:root {
    --bg-color: #f0f4f8;
    --card-bg: #ffffff;
    --text-main: #1e293b;
    --text-muted: #64748b;
    --primary: #4f46e5;
    --primary-hover: #4338ca;
    --success: #10b981;
    --success-bg: #d1fae5;
    --success-text: #065f46;
    --danger: #f43f5e;
    --danger-bg: #ffe4e6;
    --danger-text: #9f1239;
    --border: #cbd5e1;
    --shadow: 0 10px 25px -5px rgba(0, 0, 0, 0.05), 0 8px 10px -6px rgba(0, 0, 0, 0.05);
}

body {
    font-family: 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-main);
    margin: 0;
    padding: 0;
    line-height: 1.6;
}

.container { 
    max-width: 1000px; 
    margin: 40px auto; 
    padding: 0 20px; 
}

.small-container { 
    max-width: 650px; 
}

header { 
    text-align: center; 
    margin-bottom: 40px; 
}

header h1 { 
    font-size: 2.5rem; 
    color: var(--primary); 
    margin-bottom: 10px;
    font-weight: 800;
}

header p {
    color: var(--text-muted);
    font-size: 1.1rem;
}

/* Grid & Cards */
.grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 25px;
}

.card {
    background: var(--card-bg);
    border: none;
    border-radius: 20px;
    padding: 30px;
    box-shadow: var(--shadow);
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: 0 20px 25px -5px rgba(79, 70, 229, 0.1);
}

.card h3 {
    margin-top: 0;
    font-size: 1.4rem;
    color: var(--primary);
}

.btn-group { 
    display: flex; 
    flex-direction: column; 
    gap: 10px; 
    margin-top: 25px; 
}

/* Buttons */
.btn {
    background-color: var(--primary);
    color: white;
    padding: 14px 24px;
    border-radius: 14px;
    text-decoration: none;
    font-weight: 600;
    font-size: 1rem;
    border: none;
    cursor: pointer;
    text-align: center;
    transition: all 0.2s ease;
    box-shadow: 0 4px 6px -1px rgba(79, 70, 229, 0.2);
}

.btn:hover { 
    background-color: var(--primary-hover); 
    transform: translateY(-1px);
}

.btn-sm { 
    padding: 8px 16px; 
    font-size: 0.9rem; 
    border-radius: 10px;
}

.btn-outline { 
    background-color: transparent; 
    color: var(--primary); 
    border: 2px solid var(--primary); 
    box-shadow: none;
}

.btn-outline:hover { 
    background-color: #f0f0ff; 
}

.btn-success { background-color: var(--success); box-shadow: 0 4px 6px -1px rgba(16, 185, 129, 0.2); }
.btn-success:hover { background-color: #059669; }
.btn-danger { background-color: var(--danger); box-shadow: 0 4px 6px -1px rgba(244, 63, 94, 0.2); }
.btn-danger:hover { background-color: #e11d48; }
.btn-wide { width: 100%; display: block; box-sizing: border-box; }

/* Forms */
.form-group { margin-bottom: 25px; text-align: left; }
.form-group label { display: block; margin-bottom: 10px; font-weight: 600; color: var(--text-main); font-size: 1.05rem; }
.form-input {
    width: 100%;
    padding: 16px;
    border: 2px solid #e2e8f0;
    border-radius: 14px;
    box-sizing: border-box;
    font-size: 1.05rem;
    font-family: inherit;
    background-color: #f8fafc;
    transition: all 0.2s ease;
}
.form-input:focus { 
    border-color: var(--primary); 
    background-color: #fff;
    outline: none; 
    box-shadow: 0 0 0 4px rgba(79, 70, 229, 0.1);
}

/* Learning & Quiz Box */
.navigation-top { 
    display: flex; 
    justify-content: space-between; 
    margin-bottom: 20px; 
    color: var(--text-muted); 
    font-weight: 600;
}

.back-link { text-decoration: none; color: var(--primary); }

.learn-box, .result-box {
    background: var(--card-bg);
    border: none;
    border-radius: 24px;
    padding: 40px;
    box-shadow: var(--shadow);
    text-align: center;
}

.learn-box h2 {
    font-size: 1.8rem;
    margin-top: 15px;
    color: var(--text-main);
}

.badge { 
    background: #e0e7ff; 
    color: var(--primary); 
    padding: 6px 16px; 
    border-radius: 9999px; 
    font-size: 0.9rem; 
    font-weight: 700; 
    display: inline-block;
}

.alert-badge { background: #ffe4e6; color: var(--danger); }

hr { border: 0; border-top: 2px solid #f1f5f9; margin: 25px 0; }

.answer { 
    font-size: 1.2rem; 
    color: var(--text-main); 
    text-align: left; 
    background: #f8fafc; 
    padding: 20px; 
    border-radius: 16px; 
    border-left: 6px solid var(--primary);
}

.pagination { 
    display: flex; 
    justify-content: space-between; 
    margin-top: 30px; 
    align-items: center; 
}

/* Score & Results */
.score { 
    font-size: 4.5rem; 
    font-weight: 800; 
    color: var(--success); 
    margin: 20px 0; 
}

.success-msg { 
    color: var(--success); 
    background-color: var(--success-bg); 
    padding: 12px; 
    border-radius: 10px; 
    font-weight: bold; 
    margin-bottom: 20px; 
    text-align: center;
}