, 0.15);

    --success-color-bg: rgba(76, 175, 80, 0.2);
    --error-color-bg: rgba(244, 67, 54, 0.2);
    --missing-color-bg: rgba(255, 193, 7, 0.3);
    
    --sum-success: #2e7d32;
    --sum-error: #c62828;
    
    background-image: radial-gradient(circle at top left, rgba(98, 0, 238, 0.08), transparent 40%),
                      radial-gradient(circle at bottom right, rgba(0, 119, 255, 0.08), transparent 40%);
}

/* Ajustements spécifiques pour le mode clair */
body.light-mode h1 {
    background: linear-gradient(to right, #121212, var(--primary-accent), var(--secondary-accent));
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    text-shadow: 0 0 15px rgba(0, 119, 255, 0.1);
}

body.light-mode select option {
    background-color: #ffffff; /* Fond clair pour les options en mode jour */
    color: #121212;
}

body.light-mode .btn, 
body.light-mode select, 
body.light-mode input[type="number"], 
body.light-mode .theme-button {
    background: rgba(255, 255, 255, 0.5);
    color: var(--text-main);
    border-color: rgba(0, 0, 0, 0.1);
}

body.light-mode .btn-primary {
    background: linear-gradient(45deg, var(--primary-accent), var(--secondary-accent));
    color: white;
    border: none;
}

body.light-mode #game-board {
    background: rgba(255, 255, 255, 0.8);
    border-color: var(--primary-accent);
}

body.light-mode .cell, 
body.light-mode .sum-cell {
    border-color: rgba(0, 0, 0, 0.08);
}

body.light-mode .cell input.prefilled {
    background: rgba(0, 0, 0, 0.03);
    color: var(--text-muted);
}