/* =========================================================
   CIRCLE SIMULATOR - COMPONENT STYLES
   Premium Educational Components
   ========================================================= */

/* === LEARNING CARDS === */
.learning-card {
    background: var(--card);
    backdrop-filter: blur(var(--glass-blur));
    -webkit-backdrop-filter: blur(var(--glass-blur));
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-2xl);
    overflow: hidden;
    transition: all var(--transition-base);
    cursor: pointer;
    position: relative;
}

.learning-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-xl);
    border-color: var(--primary-200);
    background: var(--glass-bg-strong);
}

.learning-card-image {
    height: 160px;
    background: linear-gradient(135deg, var(--primary-50), var(--primary-100));
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    overflow: hidden;
}

.learning-card-image::before {
    content: '';
    position: absolute;
    width: 200%;
    height: 200%;
    top: -50%;
    left: -50%;
    background: radial-gradient(circle, rgba(59, 130, 246, 0.1) 0%, transparent 50%);
    animation: rotate-slow 30s linear infinite;
}

.learning-card-image .icon {
    font-size: 3rem;
    color: var(--primary-500);
    position: relative;
    z-index: 1;
    filter: drop-shadow(0 4px 12px rgba(59, 130, 246, 0.2));
}

.learning-card-body {
    padding: var(--space-5);
}

.learning-card-title {
    font-size: var(--text-lg);
    font-weight: var(--font-semibold);
    font-family: var(--font-display);
    color: var(--neutral-900);
    margin-bottom: var(--space-2);
}

.learning-card-desc {
    font-size: var(--text-sm);
    color: var(--neutral-500);
    margin-bottom: var(--space-4);
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.learning-card-footer {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--space-3) var(--space-5);
    border-top: 1px solid var(--neutral-100);
    font-size: var(--text-xs);
    color: var(--neutral-500);
}

/* === LESSON CARD === */
.lesson-card {
    display: flex;
    align-items: center;
    gap: var(--space-4);
    padding: var(--space-4);
    border-radius: var(--radius-xl);
    background: var(--card);
    backdrop-filter: blur(var(--glass-blur));
    border: 1px solid var(--glass-border);
    transition: all var(--transition-base);
    cursor: pointer;
}

.lesson-card:hover {
    background: var(--glass-bg-strong);
    transform: translateX(4px);
    box-shadow: var(--shadow-glow);
}

.lesson-card.completed {
    border-left: 4px solid var(--success);
}

.lesson-card.active {
    border-left: 4px solid var(--primary-500);
    background: rgba(59, 130, 246, 0.06);
}

.lesson-card-number {
    width: 36px;
    height: 36px;
    border-radius: var(--radius-full);
    background: var(--primary-100);
    color: var(--primary-700);
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: var(--font-bold);
    font-size: var(--text-sm);
    font-family: var(--font-primary);
    flex-shrink: 0;
}

.lesson-card.completed .lesson-card-number {
    background: var(--success-bg);
    color: var(--success);
}

.lesson-card-content {
    flex: 1;
}

.lesson-card-content h4 {
    font-size: var(--text-sm);
    font-weight: var(--font-semibold);
    font-family: var(--font-primary);
    color: var(--neutral-900);
    margin-bottom: var(--space-1);
}

.lesson-card-content p {
    font-size: var(--text-xs);
    color: var(--neutral-500);
}

.lesson-card-status {
    font-size: var(--text-xs);
    color: var(--neutral-400);
}

/* === PRACTICE CARD === */
.practice-card {
    background: var(--card);
    backdrop-filter: blur(var(--glass-blur));
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-2xl);
    padding: var(--space-8);
    box-shadow: var(--glass-shadow);
}

.practice-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: var(--space-6);
    padding-bottom: var(--space-4);
    border-bottom: 1px solid var(--neutral-200);
}

.practice-question-number {
    font-size: var(--text-sm);
    color: var(--neutral-500);
    font-weight: var(--font-medium);
    font-family: var(--font-primary);
}

.practice-timer {
    display: flex;
    align-items: center;
    gap: var(--space-2);
    font-size: var(--text-sm);
    font-weight: var(--font-semibold);
    font-family: var(--font-primary);
    color: var(--neutral-700);
}

