/* ==========================================================================
   ENGLISH GRAMMAR & VOCABULARY MASTER (A1 - C2) - EXPANDED SYSTEM STYLES
   ========================================================================== */

:root {
    /* Color Palette - Light Theme Defaults */
    --bg-main: #f8fafc;
    --bg-card: #ffffff;
    --bg-card-hover: #f1f5f9;
    --bg-input: #f8fafc;
    --border-color: #cbd5e1;
    --border-highlight: #94a3b8;
    
    --text-primary: #0f172a;
    --text-secondary: #334155;
    --text-muted: #64748b;
    
    --primary: #4f46e5;
    --primary-hover: #4338ca;
    --accent: #059669;
    --accent-hover: #047857;
    
    /* Highlight Category Colors */
    --color-tb: #ec4899;  /* To Be - Pink */
    --color-sp: #8b5cf6;  /* Simple Present - Purple */
    --color-pc: #3b82f6;  /* Present Continuous - Blue */
    --color-st: #f97316;  /* Simple Past - Orange */
    --color-pt: #10b981;  /* Past Continuous - Emerald */
    --color-pp: #14b8a6;  /* Present Perfect - Teal */
    --color-kp: #0284c7;  /* Past Perfect - Sky */
    --color-ft: #84cc16;  /* Future Forms - Lime */
    --color-qt: #f59e0b;  /* Quantifiers - Amber */
    --color-cs: #a855f7;  /* Comparatives/Superlatives - Violet */
    --color-mv: #eab308;  /* Modal Verbs - Gold */
    --color-pv: #d946ef;  /* Phrasal Verbs - Fuchsia */
    --color-pr: #06b6d4;  /* Prepositions/Connectors - Cyan */
    --color-ps: #6366f1;  /* Passive Voice - Indigo */

    /* Typography & Sizing Defaults */
    --font-base: 'Plus Jakarta Sans', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-heading: 'Outfit', sans-serif;
    --font-size-body: 19px;
    --line-height-body: 1.7;
    
    --radius-sm: 8px;
    --radius-md: 14px;
    --radius-lg: 20px;
    
    --shadow-card: 0 10px 25px -5px rgba(15, 23, 42, 0.08), 0 8px 10px -6px rgba(15, 23, 42, 0.04);
    --shadow-glow: 0 0 20px rgba(79, 70, 229, 0.15);
    
    --transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}

/* Dark Theme Overrides */
body.theme-dark {
    --bg-main: #0b0f19;
    --bg-card: #151c2c;
    --bg-card-hover: #1e293b;
    --bg-input: #0f172a;
    --border-color: #334155;
    --border-highlight: #475569;
    
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --text-muted: #64748b;
    
    --primary: #6366f1;
    --primary-hover: #4f46e5;
    --accent: #10b981;
    --accent-hover: #059669;
    
    --shadow-card: 0 10px 25px -5px rgba(0, 0, 0, 0.4), 0 8px 10px -6px rgba(0, 0, 0, 0.3);
    --shadow-glow: 0 0 20px rgba(99, 102, 241, 0.25);
}

/* Font Size Scaling Classes */
body.font-size-small { --font-size-body: 16px; }
body.font-size-medium { --font-size-body: 19px; }
body.font-size-large { --font-size-body: 22px; }
body.font-size-xlarge { --font-size-body: 25px; }

/* Base Reset */
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    background-color: var(--bg-main);
    color: var(--text-primary);
    font-family: var(--font-base);
    font-size: var(--font-size-body);
    line-height: var(--line-height-body);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    transition: var(--transition);
    -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-heading);
    font-weight: 700;
    color: var(--text-primary);
    line-height: 1.3;
}

h1 { font-size: 1.7rem; letter-spacing: 0.5px; }
h2 { font-size: 1.45rem; margin-bottom: 0.5rem; }
h3 { font-size: 1.2rem; margin-bottom: 0.5rem; }

p {
    margin-bottom: 1rem;
    color: var(--text-secondary);
}

button, input, select, textarea {
    font-family: inherit;
    font-size: inherit;
}

/* ==========================================================================
   TEACHER LOGIN GATE OVERLAY
   ========================================================================== */

