/* =========================================================
   BUGHUNT: PYTHON CODEX & STUDY ACADEMY STYLESHEET (css/study.css)
   Ultra-clean, polished, cyber-arcade UI for mastering Python
   ========================================================= */

/* =========================================================
   1. CODEX SCREEN ROOT & AMBIENT BACKDROP
   ========================================================= */
#codex-screen {
    display: none;
    position: fixed;
    inset: 0;
    width: 100vw;
    height: 100vh;
    box-sizing: border-box;
    padding: 14px clamp(12px, 2vw, 28px);
    background:
        radial-gradient(circle at 50% 12%, rgba(34, 7, 50, 0.88) 0%, rgba(13, 1, 23, 0.96) 55%, #05000a 100%),
        url("bgassets/mainmenu.png") center/cover no-repeat;
    color: #f0e6f6;
    font-family: 'Inter', system-ui, -apple-system, sans-serif;
    z-index: 120;
    flex-direction: column;
    overflow: hidden;
}

#codex-screen:not([style*="display: none"]),
#codex-screen[style*="display: block"],
#codex-screen[style*="display: flex"] {
    display: flex !important;
}

/* Cyber ambient vignette overlay */
#codex-screen::before {
    content: "";
    position: absolute;
    inset: 0;
    background: radial-gradient(circle at 50% 50%, rgba(130, 0, 180, 0.08), transparent 55%);
    box-shadow: inset 0 0 160px rgba(0, 0, 0, 0.94);
    pointer-events: none;
    z-index: 1;
}

/* Subtle arcade scanlines */
#codex-screen::after {
    content: "";
    position: absolute;
    inset: 0;
    background: repeating-linear-gradient(
        0deg,
        rgba(255, 255, 255, 0.015) 0px,
        rgba(255, 255, 255, 0.015) 1px,
        transparent 1px,
        transparent 5px
    );
    opacity: 0.3;
    pointer-events: none;
    z-index: 1;
}

/* =========================================================
   2. TOP NAVIGATION HEADER (FLEX 3-ZONE LAYOUT - NO OVERLAP)
   ========================================================= */
.codex-header {
    position: relative;
    z-index: 10;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 14px;
    width: 100%;
    height: 62px;
    min-height: 62px;
    flex-shrink: 0;
    padding: 0 16px;
    background: var(--theme-card-bg, rgba(22, 12, 42, 0.88));
    backdrop-filter: blur(12px);
    border: 1px solid var(--theme-border, rgba(168, 85, 247, 0.4));
    border-radius: 10px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.5), 0 0 15px var(--theme-glow-soft, rgba(168, 85, 247, 0.12));
    box-sizing: border-box;
}

/* Back Button */
.codex-back-btn {
    display: flex;
    align-items: center;
    gap: 8px;
    height: 38px;
    padding: 0 16px;
    font-family: 'Press Start 2P', monospace;
    font-size: 14px;
    color: var(--theme-text-title, #e5b3ff);
    background: var(--theme-btn-deck-bg, linear-gradient(135deg, rgba(32, 20, 52, 0.95), rgba(16, 10, 30, 0.98)));
    border: 1.5px solid var(--theme-border, #74368e);
    border-left: 4px solid var(--theme-primary, #a855f7);
    border-radius: 6px;
    cursor: pointer;
    box-shadow: 0 0 10px var(--theme-glow-soft, rgba(168, 85, 247, 0.25));
    transition: all 0.18s ease;
    flex-shrink: 0;
    user-select: none;
}

.codex-back-btn:hover {
    background: var(--theme-btn-hover-gradient, linear-gradient(135deg, rgba(55, 30, 95, 0.98), rgba(28, 16, 52, 0.98)));
    color: #ffffff;
    border-color: var(--theme-accent, #ba68c8);
    box-shadow: 0 0 16px var(--theme-glow, rgba(212, 0, 255, 0.5));
    transform: translateY(-1px);
}

.codex-back-btn:active {
    transform: translateY(1px);
}

/* Center Titles */
.codex-header-titles {
    text-align: center;
    flex: 1 1 auto;
    min-width: 0;
    padding: 0 10px;
}

.codex-title {
    margin: 0;
    font-family: 'Press Start 2P', monospace;
    font-size: clamp(14px, 1.5vw, 19px);
    letter-spacing: 2px;
    color: #f8fafc;
    text-shadow:
        2px 2px 0 #1e0938,
        0 2px 10px rgba(0, 0, 0, 0.85),
        0 0 8px rgba(168, 85, 247, 0.35);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.codex-subtitle {
    margin: 4px 0 0 0;
    font-family: 'JetBrains Mono', monospace;
    font-size: clamp(10px, 0.85vw, 11px);
    color: #c4b5fd;
    letter-spacing: 1px;
    text-transform: uppercase;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

/* Right Actions (Search & Lang Switch) */
.codex-header-actions {
    display: flex;
    align-items: center;
    gap: 12px;
    flex-shrink: 0;
}

.codex-search-box {
    display: flex;
    align-items: center;
    background: rgba(14, 8, 26, 0.95);
    border: 1px solid #5a388a;
    border-radius: 20px;
    padding: 0 12px;
    width: clamp(180px, 18vw, 260px);
    height: 36px;
    box-shadow: inset 0 2px 6px rgba(0, 0, 0, 0.7);
    transition: border-color 0.2s, box-shadow 0.2s;
    box-sizing: border-box;
}

.codex-search-box:focus-within {
    border-color: #00f0ff;
    box-shadow: 0 0 12px rgba(0, 240, 255, 0.35), inset 0 2px 6px rgba(0, 0, 0, 0.8);
}

.codex-search-icon {
    font-size: 13px;
    margin-right: 8px;
    color: #a47bb8;
}

#codex-search-input {
    background: transparent;
    border: none;
    outline: none;
    color: #f7e6ff;
    font-family: 'Inter', sans-serif;
    font-size: 12px;
    width: 100%;
}

