/* =========================================================
   ZENITH STUDY ENGINE — Jovan AI Premium (Zenith v3.0)
   ========================================================= */

.zenith-page {
    padding: var(--space-xl) var(--space-lg) 5rem;
    max-width: 1100px;
    margin: 0 auto;
}

.page-header h2 {
    font-size: 2.75rem;
    font-weight: 900;
    letter-spacing: -0.03em;
    background: linear-gradient(135deg, var(--text-header), var(--primary));
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

/* ── Selection Section ── */
.selection-section {
    background: rgba(255, 255, 255, 0.55);
    -webkit-backdrop-filter: blur(32px);
    backdrop-filter: blur(32px);
    padding: 2.5rem;
    border-radius: 32px;
    border: 1px solid rgba(255, 255, 255, 0.6);
    box-shadow: var(--shadow-premium);
    margin-bottom: 2.5rem;
}

.selectors-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 1.5rem;
}

.selector-group select {
    padding: 14px 18px;
    border-radius: 16px;
    border: 1.5px solid rgba(0, 0, 0, 0.05);
    font-size: 1rem;
    background: white;
    color: var(--text-main);
    font-weight: 700;
    transition: all 0.3s ease;
}

.selector-group select:focus {
    border-color: var(--primary);
    box-shadow: 0 0 0 5px var(--primary-light);
    outline: none;
}

/* ── Chapter Info Card ── */
.chapter-info-card {
    background: linear-gradient(135deg, rgba(108, 99, 255, 0.08), rgba(255, 255, 255, 0.6));
    -webkit-backdrop-filter: blur(24px);
    backdrop-filter: blur(24px);
    padding: 2.5rem;
    border-radius: 32px;
    border: 1px solid var(--primary-light);
    margin-bottom: 2.5rem;
    position: relative;
    overflow: hidden;
}

.chapter-info-card::after {
    content: '';
    position: absolute;
    top: -20px;
    right: -20px;
    width: 100px;
    height: 100px;
    background: var(--primary);
    filter: blur(40px);
    opacity: 0.1;
}

.info-header h3 {
    font-size: 2rem;
    font-weight: 900;
    color: var(--text-header);
    letter-spacing: -0.01em;
}

.badge {
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    color: white;
    padding: 6px 16px;
    border-radius: 100px;
    font-size: 0.75rem;
    font-weight: 900;
    box-shadow: 0 4px 12px rgba(108, 99, 255, 0.3);
}

/* ── Study Modes Nav ── */
.study-modes-nav {
    display: flex;
    gap: 1rem;
    margin-bottom: 3rem;
    overflow-x: auto;
    padding: 5px;
}

.mode-btn {
    padding: 12px 24px;
    background: rgba(255, 255, 255, 0.6);
    border-radius: 16px;
    border: 1px solid rgba(0, 0, 0, 0.03);
    font-size: 0.9rem;
    font-weight: 800;
    color: var(--text-muted);
    white-space: nowrap;
    transition: all 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    display: flex;
    align-items: center;
    gap: 10px;
}

.mode-btn:hover {
    transform: translateY(-2px);
    background: white;
    box-shadow: 0 8px 20px rgba(0,0,0,0.05);
    color: var(--primary);
}

.mode-btn.active {
    background: var(--primary);
    color: white;
    border-color: var(--primary);
    box-shadow: 0 8px 25px rgba(108, 99, 255, 0.3);
}

/* ── AI Box Content Area ── */
.ai-box {
    background: rgba(255, 255, 255, 0.5);
    -webkit-backdrop-filter: blur(32px);
    backdrop-filter: blur(32px);
    border-radius: 36px;
    padding: 3rem;
    box-shadow: var(--shadow-premium);
    border: 1px solid rgba(255, 255, 255, 0.6);
    line-height: 1.8;
}

.ai-header {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 2rem;
    padding-bottom: 1.5rem;
    border-bottom: 1px solid rgba(0,0,0,0.03);
}

.ai-icon { font-size: 2rem; }

.ai-header h4 {
    font-size: 1.5rem;
    font-weight: 900;
    color: var(--text-header);
    letter-spacing: -0.01em;
}

.ai-body h5 {
    font-size: 1.25rem;
    color: var(--text-header);
    font-weight: 900;
    margin: 2.5rem 0 1.25rem 0;
}

.ai-body p {
    font-size: 1.05rem;
    font-weight: 500;
    color: var(--text-main);
}

.ai-body ul {
    padding-left: 1.5rem;
}

.ai-body li {
    margin-bottom: 12px;
}

.ai-action {
    margin-top: 3rem;
    border-top: 1px solid rgba(0,0,0,0.03);
    padding-top: 2rem;
}

@media (max-width: 600px) {
    .ai-box { padding: 1.75rem; }
    .ai-header h4 { font-size: 1.25rem; }
}