.login-gate-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    background: rgba(11, 15, 25, 0.92);
    backdrop-filter: blur(16px);
    z-index: 2000;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 1.5rem;
    transition: var(--transition);
}

.login-gate-overlay.hidden {
    opacity: 0;
    pointer-events: none;
    display: none;
}

.login-card {
    background: var(--bg-card);
    border: 2px solid var(--primary);
    border-radius: var(--radius-lg);
    padding: 2.5rem 2rem;
    max-width: 440px;
    width: 100%;
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.6), var(--shadow-glow);
    text-align: center;
    position: relative;
    animation: popIn 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

@keyframes popIn {
    from { transform: scale(0.9) translateY(10px); opacity: 0; }
    to { transform: scale(1) translateY(0); opacity: 1; }
}

.login-icon-badge {
    width: 64px;
    height: 64px;
    background: linear-gradient(135deg, #6366f1, #8b5cf6);
    border-radius: 16px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2rem;
    color: #ffffff;
    margin: 0 auto 1.25rem;
    box-shadow: 0 10px 20px rgba(99, 102, 241, 0.4);
}

.login-card h2 {
    font-size: 1.6rem;
    margin-bottom: 0.5rem;
    background: linear-gradient(90deg, #818cf8, #c084fc);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.login-card p {
    font-size: 0.95rem;
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
}

.login-form-group {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.password-input-wrapper {
    position: relative;
}

.input-password {
    width: 100%;
    background: var(--bg-main);
    color: var(--text-primary);
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 14px 16px 14px 44px;
    font-size: 1.1rem;
    outline: none;
    transition: var(--transition);
}

.input-password:focus {
    border-color: var(--primary);
    box-shadow: var(--shadow-glow);
}

.password-icon {
    position: absolute;
    left: 16px;
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-muted);
    font-size: 1.1rem;
}

.login-error-msg {
    color: #f87171;
    font-size: 0.9rem;
    font-weight: 600;
    margin-top: 0.25rem;
    display: none;
}

.login-error-msg.visible {
    display: block;
}

/* ==========================================================================
   APP LAYOUT & SIDEBAR NAVIGATION
   ========================================================================== */

.app-layout {
    display: flex;
    min-height: 100vh;
    width: 100%;
}

/* SIDEBAR PANEL */
.app-sidebar {
    width: 270px;
    background: var(--bg-card);
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    position: fixed;
    top: 0;
    bottom: 0;
    left: 0;
    z-index: 150;
    box-shadow: 2px 0 12px rgba(0,0,0,0.06);
    transition: var(--transition);
    overflow-y: auto;
}

.sidebar-header {
    padding: 1.25rem 1.25rem 1rem;
    border-bottom: 1px solid var(--border-color);
}

.brand {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.brand-icon {
    width: 38px;
    height: 38px;
    background: linear-gradient(135deg, #4f46e5, #8b5cf6);
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
    color: #ffffff;
    box-shadow: 0 4px 12px rgba(79, 70, 229, 0.25);
    flex-shrink: 0;
}

.brand-info {
    display: flex;
    flex-direction: column;
    gap: 2px;
}

.brand-title {
    font-size: 1.05rem;
    font-weight: 800;
    color: var(--text-primary);
    margin: 0;
    line-height: 1.2;
}

.sidebar-section {
    padding: 1rem 1.25rem;
    border-bottom: 1px solid var(--border-color);
}

.sidebar-label {
    font-size: 0.7rem;
    font-weight: 800;
    color: var(--text-muted);
    letter-spacing: 0.5px;
    text-transform: uppercase;
    margin-bottom: 0.6rem;
}

.cefr-level-select {
    width: 100%;
    background: var(--bg-main);
    color: var(--text-primary);
    border: 1.5px solid var(--primary);
    border-radius: var(--radius-sm);
    padding: 8px 12px;
    font-weight: 800;
    font-size: 0.9rem;
    cursor: pointer;
    outline: none;
    transition: var(--transition);
}

.cefr-level-select:focus {
    box-shadow: var(--shadow-glow);
}

/* SIDEBAR VERTICAL NAV */
.sidebar-nav {
    padding: 1rem 0.85rem;
    display: flex;
    flex-direction: column;
    gap: 0.35rem;
    flex: 1;
}