#codex-search-input::placeholder {
    color: #7d5493;
}

.codex-search-clear-btn {
    background: none;
    border: none;
    color: #a47bb8;
    font-size: 12px;
    cursor: pointer;
    padding: 0 4px;
    margin-left: 4px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    transition: color 0.15s, transform 0.15s;
}

.codex-search-clear-btn:hover {
    color: #ff3366;
    transform: scale(1.15);
}

/* =========================================================
   3. DIFFICULTY TABS (SEGMENTED TOP BAR)
   ========================================================= */
.codex-tabs-bar {
    position: relative;
    z-index: 10;
    display: flex;
    justify-content: center;
    max-width: 880px;
    margin: 8px auto 0 auto;
    width: 100%;
    gap: 10px;
    height: 42px;
    min-height: 42px;
    flex-shrink: 0;
}

.codex-tab {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    background: rgba(20, 10, 36, 0.85);
    border: 1px solid #4a1961;
    border-radius: 8px;
    font-family: 'Press Start 2P', monospace;
    font-size: 13.5px;
    color: #bfa4ce;
    cursor: pointer;
    transition: all 0.18s cubic-bezier(0.16, 1, 0.3, 1);
    box-shadow: inset 0 0 10px rgba(0, 0, 0, 0.6), 0 3px 10px rgba(0, 0, 0, 0.4);
    user-select: none;
}

.codex-tab .tab-sub {
    font-family: 'Inter', sans-serif;
    font-size: 11px;
    font-weight: 500;
    color: #8c60a2;
}

.codex-tab:hover {
    background: rgba(42, 16, 68, 0.95);
    border-color: #8e3eb5;
    color: #ffffff;
    transform: translateY(-1px);
}

.codex-tab.active {
    color: #ffffff;
    font-weight: bold;
    transform: translateY(-1px);
}

.codex-tab.active[data-diff="easy"] {
    background: linear-gradient(180deg, rgba(20, 70, 45, 0.9), rgba(8, 28, 16, 0.95));
    border-color: #38ef7d;
    box-shadow: 0 0 14px rgba(56, 239, 125, 0.35);
}
.codex-tab.active[data-diff="easy"] .tab-sub { color: #8ef7b5; }

.codex-tab.active[data-diff="normal"] {
    background: linear-gradient(180deg, rgba(15, 60, 100, 0.9), rgba(5, 20, 40, 0.95));
    border-color: #00f0ff;
    box-shadow: 0 0 14px rgba(0, 240, 255, 0.35);
}
.codex-tab.active[data-diff="normal"] .tab-sub { color: #85f3ff; }

.codex-tab.active[data-diff="hard"] {
    background: linear-gradient(180deg, rgba(85, 15, 100, 0.9), rgba(30, 4, 40, 0.95));
    border-color: #d400ff;
    box-shadow: 0 0 14px rgba(212, 0, 255, 0.35);
}
.codex-tab.active[data-diff="hard"] .tab-sub { color: #f4b0ff; }

.codex-tab.active[data-diff="hell"] {
    background: linear-gradient(180deg, rgba(110, 15, 30, 0.9), rgba(40, 4, 10, 0.95));
    border-color: #ff3366;
    box-shadow: 0 0 14px rgba(255, 51, 102, 0.35);
}
.codex-tab.active[data-diff="hell"] .tab-sub { color: #ff99aa; }

.tab-indicator {
    font-size: 11px;
}
.easy-indicator { color: #38ef7d; }
.normal-indicator { color: #00f0ff; }
.hard-indicator { color: #d400ff; }
.hell-indicator { color: #ff3366; }

/* =========================================================
   4. CODEX MAIN BODY & TWO-PANE LAYOUT
   ========================================================= */
.codex-body {
    position: relative;
    z-index: 10;
    display: flex;
    flex-direction: row;
    gap: 14px;
    margin-top: 10px;
    flex: 1 1 0;
    min-height: 0;
    width: 100%;
    overflow: hidden;
    box-sizing: border-box;
}

/* =========================================================
   5. LEFT SIDEBAR & TOPIC LIST
   ========================================================= */
.codex-sidebar {
    width: clamp(270px, 26vw, 360px);
    height: 100%;
    max-height: 100%;
    min-height: 0;
    flex-shrink: 0;
    display: flex;
    flex-direction: column;
    background: var(--theme-card-bg, rgba(18, 9, 34, 0.92));
    backdrop-filter: blur(12px);
    border: 1px solid var(--theme-border, rgba(168, 85, 247, 0.4));
    border-radius: 10px;
    box-shadow: 0 6px 24px rgba(0, 0, 0, 0.6), 0 0 15px var(--theme-glow-soft, rgba(168, 85, 247, 0.12));
    overflow: hidden;
    box-sizing: border-box;
}

.codex-sidebar-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 38px;
    min-height: 38px;
    flex-shrink: 0;
    padding: 0 14px;
    background: var(--theme-card-bg-subtle, rgba(12, 5, 22, 0.85));
    border-bottom: 1px solid var(--theme-border-subtle, rgba(168, 85, 247, 0.25));
    font-family: 'Press Start 2P', monospace;
    font-size: 13px;
    color: var(--theme-text-title, #e5b3ff);
    box-sizing: border-box;
}

.codex-sidebar-hint {
    font-family: 'Inter', sans-serif;
    font-size: 11px;
    color: #a47bb8;
}

/* Sidebar Memory Match Toggle Button */
.codex-memory-toggle-btn {
    display: flex;
    align-items: center;
    gap: 10px;
    width: calc(100% - 16px);
    margin: 8px 8px 4px 8px;
    padding: 8px 12px;
    background: var(--theme-card-bg-subtle, linear-gradient(135deg, rgba(38, 12, 60, 0.95), rgba(18, 2, 30, 0.95)));
    border: 1.5px solid var(--theme-primary, #a855f7);
    border-radius: 8px;
    cursor: pointer;
    box-shadow: 0 0 12px var(--theme-glow-soft, rgba(168, 85, 247, 0.25));
    transition: all 0.2s cubic-bezier(0.16, 1, 0.3, 1);
    box-sizing: border-box;
    text-align: left;
    flex-shrink: 0;
}

