/* ==========================================================================
   GLOBAL & LAYOUT STYLES
   ========================================================================== */
body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: #0b132b;
    color: #ffffff;
    max-width: 950px;
    margin: 40px auto;
    padding: 15px;
}

.adventure-card, .portal-card {
    background: #1c2541;
    border-radius: 20px;
    box-shadow: 0 12px 36px rgba(0, 0, 0, 0.6);
    overflow: hidden;
    border: 1px solid #3a506b;
    margin: 0 auto;
}

/* ==========================================================================
   HEADER BANNER
   ========================================================================== */
.header-banner {
    background: linear-gradient(135deg, #131c31, #1c2541);
    padding: 30px 20px;
    text-align: center;
    border-bottom: 2px solid #2a3a5e;
}

.header-banner h1 {
    margin: 0;
    font-size: 32px;
    color: #ffffff;
}

.subtitle {
    margin-top: 8px;
    margin-bottom: 0;
    color: #00cec9;
    font-size: 16px;
}

/* ==========================================================================
   SUBJECT GRID & CARDS (MAIN HUB & TYPING ARCADE)
   ========================================================================== */
.content {
    padding: 30px;
}

.link-grid, .subject-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 20px;
}

.nav-btn, .subject-card {
    border-radius: 16px;
    padding: 25px 15px;
    text-decoration: none;
    color: #ffffff;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    text-align: center;
    min-height: 140px;
}

.nav-btn:hover, .subject-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.4);
}

.nav-btn span, .subject-card h2 {
    font-size: 22px;
    font-weight: bold;
    margin: 0;
}

/* SVG & Icon Container Sizing */
.btn-icon, .card-icon {
    width: 60px;
    height: 60px;
    margin-bottom: 12px;
    display: flex;
    justify-content: center;
    align-items: center;
}

.btn-icon svg, .card-icon svg {
    width: 100%;
    height: 100%;
    display: block;
}

/* ==========================================================================
   INDIVIDUAL SUBJECT COLOR THEMES
   ========================================================================== */
/* Bible Topic Styling */
.bible-btn, .subject-card.bible { 
    background: #16a085; 
}

/* Math Topic Styling */
.math-btn, .subject-card.math { 
    background: #e67e22; 
}

/* History Topic Styling */
.history-btn, .subject-card.history { 
    background: #8e44ad; 
}

/* Science Topic Styling */
.science-btn, .subject-card.science { 
    background: #2ecc71; 
}

/* Typing Topic Styling */
.typing-btn, .subject-card.typing { 
    background: #2980b9; 
}

/* ==========================================================================
   FOOTER & RETURN NAVIGATION
   ========================================================================== */
.footer-navigation {
    margin-top: 30px;
    padding-top: 20px;
    border-top: 2px solid #2a3a5e;
    text-align: center;
}

.back-to-hub-btn {
    display: inline-block;
    color: #00cec9;
    text-decoration: none;
    font-weight: bold;
    font-size: 16px;
    padding: 10px 24px;
    border: 2px solid #00cec9;
    border-radius: 10px;
    transition: all 0.2s ease;
}

.back-to-hub-btn:hover {
    background: #00cec9;
    color: #0d1b2a;
}

/* ==========================================================================
   RESPONSIVE LAYOUT ADJUSTMENTS
   ========================================================================== */
@media (max-width: 768px) {
    .link-grid, .subject-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 480px) {
    .link-grid, .subject-grid {
        grid-template-columns: 1fr;
    }
}