.sidebar-nav .nav-tab {
    width: 100%;
    background: transparent;
    border: 1px solid transparent;
    border-radius: var(--radius-sm);
    color: var(--text-secondary);
    padding: 0.7rem 1rem;
    font-size: 0.92rem;
    font-weight: 600;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 10px;
    transition: var(--transition);
    text-align: left;
}

.sidebar-nav .nav-tab:hover {
    color: var(--text-primary);
    background: var(--bg-main);
}

.sidebar-nav .nav-tab * {
    pointer-events: none;
}

.sidebar-nav .nav-tab.active {
    color: var(--primary);
    background: rgba(79, 70, 229, 0.1);
    border-color: rgba(79, 70, 229, 0.25);
    font-weight: 700;
}

/* SIDEBAR FOOTER UTILITIES */
.sidebar-footer {
    padding: 1rem 1.25rem;
    border-top: 1px solid var(--border-color);
    background: var(--bg-card);
}

.sidebar-actions-grid {
    display: flex;
    gap: 0.5rem;
    margin-top: 0.75rem;
}

.btn-sidebar-utility {
    flex: 1;
    background: var(--bg-main);
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    padding: 8px 10px;
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-weight: 600;
    font-size: 0.82rem;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    transition: var(--transition);
}

.btn-sidebar-utility:hover {
    border-color: var(--primary);
    color: var(--primary);
}

.btn-sidebar-utility.btn-lock:hover {
    border-color: #ef4444;
    color: #ef4444;
}

/* MAIN VIEW CANVAS */
.app-main {
    margin-left: 270px;
    flex: 1;
    display: flex;
    flex-direction: column;
    min-width: 0;
    transition: var(--transition);
}

/* TOPBAR HIGHLIGHTER HEADER */
.app-topbar {
    background: var(--bg-card);
    border-bottom: 1px solid var(--border-color);
    padding: 0.6rem 1.25rem;
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: 0 2px 8px rgba(0,0,0,0.06);
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.btn-sidebar-toggle {
    display: none;
    background: var(--bg-main);
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    padding: 6px 12px;
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-size: 1rem;
}

.topbar-highlighters {
    display: flex;
    align-items: center;
    gap: 0.6rem;
    flex-wrap: wrap;
    flex: 1;
}

.cefr-badge {
    background: rgba(79, 70, 229, 0.15);
    border: 1px solid var(--primary);
    color: var(--primary);
    font-size: 0.72rem;
    font-weight: 800;
    padding: 2px 8px;
    border-radius: 4px;
    display: inline-block;
}

.font-adjuster {
    display: flex;
    align-items: center;
    background: var(--bg-main);
    border: 1px solid var(--border-color);
    padding: 2px 4px;
    border-radius: var(--radius-sm);
    gap: 2px;
}

.btn-font-size {
    background: transparent;
    border: none;
    color: var(--text-secondary);
    padding: 2px 6px;
    border-radius: 3px;
    cursor: pointer;
    font-weight: 700;
    font-size: 0.8rem;
    transition: var(--transition);
}

.btn-font-size.active {
    background: var(--primary);
    color: #ffffff;
}

.panel-title {
    font-size: 0.82rem;
    font-weight: 800;
    color: var(--primary);
    display: flex;
    align-items: center;
    gap: 6px;
    text-transform: uppercase;
    white-space: nowrap;
    flex-shrink: 0;
}

.toggle-buttons-grid {
    display: flex;
    flex-direction: row;
    flex-wrap: wrap;
    gap: 0.4rem 0.5rem;
    align-items: center;
    flex: 1;
}

.hl-toggle {
    background: var(--bg-main);
    border: 1.5px solid var(--border-color);
    color: var(--text-secondary);
    padding: 4px 10px;
    border-radius: 6px;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    gap: 6px;
    font-size: 0.8rem;
    font-weight: 600;
    transition: var(--transition);
    user-select: none;
    line-height: 1.2;
    white-space: nowrap;
}

.hl-toggle .toggle-indicator {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: var(--border-color);
    transition: var(--transition);
}

.hl-toggle .toggle-badge {
    background: var(--border-color);
    color: var(--text-primary);
    padding: 1px 4px;
    border-radius: 3px;
    font-size: 0.65rem;
    font-weight: 800;
}