.codex-memory-toggle-btn:hover {
    background: linear-gradient(135deg, rgba(65, 18, 102, 0.98), rgba(28, 4, 48, 0.98));
    border-color: #00f0ff;
    box-shadow: 0 0 16px rgba(0, 240, 255, 0.4);
    transform: translateY(-1px);
}

.codex-memory-toggle-btn.active {
    background: linear-gradient(135deg, rgba(80, 20, 120, 0.98), rgba(25, 4, 40, 0.98));
    border-color: #38ef7d;
    border-left: 5px solid #38ef7d;
    box-shadow: 0 0 18px rgba(56, 239, 125, 0.4);
}

.mem-toggle-icon {
    font-size: 22px;
    filter: drop-shadow(0 0 6px rgba(168, 85, 247, 0.6));
    flex-shrink: 0;
}

.mem-toggle-info {
    flex: 1;
    min-width: 0;
}

.mem-toggle-title {
    display: block;
    font-family: 'Press Start 2P', monospace;
    font-size: 13.5px;
    color: #f5e8ff;
    letter-spacing: 0.4px;
}

.mem-toggle-sub {
    display: block;
    font-size: 11.5px;
    color: #bfa4ce;
    margin-top: 3px;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.mem-toggle-badge {
    font-family: 'Press Start 2P', monospace;
    font-size: 12px;
    padding: 4px 7px;
    background: rgba(56, 239, 125, 0.15);
    color: #38ef7d;
    border: 1px solid #38ef7d;
    border-radius: 4px;
    letter-spacing: 1px;
    box-shadow: 0 0 8px rgba(56, 239, 125, 0.3);
    flex-shrink: 0;
}

/* Scrollable Topic List (FLEX CONTAINER - NO FIXED CUTOFFS) */
.codex-topic-list {
    flex: 1 1 0;
    min-height: 0;
    overflow-y: auto;
    overscroll-behavior: contain;
    -webkit-overflow-scrolling: touch;
    scrollbar-width: thin;
    scrollbar-color: #6d28d9 rgba(6, 0, 12, 0.8);
    padding: 8px;
    display: flex;
    flex-direction: column;
    gap: 8px;
    box-sizing: border-box;
}

/* Individual Topic Item */
.codex-topic-card {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 9px 12px;
    background: linear-gradient(135deg, rgba(28, 14, 46, 0.85), rgba(16, 8, 28, 0.9));
    border: 1px solid #4a1961;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.16s ease;
    position: relative;
    flex-shrink: 0;
    box-sizing: border-box;
}

.codex-topic-card:hover {
    background: var(--theme-card-bg, linear-gradient(135deg, rgba(46, 20, 74, 0.95), rgba(24, 10, 42, 0.95)));
    border-color: var(--theme-primary, #a855f7);
    box-shadow: 0 4px 14px var(--theme-glow, rgba(168, 85, 247, 0.3));
    transform: translateX(2px);
}

.codex-topic-card.active {
    background: linear-gradient(90deg, rgba(65, 18, 98, 0.95), rgba(28, 8, 44, 0.95));
    border: 1px solid #00f0ff;
    border-left: 4px solid #00f0ff;
    box-shadow: 0 0 14px rgba(0, 240, 255, 0.3);
    transform: translateX(2px);
}

.topic-step-badge {
    font-family: 'JetBrains Mono', monospace;
    font-size: 12px;
    font-weight: 700;
    color: #a47bb8;
    background: rgba(0, 0, 0, 0.5);
    padding: 2px 5px;
    border-radius: 4px;
    border: 1px solid rgba(255, 255, 255, 0.08);
    flex-shrink: 0;
}

.codex-topic-card.active .topic-step-badge {
    color: #00f0ff;
    border-color: rgba(0, 240, 255, 0.4);
    background: rgba(0, 240, 255, 0.15);
}

.topic-sprite-thumb {
    width: 38px;
    height: 38px;
    flex-shrink: 0;
    object-fit: contain;
    image-rendering: pixelated;
    background: rgba(6, 0, 12, 0.7);
    border: 1px solid #4a1961;
    border-radius: 6px;
    padding: 2px;
}

.topic-sprite-thumb.fallback-icon {
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 18px;
    color: #ffd700;
}

.topic-info-wrap {
    flex: 1;
    min-width: 0;
}

.topic-card-category-row {
    display: flex;
    align-items: center;
    gap: 6px;
    margin-bottom: 2px;
}

.topic-card-category {
    font-size: 12.5px;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    color: #c084fc;
}

.topic-card-title {
    font-size: 13.5px;
    font-weight: 600;
    color: #f7e6ff;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    margin-bottom: 2px;
}

.topic-card-enemy {
    font-size: 11px;
    color: #d9a8ff;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    display: flex;
    align-items: center;
    gap: 4px;
}

.topic-active-indicator {
    font-size: 12.5px;
    color: #00f0ff;
    opacity: 0;
    transition: opacity 0.15s ease, transform 0.15s ease;
    flex-shrink: 0;
}

.codex-topic-card.active .topic-active-indicator {
    opacity: 1;
    transform: translateX(1px);
}

/* Empty Search Results */
.codex-no-results-box {
    padding: 30px 16px;
    text-align: center;
    color: #bfa0cc;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 12px;
}

.no-results-icon {
    font-size: 26px;
}

.codex-clear-filter-btn {
    background: rgba(85, 18, 115, 0.85);
    border: 1.5px solid #ba68c8;
    color: #ffffff;
    padding: 6px 14px;
    border-radius: 4px;
    cursor: pointer;
    font-family: 'Inter', sans-serif;
    font-size: 12px;
    font-weight: 600;
    transition: all 0.15s ease;
}

