/* COLOR SCHEMES */
/* Original & Professional Themes Updated with --nav-text */
.theme-warmoat { --bg: #d9d2c5; --card-bg: #ede7db; --text: #333; --btn-bg: #333; --nav-bg: #333; --nav-text: #fff; }
.theme-forest { --bg: #2d3d2d; --card-bg: #3d523d; --text: #fff; --btn-bg: #1b261b; --nav-bg: #1b261b; --nav-text: #fff; }
.theme-blue { --bg: #1a2a3a; --card-bg: #253b52; --text: #fff; --btn-bg: #0d161f; --nav-bg: #0d161f; --nav-text: #fff; }
.theme-midnight { --bg: #0f172a; --card-bg: #1e293b; --text: #f8fafc; --btn-bg: #334155; --nav-bg: #020617; --nav-text: #fff; }
.theme-sage { --bg: #e2e8f0; --card-bg: #ffffff; --text: #1e293b; --btn-bg: #475569; --nav-bg: #1e293b; --nav-text: #fff; }
.theme-champagne { --bg: #f5f5f4; --card-bg: #fafaf9; --text: #44403c; --btn-bg: #78716c; --nav-bg: #44403c; --nav-text: #fff; }
.theme-graphite { --bg: #1c1c1c; --card-bg: #2d2d2d; --text: #e0e0e0; --btn-bg: #4a4a4a; --nav-bg: #000000; --nav-text: #fff; }

/* FIXED: Soft Minimalist now uses dark text for the light nav */
.theme-minimalist { --bg: #ffffff; --card-bg: #fcfcfc; --text: #111111; --btn-bg: #111111; --nav-bg: #f3f4f6; --nav-text: #111; }

/* NEW PREMIUM PROFESSIONAL SCHEMES */
.theme-emerald { --bg: #064e3b; --card-bg: #065f46; --text: #ecfdf5; --btn-bg: #022c22; --nav-bg: #022c22; --nav-text: #fff; }
.theme-corporate { --bg: #f1f5f9; --card-bg: #ffffff; --text: #0f172a; --btn-bg: #2563eb; --nav-bg: #1e3a8a; --nav-text: #fff; }
.theme-charcoal-gold { --bg: #171717; --card-bg: #262626; --text: #f5f5f5; --btn-bg: #a16207; --nav-bg: #0a0a0a; --nav-text: #eab308; }
.theme-nordic { --bg: #f8fafc; --card-bg: #ffffff; --text: #334155; --btn-bg: #64748b; --nav-bg: #f1f5f9; --nav-text: #334155; }

/* Other original themes updated */
.theme-purple { --bg: #2e1a3a; --card-bg: #3f2552; --text: #fff; --btn-bg: #190d1f; --nav-bg: #190d1f; --nav-text: #fff; }
.theme-orange { --bg: #3e2723; --card-bg: #4e342e; --text: #fff; --btn-bg: #261b18; --nav-bg: #261b18; --nav-text: #fff; }
.theme-teal { --bg: #004d40; --card-bg: #00695c; --text: #fff; --btn-bg: #002e26; --nav-bg: #002e26; --nav-text: #fff; }
.theme-rose { --bg: #880e4f; --card-bg: #ad1457; --text: #fff; --btn-bg: #4a072b; --nav-bg: #4a072b; --nav-text: #fff; }
.theme-slate { --bg: #263238; --card-bg: #37474f; --text: #fff; --btn-bg: #10161a; --nav-bg: #10161a; --nav-text: #fff; }
.theme-wine { --bg: #4a0000; --card-bg: #630000; --text: #fff; --btn-bg: #2e0000; --nav-bg: #2e0000; --nav-text: #fff; }
.theme-indigo { --bg: #1a237e; --card-bg: #283593; --text: #fff; --btn-bg: #0d1240; --nav-bg: #0d1240; --nav-text: #fff; }

body { 
    margin: 0; 
    font-family: 'Segoe UI', sans-serif; 
    background-color: var(--bg); 
    color: var(--text); 
    transition: 0.4s; 
}

/* TOP NAV LAYOUT - Updated to use --nav-text */
.top-nav { 
    display: flex; 
    justify-content: space-between; 
    align-items: center; 
    padding: 15px 40px; 
    background-color: var(--nav-bg); 
    color: var(--nav-text); 
}
.nav-links { display: flex; list-style: none; gap: 30px; margin: 0; padding: 0; }
.nav-links li { cursor: pointer; font-weight: bold; position: relative; color: var(--nav-text); }
.nav-links a { text-decoration: none; color: inherit; }

/* SIDEBAR LAYOUT */
.main-container { display: flex; padding: 25px; gap: 30px; }
.sidebar { width: 240px; }
.sidebar-card { 
    background: var(--card-bg); 
    padding: 20px; 
    border-radius: 15px; 
    box-shadow: 0 4px 10px rgba(0,0,0,0.1); 
}
.side-links { list-style: none; padding: 0; }
.side-links li { 
    padding: 12px; 
    margin-bottom: 8px; 
    border: 1px solid var(--text); 
    border-radius: 8px; 
    cursor: pointer; 
    position: relative; 
}

/* DROPDOWN LOGIC */
.dropdown:hover .submenu, .dropdown-side:hover .submenu-side { display: block; }
.submenu, .submenu-side { 
    display: none; 
    position: absolute; 
    background: white; 
    color: #333; 
    padding: 10px; 
    border-radius: 8px; 
    min-width: 150px; 
    z-index: 100; 
    box-shadow: 0 8px 20px rgba(0,0,0,0.2); 
}
.submenu li a, .submenu-side li a { color: #333; text-decoration: none; display: block; padding: 5px 0; }

/* SUBJECT GRID */
.content { flex-grow: 1; text-align: center; }
.card-grid { 
    display: grid; 
    grid-template-columns: 1fr 1fr; 
    gap: 30px; 
}

/* PROFESSIONAL CARD STYLE */
.subject-card {
    background-color: var(--card-bg);
    padding: 30px;
    border-radius: 22px;
    box-shadow: 0 6px 20px rgba(0,0,0,0.1);
    text-align: left;
    border: 1px solid rgba(255,255,255,0.05);
}
.subject-title { 
    font-size: 1.6rem; 
    margin: 0 0 20px 0; 
    border-bottom: 1px solid rgba(0,0,0,0.1); 
    padding-bottom: 12px; 
}

/* BUTTONS */
.button-stack { display: flex; flex-direction: column; gap: 12px; }
.math-btn {
    background-color: var(--btn-bg);
    color: white;
    text-decoration: none;
    text-align: center;
    padding: 15px;
    border-radius: 12px;
    font-weight: bold;
    text-transform: uppercase;
    font-size: 0.85rem;
    transition: 0.2s;
}
.math-btn:hover { opacity: 0.8; transform: translateY(-2px); }