.hl-toggle:hover, .hl-toggle.active {
    border-color: var(--hl-color);
    color: var(--text-primary);
}

.hl-toggle.active .toggle-indicator {
    background: var(--hl-color);
    box-shadow: 0 0 6px var(--hl-color);
}

.hl-toggle.active .toggle-badge {
    background: var(--hl-color);
    color: #ffffff;
}

.panel-quick-actions {
    margin-left: auto;
    display: flex;
    gap: 4px;
}

.btn-action-sm {
    background: var(--bg-main);
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
    padding: 3px 8px;
    border-radius: 4px;
    font-size: 0.75rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
}

.btn-action-sm:hover {
    background: var(--primary);
    color: #fff;
    border-color: var(--primary);
}

/* ==========================================================================
   CARDS & READERS
   ========================================================================== */

.card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 1.75rem;
    margin-bottom: 1.5rem;
    box-shadow: var(--shadow-card);
    transition: var(--transition);
}

.section-intro-card {
    background: linear-gradient(135deg, rgba(99, 102, 241, 0.12), rgba(139, 92, 246, 0.08));
    border: 1px solid rgba(99, 102, 241, 0.3);
    border-radius: var(--radius-lg);
    padding: 1.5rem 1.75rem;
    margin-bottom: 1.5rem;
}

.story-selector-container {
    margin-top: 1rem;
    display: flex;
    align-items: center;
    gap: 1rem;
    flex-wrap: wrap;
}

.custom-select {
    background: var(--bg-main);
    color: var(--text-primary);
    border: 2px solid var(--primary);
    border-radius: var(--radius-sm);
    padding: 10px 14px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    flex: 1;
    min-width: 280px;
    outline: none;
}

.passage-card {
    border-left: 6px solid var(--primary);
}

.passage-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 1rem;
    margin-bottom: 1.25rem;
    padding-bottom: 1rem;
    border-bottom: 1px solid var(--border-color);
}

.passage-text {
    font-size: 1.15em;
    line-height: 2.1;
    color: var(--text-primary);
    background: var(--bg-main);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 1.5rem;
}

/* ==========================================================================
   DYNAMIC HIGHLIGHT SPAN & SENTENCE STYLES
   ========================================================================== */

.hl-sentence {
    display: inline;
    padding: 2px 4px;
    border-radius: 4px;
    transition: var(--transition);
    position: relative;
    line-height: 2.1;
}

.hl-sentence.to-be.active { background: rgba(236, 72, 153, 0.12); }
.hl-sentence.simple-present.active { background: rgba(139, 92, 246, 0.12); }
.hl-sentence.present-cont.active { background: rgba(59, 130, 246, 0.12); }
.hl-sentence.simple-past.active { background: rgba(249, 115, 22, 0.12); }
.hl-sentence.past-cont.active { background: rgba(16, 185, 129, 0.12); }
.hl-sentence.present-perf.active { background: rgba(20, 184, 166, 0.12); }
.hl-sentence.past-perf.active { background: rgba(2, 132, 199, 0.12); }
.hl-sentence.future-form.active { background: rgba(132, 204, 22, 0.15); }
.hl-sentence.passive-voice.active { background: rgba(99, 102, 241, 0.12); }

.hl-span {
    padding: 3px 8px;
    border-radius: 6px;
    font-weight: 700;
    transition: var(--transition);
    display: inline-block;
    position: relative;
    margin: 0 2px;
    cursor: pointer;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
}

.hl-span:hover {
    transform: translateY(-1px);
    filter: brightness(0.95);
}

/* Light Theme Span Highlight Colors - High Contrast Dark Text */
.hl-span.quantifier.active { background: #fef3c7; border: 1px solid #f59e0b; color: #78350f; }
.hl-span.comparative.active { background: #f3e8ff; border: 1px solid #a855f7; color: #581c87; }
.hl-span.modal-verb.active { background: #fef9c3; border: 1px solid #eab308; color: #713f12; }
.hl-span.phrasal-verb.active { background: #fae8ff; border: 1px solid #d946ef; color: #701a75; }
.hl-span.preposition.active { background: #cffafe; border: 1px solid #06b6d4; color: #164e63; }