.codex-clear-filter-btn:hover {
    background: #9d4dcc;
    box-shadow: 0 0 10px rgba(212, 0, 255, 0.5);
}

.codex-empty-placeholder {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    height: 100%;
    text-align: center;
    color: #b79cc7;
    padding: 40px;
}

.placeholder-icon {
    font-size: 42px;
    margin-bottom: 12px;
}

.placeholder-title {
    font-family: 'Press Start 2P', monospace;
    font-size: 13px;
    color: #d400ff;
    margin: 0 0 8px 0;
}

.placeholder-desc {
    font-size: 12.5px;
    color: #bfa0cc;
    margin: 0;
}

/* =========================================================
   6. RIGHT CONTENT PANE: LESSON DETAIL VIEWER
   ========================================================= */
.codex-content-area {
    flex: 1 1 0;
    min-width: 0;
    min-height: 0;
    height: 100%;
    max-height: 100%;
    background: var(--theme-card-bg, rgba(18, 9, 34, 0.92));
    backdrop-filter: blur(12px);
    border: 1px solid var(--theme-border, rgba(168, 85, 247, 0.4));
    border-radius: 10px;
    box-shadow: 0 6px 24px rgba(0, 0, 0, 0.6), 0 0 15px var(--theme-glow-soft, rgba(168, 85, 247, 0.12));
    padding: clamp(16px, 2vw, 24px) clamp(18px, 2.5vw, 30px);
    overflow-y: auto;
    overscroll-behavior: contain;
    -webkit-overflow-scrolling: touch;
    scrollbar-width: thin;
    scrollbar-color: var(--theme-scrollbar, #6d28d9) rgba(6, 0, 12, 0.8);
    box-sizing: border-box;
}

/* Topic Hero Banner */
.lesson-hero-banner {
    display: flex;
    align-items: center;
    gap: 18px;
    padding: 16px 20px;
    background: var(--theme-card-bg-subtle, linear-gradient(135deg, rgba(32, 20, 52, 0.95), rgba(16, 10, 30, 0.98)));
    border: 1px solid var(--theme-border, rgba(168, 85, 247, 0.5));
    border-radius: 10px;
    margin-bottom: 16px;
    box-shadow: 0 4px 18px rgba(0, 0, 0, 0.5);
}

.hero-sprite-frame {
    width: 72px;
    height: 72px;
    flex-shrink: 0;
    background: radial-gradient(circle, var(--theme-glow-soft, rgba(124, 58, 237, 0.35)) 0%, rgba(16, 10, 30, 0.95) 75%);
    border: 1.5px solid var(--theme-primary, #a855f7);
    border-radius: 8px;
    padding: 4px;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 0 16px var(--theme-glow, rgba(124, 58, 237, 0.45));
}

.hero-sprite-frame img {
    max-width: 100%;
    max-height: 100%;
    object-fit: contain;
    image-rendering: pixelated;
}

.lesson-hero-details {
    flex: 1;
    min-width: 0;
}

.lesson-hero-tags {
    display: flex;
    align-items: center;
    gap: 6px;
    margin-bottom: 6px;
    flex-wrap: wrap;
}

.lesson-badge {
    padding: 3px 7px;
    border-radius: 4px;
    font-family: 'Press Start 2P', monospace;
    font-size: 12px;
    letter-spacing: 0.5px;
    text-transform: uppercase;
}

.badge-easy { background: rgba(56, 239, 125, 0.15); border: 1px solid #38ef7d; color: #38ef7d; }
.badge-normal { background: rgba(0, 240, 255, 0.15); border: 1px solid #00f0ff; color: #00f0ff; }
.badge-hard { background: rgba(212, 0, 255, 0.15); border: 1px solid #d400ff; color: #d400ff; }
.badge-hell { background: rgba(255, 51, 102, 0.15); border: 1px solid #ff3366; color: #ff3366; }

.badge-category {
    background: var(--theme-glow-soft, rgba(168, 85, 247, 0.15));
    border: 1px solid var(--theme-primary, #a855f7);
    color: var(--theme-text-title, #e9d5ff);
}

.badge-enemy {
    background: var(--theme-card-bg-subtle, rgba(140, 70, 180, 0.25));
    border: 1px solid var(--theme-border, #8e44ad);
    color: var(--theme-text-sub, #e5b3ff);
}

.lesson-hero-title {
    margin: 0 0 6px 0;
    font-size: clamp(16px, 1.6vw, 22px);
    font-weight: 700;
    color: #ffffff;
    letter-spacing: 0.3px;
    line-height: 1.3;
}

.lesson-hero-summary {
    margin: 0;
    font-size: 14.5px;
    line-height: 1.55;
    color: #cbd5e1;
}

/* In-Lesson Launch Banner for Memory Game */
.codex-memory-launch-banner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 14px;
    padding: 12px 18px;
    margin: 14px 0 20px 0;
    background: var(--theme-card-bg-subtle, linear-gradient(135deg, rgba(38, 12, 60, 0.9), rgba(16, 2, 28, 0.95)));
    border: 1.5px solid var(--theme-primary, #a855f7);
    border-radius: 8px;
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.5);
}

.mem-launch-text {
    display: flex;
    align-items: center;
    gap: 12px;
}

.mem-launch-icon {
    font-size: 26px;
    flex-shrink: 0;
}

.mem-launch-title {
    font-family: 'Press Start 2P', monospace;
    font-size: 13.5px;
    color: #e9d5ff;
}

.mem-launch-sub {
    font-size: 11.5px;
    color: #c4b5fd;
    margin-top: 3px;
}

