/* --- HERTA LIGHT & MODERN THEME --- */
:root {
    --herta-main: #6c5ce7;    
    --herta-dark: #4834d4;   
    --herta-gold: #fdcb6e;    
    --herta-accent: #a29bfe;  
    --bg-color: #f4f7f6;      
    --card-bg: #ffffff;
    --text-main: #2d3436;
    --text-muted: #636e72;
    --success: #00b894;
    --danger: #ff7675;
}

@import url('https://fonts.googleapis.com/css2?family=Poppins:wght@300;400;500;600;700&display=swap');

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Poppins', sans-serif; 
}

body {
    background-color: var(--bg-color);
    background-image: radial-gradient(#dfe6e9 1.5px, transparent 1.5px);
    background-size: 24px 24px; 
    color: var(--text-main);
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

header {
    background: #e1d8ff;
    color: var(--herta-dark);
    text-align: center;
    padding: 1.5rem 1rem;
    box-shadow: 0 4px 20px rgba(0,0,0,0.05); 
    border-bottom: 3px solid var(--herta-main);
    position: relative;
    z-index: 10;
}

header h1 {
    font-size: 2.2rem;
    font-weight: 700;
    color: var(--herta-main);
    letter-spacing: 1px;
    margin-bottom: 0.5rem;
}

header p {
    color: var(--text-muted);
    font-size: 1rem;
}

.menu-container {
    flex: 1; 
    display: flex;
    justify-content: center;
    align-items: center;
    flex-wrap: wrap; 
    padding: 2rem;
    gap: 2rem; 
}

.card {
    background: var(--card-bg);
    width: 300px;
    padding: 2rem;
    border-radius: 20px; 
    box-shadow: 0 10px 25px rgba(0,0,0,0.05);
    cursor: pointer; 
    transition: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1);
    border: 2px solid transparent;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
}

.card:hover {
    transform: translateY(-8px); 
    box-shadow: 0 15px 35px rgba(108, 92, 231, 0.15); 
    border-color: var(--herta-accent);
}

.card h2 {
    margin-bottom: 1rem;
    color: var(--herta-dark);
    font-size: 1.4rem;
}

.card p {
    color: var(--text-muted);
    margin-bottom: 1.5rem;
    line-height: 1.6;
    font-size: 0.95rem;
}

.tag {
    display: inline-block;
    padding: 6px 12px;
    border-radius: 12px;
    font-size: 0.75rem;
    font-weight: 600;
    margin-right: 5px;
    margin-bottom: 5px;
    text-transform: uppercase;
}


.language { 
    background-color: #E3F2FD; 
    color: #1565C0;            
}

.math { 
    background-color: #FFEBEE; 
    color: #C62828;           
}

.tech { 
    background-color: #F3E5F5; 
    color: #6A1B9A;            
}

.biology { 
    background-color: #E8F5E9; 
    color: #2E7D32;            
}

.physics { 
    background-color: #FFF9C4; 
    color: #F57F17;           
}

.chemestry { 
    background-color: #d6fef3; 
    color: #90dcfd;            
}


.card.locked {
    opacity: 0.6;
    background-color: #f1f2f6;
    cursor: not-allowed;
    box-shadow: none;
}
.card.locked:hover { transform: none; }

footer {
    text-align: center;
    padding: 1.5rem;
    background-color: white;
    color: var(--text-muted);
    font-size: 0.9rem;
    border-top: 1px solid #eee;
}

button {
    background-color: var(--herta-main);
    color: white;
    border: none;
    padding: 12px 24px;
    border-radius: 12px;
    cursor: pointer;
    font-weight: 600;
    font-size: 0.95rem;
    transition: all 0.2s;
    box-shadow: 0 4px 10px rgba(108, 92, 231, 0.2);
}

button:hover {
    background-color: var(--herta-dark);
    transform: translateY(-2px);
    box-shadow: 0 6px 15px rgba(108, 92, 231, 0.3);
}

button:active { transform: translateY(0); }

input, select {
    padding: 12px 15px;
    border: 2px solid #dfe6e9;
    border-radius: 10px;
    width: 100%;
    margin-bottom: 10px;
    transition: border-color 0.3s;
    font-size: 0.95rem;
    background: #fff;
}

input:focus, select:focus {
    border-color: var(--herta-main);
    outline: none;
}

@media (max-width: 600px) {
    header h1 { font-size: 1.8rem; }
    .card { width: 100%; }
    .menu-container { padding: 1rem; }
}