/* Dark Theme Span Highlight Colors - High Contrast Light Text */
body.theme-dark .hl-span.quantifier.active { background: rgba(245, 158, 11, 0.35); border: 1px solid #f59e0b; color: #fef08a; }
body.theme-dark .hl-span.comparative.active { background: rgba(168, 85, 247, 0.35); border: 1px solid #a855f7; color: #f3e8ff; }
body.theme-dark .hl-span.modal-verb.active { background: rgba(234, 179, 8, 0.38); border: 1px solid #eab308; color: #fef08a; }
body.theme-dark .hl-span.phrasal-verb.active { background: rgba(217, 70, 239, 0.35); border: 1px solid #d946ef; color: #fae8ff; }
body.theme-dark .hl-span.preposition.active { background: rgba(6, 182, 212, 0.35); border: 1px solid #06b6d4; color: #cffafe; }

/* ==========================================================================
   SEARCHABLE RESOURCE TABLES & GLOSSARIES
   ========================================================================== */

.resource-tabs {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 1.25rem;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 0.5rem;
    flex-wrap: wrap;
}

.res-tab {
    background: var(--bg-main);
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
    padding: 6px 14px;
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-weight: 700;
    font-size: 0.9rem;
    transition: var(--transition);
}

.res-tab.active {
    background: var(--primary);
    color: #ffffff;
    border-color: var(--primary);
}

.resource-search-bar {
    display: flex;
    gap: 0.75rem;
    margin-bottom: 1.25rem;
}

.input-search {
    flex: 1;
    background: var(--bg-main);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    padding: 10px 16px;
    font-size: 0.95rem;
    outline: none;
    transition: var(--transition);
}

.input-search:focus {
    border-color: var(--primary);
    box-shadow: var(--shadow-glow);
}

.table-responsive {
    width: 100%;
    overflow-x: auto;
    border-radius: var(--radius-md);
    border: 1px solid var(--border-color);
}

.data-table {
    width: 100%;
    border-collapse: collapse;
    background: var(--bg-card);
    text-align: left;
    font-size: 0.95rem;
}

.data-table th, .data-table td {
    padding: 12px 16px;
    border-bottom: 1px solid var(--border-color);
}

.data-table th {
    background: var(--bg-main);
    color: var(--text-primary);
    font-weight: 700;
}

.data-table tr:hover {
    background: var(--bg-card-hover);
}

.tag-phonetic {
    font-family: monospace;
    background: rgba(99, 102, 241, 0.15);
    color: #818cf8;
    padding: 2px 6px;
    border-radius: 4px;
    font-size: 0.85rem;
    font-weight: 700;
}

/* ==========================================================================
   AUDIO & MODAL POPUPS
   ========================================================================== */

.btn-item-audio, .btn-sentence-audio {
    background: rgba(99, 102, 241, 0.12);
    border: 1px solid rgba(99, 102, 241, 0.3);
    color: var(--primary);
    cursor: pointer;
    margin-left: 8px;
    padding: 3px 8px;
    border-radius: 5px;
    font-size: 0.82rem;
    transition: var(--transition);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    vertical-align: middle;
}

.btn-item-audio:hover, .btn-sentence-audio:hover {
    background: var(--primary);
    color: #ffffff;
    border-color: var(--primary);
    transform: scale(1.1);
}

.hl-sentence.speaking-active, .speaking-active {
    outline: 2px solid var(--primary);
    background: rgba(99, 102, 241, 0.28) !important;
    animation: glowSpeaking 1.5s infinite alternate;
}

@keyframes glowSpeaking {
    from { box-shadow: 0 0 5px rgba(99, 102, 241, 0.4); }
    to { box-shadow: 0 0 15px rgba(99, 102, 241, 0.8); }
}

.floating-audio-bar {
    position: fixed;
    bottom: 24px;
    right: 24px;
    z-index: 990;
    background: var(--bg-card);
    border: 2px solid var(--primary);
    border-radius: var(--radius-md);
    padding: 0.6rem 1rem;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.35), var(--shadow-glow);
    backdrop-filter: blur(12px);
    transition: var(--transition);
}

.audio-bar-content {
    display: flex;
    align-items: center;
    gap: 1rem;
    flex-wrap: wrap;
}

.btn-audio-btn {
    background: var(--bg-main);
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    padding: 6px 14px;
    border-radius: var(--radius-sm);
    font-size: 0.85rem;
    font-weight: 700;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 6px;
    transition: var(--transition);
}