.codex-launch-game-btn {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 8px 14px;
    font-family: 'Press Start 2P', monospace;
    font-size: 13.5px;
    color: #ffffff;
    background: var(--theme-btn-gradient, linear-gradient(180deg, #7c3aed, #581c87));
    border: 1.5px solid var(--theme-primary, #a855f7);
    border-radius: 6px;
    cursor: pointer;
    box-shadow: 0 0 12px var(--theme-glow, rgba(168, 85, 247, 0.4));
    transition: all 0.2s ease;
    white-space: nowrap;
    flex-shrink: 0;
}

.codex-launch-game-btn:hover {
    background: var(--theme-btn-hover-gradient, linear-gradient(180deg, #9333ea, #6b21a8));
    transform: translateY(-1px);
    box-shadow: 0 0 16px var(--theme-glow-strong, rgba(168, 85, 247, 0.6));
}

/* Section Headings */
.lesson-section-header {
    display: flex;
    align-items: center;
    gap: 10px;
    margin: 22px 0 12px 0;
    border-bottom: 1.5px solid var(--theme-border-subtle, rgba(168, 85, 247, 0.3));
    padding-bottom: 6px;
}

.lesson-section-badge {
    font-family: 'JetBrains Mono', monospace;
    font-size: 11px;
    font-weight: 800;
    color: #00f0ff;
    background: rgba(0, 240, 255, 0.15);
    border: 1px solid #00f0ff;
    padding: 2px 6px;
    border-radius: 4px;
    letter-spacing: 1px;
}

.lesson-section-title {
    margin: 0;
    font-family: 'Inter', system-ui, sans-serif;
    font-size: 14px;
    font-weight: 800;
    letter-spacing: 0.8px;
    color: #ffffff;
    text-transform: uppercase;
}

/* Explanation Prose */
.lesson-prose {
    font-size: 16px;
    line-height: 1.75;
    color: #e2e8f0;
    background: rgba(18, 9, 32, 0.7);
    border: 1px solid #4a1961;
    border-radius: 8px;
    padding: 20px 24px;
}

.lesson-prose h2, .lesson-prose h3 {
    margin: 18px 0 10px 0;
    font-size: 18px;
    color: #ffd700;
    font-weight: 700;
}

.lesson-prose h2:first-child, .lesson-prose h3:first-child {
    margin-top: 0;
}

.lesson-prose p {
    margin: 0 0 12px 0;
}

.lesson-prose p:last-child {
    margin-bottom: 0;
}

.lesson-prose ul, .lesson-prose ol {
    margin: 10px 0 14px 22px;
    padding: 0;
}

.lesson-prose li {
    margin-bottom: 8px;
    line-height: 1.65;
}

.lesson-prose code {
    font-family: 'JetBrains Mono', 'Consolas', monospace;
    font-size: 15px;
    background: rgba(0, 0, 0, 0.65);
    padding: 3px 7px;
    border-radius: 4px;
    color: #00f0ff;
    border: 1px solid rgba(0, 240, 255, 0.25);
}

.lesson-prose strong {
    color: #ffffff;
    font-weight: 700;
}

/* Lesson Code Block Wrap (Syntax Blueprint & Working Code) */
.lesson-code-block-wrap {
    background: #090212;
    border: 1.5px solid #3d1452;
    border-radius: 8px;
    margin: 12px 0 20px 0;
    overflow: hidden;
    box-shadow: inset 0 2px 10px rgba(0, 0, 0, 0.8), 0 4px 16px rgba(0, 0, 0, 0.4);
}

.lesson-code-block-wrap.blueprint-wrap {
    border-color: #00f0ff;
    box-shadow: inset 0 2px 10px rgba(0, 0, 0, 0.8), 0 0 14px rgba(0, 240, 255, 0.15);
}

.code-block-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 8px 16px;
    background: rgba(20, 6, 32, 0.95);
    border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

.code-lang-tag {
    font-family: 'JetBrains Mono', monospace;
    font-size: 11px;
    color: #a78bfa;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.blueprint-wrap .code-lang-tag {
    color: #00f0ff;
}

.codex-copy-code-btn {
    font-family: 'JetBrains Mono', monospace;
    font-size: 11px;
    background: rgba(255, 255, 255, 0.06);
    border: 1px solid rgba(255, 255, 255, 0.15);
    color: #e2e8f0;
    padding: 4px 10px;
    border-radius: 4px;
    cursor: pointer;
    transition: all 0.15s ease;
}

.codex-copy-code-btn:hover {
    background: var(--theme-glow-soft, rgba(168, 85, 247, 0.25));
    border-color: var(--theme-primary, #a855f7);
    color: #ffffff;
}

.codex-copy-code-btn.copied {
    background: rgba(56, 239, 125, 0.25);
    border-color: #38ef7d;
    color: #38ef7d;
}

.lesson-code-pre {
    margin: 0;
    padding: 16px 20px;
    font-family: 'JetBrains Mono', Consolas, monospace;
    font-size: 15.5px;
    line-height: 1.7;
    color: #f1f5f9;
    overflow-x: auto;
    tab-size: 4;
}

/* Key Takeaways Card */
.lesson-takeaways-card {
    background: rgba(20, 6, 34, 0.75);
    border: 1.5px solid #4a1961;
    border-radius: 8px;
    padding: 16px 20px;
    margin: 12px 0 22px 0;
}

.lesson-takeaways-list {
    list-style: none;
    padding: 0;
    margin: 0;
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.lesson-takeaways-list li {
    display: flex;
    align-items: flex-start;
    gap: 10px;
    font-size: 14.5px;
    line-height: 1.55;
    color: #e2e8f0;
}

.takeaway-bullet {
    color: #38ef7d;
    font-weight: bold;
    flex-shrink: 0;
}

/* =========================================================
   7. FULL-SCREEN CODEX MEMORY CARD GAME (NO-SCROLL LAYOUT)
   ========================================================= */

/* When Memory Game Mode is Active: Collapse sidebar and make content area 100% full screen */
#codex-screen.memory-game-mode .codex-sidebar {
    display: none !important;
}

#codex-screen.memory-game-mode .codex-body {
    gap: 0 !important;
}

#codex-screen.memory-game-mode .codex-content-area {
    flex: 1 1 100% !important;
    width: 100% !important;
    max-width: 100% !important;
    height: 100% !important;
    padding: 12px 18px !important;
    overflow: hidden !important; /* Disables outer scrollbar - fills entire viewport height */
    display: flex !important;
    flex-direction: column !important;
    border-color: rgba(168, 85, 247, 0.6) !important;
    box-shadow: 0 0 30px rgba(124, 58, 237, 0.25), inset 0 0 20px rgba(0, 0, 0, 0.8) !important;
}

/* Outer Game Wrapper */
.codex-mem-game-wrap {
    display: flex;
    flex-direction: column;
    height: 100%;
    width: 100%;
    gap: 8px;
    box-sizing: border-box;
    overflow: hidden;
    animation: fadeIn 0.2s ease-out;
}

/* Top Navigation, Heading & Scoreboard Bar */
.codex-mem-topbar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    padding: 8px 16px;
    background: linear-gradient(135deg, rgba(34, 12, 54, 0.95), rgba(16, 3, 26, 0.98));
    border: 1.5px solid #8b3ab0;
    border-radius: 8px;
    flex-shrink: 0;
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.5);
}

.codex-mem-topbar-left {
    display: flex;
    align-items: center;
    gap: 12px;
    flex-wrap: wrap;
}

.codex-mem-back-btn {
    font-family: 'Press Start 2P', monospace;
    font-size: 14px;
    color: #e2e8f0;
    background: rgba(255, 255, 255, 0.08);
    border: 1.5px solid rgba(255, 255, 255, 0.28);
    padding: 7px 14px;
    border-radius: 6px;
    cursor: pointer;
    transition: all 0.16s ease;
    letter-spacing: 0.5px;
    user-select: none;
}

.codex-mem-back-btn:hover {
    background: rgba(168, 85, 247, 0.3);
    border-color: #c084fc;
    color: #ffffff;
    transform: translateY(-1px);
    box-shadow: 0 0 12px rgba(168, 85, 247, 0.4);
}

.codex-mem-diff-pill {
    font-family: 'Press Start 2P', monospace;
    font-size: 12.5px;
    padding: 5px 10px;
    border-radius: 4px;
    letter-spacing: 0.8px;
}

.codex-mem-heading {
    font-family: 'Press Start 2P', monospace;
    font-size: 11.5px;
    color: #f3e8ff;
    letter-spacing: 0.5px;
    text-shadow: 0 1px 6px rgba(0, 0, 0, 0.85);
}

.codex-mem-stats-group {
    display: flex;
    align-items: center;
    gap: 10px;
    flex-shrink: 0;
}

.codex-mem-stat-chip {
    display: flex;
    align-items: center;
    gap: 6px;
    background: rgba(10, 2, 20, 0.92);
    border: 1px solid rgba(168, 85, 247, 0.4);
    border-radius: 6px;
    padding: 5px 12px;
    box-shadow: inset 0 2px 6px rgba(0, 0, 0, 0.7);
}

.codex-mem-stat-chip .chip-lbl {
    font-size: 12.5px;
    font-weight: 700;
    color: #a78bfa;
    letter-spacing: 0.5px;
}

.codex-mem-stat-chip .chip-val {
    font-family: 'JetBrains Mono', monospace;
    font-size: 14px;
    font-weight: 800;
    color: #38bdf8;
    text-shadow: 0 1px 4px rgba(0, 0, 0, 0.8);
}

.codex-mem-reset-btn {
    font-family: 'Press Start 2P', monospace;
    font-size: 13px;
    color: #ffffff;
    background: var(--theme-btn-deck-bg, linear-gradient(135deg, rgba(88, 28, 135, 0.85), rgba(59, 7, 100, 0.95)));
    border: 1.5px solid var(--theme-primary, #a855f7);
    padding: 7px 14px;
    border-radius: 6px;
    cursor: pointer;
    transition: all 0.16s ease;
    user-select: none;
    letter-spacing: 0.5px;
    box-shadow: 0 0 10px var(--theme-glow-soft, rgba(168, 85, 247, 0.3));
}

.codex-mem-reset-btn:hover {
    background: var(--theme-btn-hover-gradient, linear-gradient(135deg, #7c3aed, #581c87));
    border-color: var(--theme-accent, #c084fc);
    transform: translateY(-1px);
    box-shadow: 0 0 16px var(--theme-glow-strong, rgba(168, 85, 247, 0.6));
}

/* Compact One-liner Instruction Banner */
.codex-mem-tip-banner {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 6px 14px;
    background: var(--theme-card-bg-subtle, rgba(26, 12, 42, 0.75));
    border: 1px solid var(--theme-border-subtle, rgba(168, 85, 247, 0.35));
    border-left: 4px solid var(--theme-accent, #ffd700);
    border-radius: 6px;
    font-size: 12.5px;
    line-height: 1.4;
    color: #e2e8f0;
    flex-shrink: 0;
}

.codex-mem-tip-banner .tip-icon {
    font-size: 16px;
    flex-shrink: 0;
}

.codex-mem-tip-banner strong {
    color: #ffd700;
}

/* 4x4 Grid Fitting 100% of Remaining Height Without Scrollbars */
.codex-mem-grid {
    flex: 1 1 0;
    min-height: 0;
    height: 100%;
    width: 100%;
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    grid-template-rows: repeat(4, minmax(0, 1fr));
    gap: 10px;
    box-sizing: border-box;
    perspective: 1200px;
    overflow: hidden;
}

/* Individual 3D Flip Card */
.codex-mem-card {
    width: 100%;
    height: 100%;
    position: relative;
    cursor: pointer;
    user-select: none;
    border-radius: 8px;
    perspective: 1000px;
    box-sizing: border-box;
}