.btn-audio-btn.btn-play { background: var(--primary); color: #ffffff; }
.btn-audio-btn.btn-stop { background: #ef4444; color: #ffffff; }

.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    background: rgba(11, 15, 25, 0.75);
    backdrop-filter: blur(8px);
    z-index: 1000;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 1rem;
}

.modal-overlay.hidden { display: none; }

.modal-card {
    background: var(--bg-card);
    border: 2px solid var(--primary);
    border-radius: var(--radius-lg);
    padding: 1.75rem;
    max-width: 480px;
    width: 100%;
    box-shadow: 0 20px 40px rgba(0,0,0,0.4), var(--shadow-glow);
    position: relative;
}

.modal-close-btn {
    position: absolute;
    top: 14px;
    right: 14px;
    background: var(--bg-main);
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
    width: 32px;
    height: 32px;
    border-radius: 50%;
    cursor: pointer;
}

/* ==========================================================================
   BUTTONS & EXERCISES
   ========================================================================== */

.btn-primary {
    background: var(--primary);
    color: #ffffff;
    border: none;
    padding: 12px 24px;
    border-radius: var(--radius-sm);
    font-weight: 700;
    font-size: 1.05rem;
    cursor: pointer;
    transition: var(--transition);
}

.btn-primary:hover { background: var(--primary-hover); }

.btn-accent { background: var(--accent); }
.btn-accent:hover { background: var(--accent-hover); }

.q-item, .reader-q-item {
    background: var(--bg-main);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 1.25rem;
    margin-bottom: 1rem;
}

.q-text {
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 0.85rem;
}

.q-options {
    display: flex;
    flex-direction: column;
    gap: 0.6rem;
}

.option-label {
    display: flex;
    align-items: center;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    padding: 10px 14px;
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-size: 0.95em;
}

.option-label:hover { border-color: var(--primary); }

.q-feedback {
    margin-top: 0.85rem;
    padding: 10px 14px;
    border-radius: var(--radius-sm);
    font-size: 0.95rem;
    font-weight: 600;
    display: none;
}

.q-feedback.correct { display: block; background: rgba(16, 185, 129, 0.15); border: 1px solid var(--accent); color: #34d399; }
.q-feedback.incorrect { display: block; background: rgba(239, 68, 68, 0.15); border: 1px solid #ef4444; color: #f87171; }

.hidden { display: none !important; }

/* Sidebar Mobile Backdrop Overlay */
.sidebar-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    background: rgba(15, 23, 42, 0.4);
    backdrop-filter: blur(4px);
    z-index: 140;
    opacity: 0;
    pointer-events: none;
    transition: var(--transition);
}

.sidebar-overlay.active {
    opacity: 1;
    pointer-events: auto;
}

/* Printable PDF Styles */
@media print {
    .app-sidebar, .app-topbar, .sidebar-overlay, .main-header, .control-panel-wrapper, .floating-audio-bar, .modal-overlay, .btn-primary, .btn-secondary, .btn-item-audio, .btn-sentence-audio, .login-gate-overlay, .main-footer {
        display: none !important;
    }
    
    body { background: #ffffff !important; color: #0f172a !important; font-size: 11pt !important; }
    .app-main { margin-left: 0 !important; }
    .main-content { max-width: 100% !important; padding: 0.2in !important; }
    .tab-content#guide-section { display: block !important; }
    .tab-content#reading-section, .tab-content#quiz-section, .tab-content#resources-section { display: none !important; }
    .card, .guide-card, .section-intro-card { background: #ffffff !important; color: #0f172a !important; border: 1.5px solid #cbd5e1 !important; box-shadow: none !important; page-break-inside: avoid; }
    .data-table th, .data-table td { border: 1px solid #cbd5e1 !important; color: #000 !important; background: #fff !important; }
    .data-table th { background: #e2e8f0 !important; }
}

@media (max-width: 1024px) {
    .app-sidebar {
        transform: translateX(-100%);
    }
    .app-sidebar.open {
        transform: translateX(0);
    }
    .app-main {
        margin-left: 0;
    }
    .btn-sidebar-toggle {
        display: flex;
        align-items: center;
        justify-content: center;
    }
}