.codex-mem-card-inner {
    position: relative;
    width: 100%;
    height: 100%;
    border-radius: 8px;
    transition: transform 0.38s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    transform-style: preserve-3d;
}

.codex-mem-card.flipped .codex-mem-card-inner {
    transform: rotateY(180deg);
}

/* Card Back: Face Down (Faces user initially at 0 deg) */
.codex-mem-card-back {
    position: absolute;
    inset: 0;
    width: 100%;
    height: 100%;
    backface-visibility: hidden;
    -webkit-backface-visibility: hidden;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 6px;
    background: radial-gradient(circle at 50% 30%, #2f0a46 0%, #140220 85%);
    border: 2px solid #582173;
    border-radius: 8px;
    box-shadow: inset 0 0 16px rgba(0, 0, 0, 0.85), 0 3px 8px rgba(0, 0, 0, 0.45);
    box-sizing: border-box;
    transition: border-color 0.16s ease, box-shadow 0.16s ease, transform 0.16s ease;
}

.codex-mem-card:hover:not(.flipped):not(.matched) .codex-mem-card-back {
    border-color: #00f0ff;
    box-shadow: inset 0 0 18px rgba(0, 0, 0, 0.85), 0 0 18px rgba(0, 240, 255, 0.6);
    transform: translateY(-2px);
}

.codex-mem-rune {
    font-size: 28px;
    filter: drop-shadow(0 0 8px rgba(168, 85, 247, 0.75));
}

.codex-mem-brand {
    font-family: 'Press Start 2P', monospace;
    font-size: 13px;
    color: #c4b5fd;
    letter-spacing: 1.5px;
    text-shadow: 0 1px 4px rgba(0, 0, 0, 0.85);
}

/* Card Front: Face Up (Revealed when flipped, rotated 180deg) */
.codex-mem-card-front {
    position: absolute;
    inset: 0;
    width: 100%;
    height: 100%;
    backface-visibility: hidden;
    -webkit-backface-visibility: hidden;
    transform: rotateY(180deg);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 8px 10px;
    box-sizing: border-box;
    text-align: center;
    border-radius: 8px;
    border: 2px solid var(--theme-primary, #a855f7);
    background: radial-gradient(circle at 50% 20%, var(--theme-card-bg-subtle, #240a36) 0%, var(--theme-card-bg, #0d0117) 90%);
    box-shadow: inset 0 0 12px rgba(0, 0, 0, 0.7), 0 4px 12px rgba(0, 0, 0, 0.5);
    overflow: hidden;
}

.codex-mem-badge {
    position: absolute;
    top: 5px;
    right: 6px;
    font-family: 'JetBrains Mono', monospace;
    font-size: 12px;
    font-weight: 800;
    text-transform: uppercase;
    color: #ffd700;
    background: rgba(255, 215, 0, 0.15);
    border: 1px solid rgba(255, 215, 0, 0.4);
    padding: 1px 5px;
    border-radius: 3px;
    letter-spacing: 0.5px;
}

.codex-mem-badge.concept {
    color: #00f0ff;
    background: rgba(0, 240, 255, 0.15);
    border-color: rgba(0, 240, 255, 0.45);
}

.codex-mem-icon {
    font-size: 22px;
    margin-bottom: 4px;
    flex-shrink: 0;
}

.codex-mem-text {
    font-size: 13.5px;
    line-height: 1.35;
    color: #f1f5f9;
    font-weight: 500;
    box-sizing: border-box;
    word-break: break-word;
    display: -webkit-box;
    -webkit-line-clamp: 4;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

/* Concept Cards Front Styling */
.codex-mem-card.card-concept .codex-mem-card-front {
    border-color: #00f0ff;
    background: radial-gradient(circle at 50% 20%, #0c2b3d 0%, #06121c 90%);
    box-shadow: inset 0 0 14px rgba(0, 240, 255, 0.18), 0 4px 12px rgba(0, 0, 0, 0.6);
}

.codex-mem-card.card-concept .codex-mem-text {
    font-family: 'JetBrains Mono', monospace;
    font-size: 16px;
    font-weight: 700;
    color: #38bdf8;
    text-shadow: 0 1px 6px rgba(0, 0, 0, 0.85);
    letter-spacing: 0.5px;
}

/* Definition Cards Front Styling */
.codex-mem-card.card-def .codex-mem-card-front {
    border-color: #eab308;
    background: radial-gradient(circle at 50% 20%, #2b1f0c 0%, #140d04 90%);
    box-shadow: inset 0 0 14px rgba(234, 179, 8, 0.18), 0 4px 12px rgba(0, 0, 0, 0.6);
}

.codex-mem-card.card-def .codex-mem-text {
    font-family: 'Inter', sans-serif;
    font-size: 13px;
    line-height: 1.35;
    color: #fef08a;
    font-weight: 500;
}

/* Matched State */
.codex-mem-card.matched .codex-mem-card-front {
    border-color: #38ef7d !important;
    background: radial-gradient(circle at 50% 20%, #0d381c 0%, #04140a 90%) !important;
    box-shadow: 0 0 20px rgba(56, 239, 125, 0.6), inset 0 0 14px rgba(56, 239, 125, 0.3) !important;
}

.codex-mem-card.matched .codex-mem-text {
    color: #38ef7d !important;
}

.codex-mem-card.matched .codex-mem-badge {
    color: #38ef7d !important;
    border-color: #38ef7d !important;
    background: rgba(56, 239, 125, 0.25) !important;
}

/* Mismatch Wobble Animation */
@keyframes cardWobble {
    0%, 100% { transform: rotateY(180deg) translateX(0); }
    20%, 60% { transform: rotateY(180deg) translateX(-6px); }
    40%, 80% { transform: rotateY(180deg) translateX(6px); }
}

.codex-mem-card.mismatch .codex-mem-card-inner {
    animation: cardWobble 0.45s ease;
}

.codex-mem-card.mismatch .codex-mem-card-front {
    border-color: #ff3366 !important;
    box-shadow: 0 0 20px rgba(255, 51, 102, 0.65) !important;
}

/* Victory Celebration Modal */
.memory-victory-modal-backdrop {
    position: fixed;
    inset: 0;
    z-index: 9999;
    background: rgba(0, 0, 0, 0.88);
    backdrop-filter: blur(8px);
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
    animation: fadeIn 0.2s ease-out;
}

.memory-victory-card {
    background: radial-gradient(circle at 50% 0%, #290840 0%, #12011c 80%, #08000d 100%);
    border: 2px solid #38ef7d;
    box-shadow: 0 0 50px rgba(56, 239, 125, 0.5), 0 20px 60px rgba(0, 0, 0, 0.95);
    border-radius: 14px;
    padding: 36px 32px;
    text-align: center;
    max-width: 520px;
    width: 100%;
}

.victory-trophy-anim {
    font-size: 56px;
    filter: drop-shadow(0 0 18px rgba(255, 215, 0, 0.85));
    margin-bottom: 12px;
    animation: bounce 1s infinite alternate;
}

.victory-title {
    font-family: 'Press Start 2P', monospace;
    font-size: 16px;
    color: #34d399;
    line-height: 1.5;
    margin: 0 0 12px 0;
    text-shadow: 0 2px 8px rgba(0, 0, 0, 0.85), 0 0 6px rgba(52, 211, 153, 0.35);
}

.victory-sub {
    font-size: 14.5px;
    color: #cbd5e1;
    line-height: 1.55;
    margin: 0 0 24px 0;
}

.victory-stats-row {
    display: flex;
    justify-content: center;
    gap: 16px;
    margin-bottom: 26px;
}

.vic-stat {
    background: rgba(0, 0, 0, 0.6);
    border: 1px solid rgba(255, 255, 255, 0.15);
    border-radius: 8px;
    padding: 8px 16px;
    font-size: 13.5px;
    color: #a78bfa;
}

.vic-stat strong {
    color: #00f0ff;
    font-family: 'JetBrains Mono', monospace;
    font-size: 16px;
}

.victory-actions {
    display: flex;
    justify-content: center;
    gap: 14px;
}

.vic-btn {
    padding: 12px 22px;
    font-family: 'Press Start 2P', monospace;
    font-size: 11px;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.18s ease;
    letter-spacing: 0.5px;
}

.vic-replay {
    background: linear-gradient(180deg, #10b981, #047857);
    border: 1.5px solid #38ef7d;
    color: #ffffff;
    box-shadow: 0 0 16px rgba(56, 239, 125, 0.45);
}

.vic-replay:hover {
    transform: translateY(-2px);
    box-shadow: 0 0 24px rgba(56, 239, 125, 0.7);
}

.vic-lessons {
    background: rgba(255, 255, 255, 0.08);
    border: 1.5px solid rgba(255, 255, 255, 0.25);
    color: #e2e8f0;
}

.vic-lessons:hover {
    background: rgba(255, 255, 255, 0.18);
    transform: translateY(-2px);
}

/* Responsive Overrides */
@media (max-width: 900px) {
    .codex-mem-heading {
        display: none;
    }
    .codex-mem-grid {
        gap: 8px;
    }
}

@media (max-width: 600px) {
    #codex-screen.memory-game-mode .codex-content-area {
        overflow-y: auto !important;
    }
    .codex-mem-grid {
        grid-template-columns: repeat(2, 1fr);
        grid-template-rows: repeat(8, 110px);
        gap: 8px;
    }
}

/* =========================================================
   8. BOOTSTRAP MODAL ENHANCEMENTS FOR CODEX
   ========================================================= */
.codex-modal-content {
    background: radial-gradient(circle at 50% 0%, var(--theme-card-bg-subtle, #1c0a2a) 0%, var(--theme-card-bg, #0d0117) 70%, var(--theme-body-bg, #06000c) 100%) !important;
    border: 2px solid var(--theme-primary, #7c3aed) !important;
    box-shadow: 0 0 35px var(--theme-glow, rgba(124, 58, 237, 0.45)), 0 20px 40px rgba(0, 0, 0, 0.8) !important;
    color: var(--theme-text-title, #f3e8ff) !important;
    border-radius: 12px !important;
}

.codex-modal-header {
    background: rgba(30, 8, 48, 0.85) !important;
    padding: 14px 20px !important;
}

.codex-modal-body {
    background: rgba(13, 1, 23, 0.6) !important;
    max-height: 70vh !important;
    overflow-y: auto !important;
}

.codex-modal-footer {
    background: rgba(22, 5, 36, 0.95) !important;
    padding: 12px 20px !important;
}

/* =========================================================
   9. RESPONSIVE BREAKPOINTS
   ========================================================= */
@media (max-width: 992px) {
    .codex-header {
        height: auto;
        min-height: 56px;
        flex-wrap: wrap;
        padding: 10px 14px;
        gap: 10px;
    }
    .codex-header-titles {
        order: -1;
        width: 100%;
        margin-bottom: 2px;
    }
    .codex-body {
        flex-direction: column;
    }
    .codex-sidebar {
        width: 100%;
        height: 220px;
        max-height: 220px;
    }
}

@media (max-width: 640px) {
    #codex-screen {
        padding: 8px 10px;
    }
    .codex-header {
        padding: 8px;
    }
    .codex-back-btn span:last-child {
        display: none;
    }
    .codex-search-box {
        width: 150px;
    }
    .codex-tabs-bar {
        gap: 6px;
        height: 38px;
    }
    .codex-tab {
    font-size: 13.5px;
        padding: 0 4px;
    }
    .codex-tab .tab-sub {
        display: none;
    }
}