.practice-timer.warning {
    color: var(--warning);
}

.practice-question {
    font-size: var(--text-lg);
    font-weight: var(--font-medium);
    color: var(--neutral-900);
    margin-bottom: var(--space-6);
    line-height: 1.6;
}

.practice-options {
    display: grid;
    gap: var(--space-3);
    margin-bottom: var(--space-6);
}

.practice-option {
    display: flex;
    align-items: center;
    gap: var(--space-3);
    padding: var(--space-4);
    border: 2px solid var(--neutral-200);
    border-radius: var(--radius-xl);
    cursor: pointer;
    transition: all var(--transition-fast);
    font-size: var(--text-sm);
    color: var(--neutral-700);
    background: rgba(255, 255, 255, 0.5);
}

.practice-option:hover {
    border-color: var(--primary-300);
    background: var(--primary-50);
    transform: translateX(4px);
    box-shadow: var(--shadow-glow-soft);
}

.practice-option.selected {
    border-color: var(--primary-500);
    background: var(--primary-50);
    color: var(--primary-700);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1);
}

.practice-option.correct {
    border-color: var(--success);
    background: var(--success-bg);
    color: #065F46;
}

.practice-option.wrong {
    border-color: var(--error);
    background: var(--error-bg);
    color: #991B1B;
}

.practice-option-letter {
    width: 28px;
    height: 28px;
    border-radius: var(--radius-full);
    background: var(--neutral-100);
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: var(--font-semibold);
    font-family: var(--font-primary);
    font-size: var(--text-xs);
    flex-shrink: 0;
}

.practice-option.selected .practice-option-letter {
    background: var(--primary-500);
    color: white;
    box-shadow: 0 2px 8px rgba(59, 130, 246, 0.3);
}

.practice-option.correct .practice-option-letter {
    background: var(--success);
    color: white;
}

.practice-option.wrong .practice-option-letter {
    background: var(--error);
    color: white;
}

.practice-hint {
    padding: var(--space-4);
    background: var(--warning-bg);
    border-radius: var(--radius-xl);
    font-size: var(--text-sm);
    color: #92400E;
    margin-bottom: var(--space-4);
    display: none;
    border-left: 4px solid var(--warning);
}

.dark .practice-hint {
    color: #FBBF24;
}

.practice-hint.show {
    display: block;
}

.practice-actions {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--space-3);
}

/* === FEEDBACK DIALOG === */
.feedback-overlay {
    position: fixed;
    inset: 0;
    background: rgba(15, 23, 42, 0.5);
    backdrop-filter: blur(12px);
    display: none;
    align-items: center;
    justify-content: center;
    z-index: 200;
    padding: var(--space-4);
}

.feedback-overlay.show {
    display: flex;
}

.feedback-dialog {
    background: var(--card-solid);
    backdrop-filter: blur(32px);
    border: 1px solid var(--glass-border-strong);
    border-radius: var(--radius-3xl);
    padding: var(--space-8);
    max-width: 400px;
    width: 100%;
    text-align: center;
    box-shadow: var(--shadow-2xl);
    animation: modalSlideIn 0.3s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.dark .feedback-dialog {
    background: rgba(15, 23, 42, 0.95);
    border-color: rgba(255, 255, 255, 0.1);
}

.feedback-icon {
    width: 80px;
    height: 80px;
    margin: 0 auto var(--space-4);
    border-radius: var(--radius-full);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2rem;
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.1);
}

.feedback-icon.success {
    background: var(--success-bg);
    color: var(--success);
    box-shadow: 0 8px 24px rgba(34, 197, 94, 0.2);
}

.feedback-icon.error {
    background: var(--error-bg);
    color: var(--error);
    box-shadow: 0 8px 24px rgba(239, 68, 68, 0.2);
}

.feedback-title {
    font-size: var(--text-2xl);
    font-weight: var(--font-bold);
    font-family: var(--font-display);
    margin-bottom: var(--space-2);
}

.feedback-title.success { color: var(--success); }
.feedback-title.error { color: var(--error); }

.feedback-message {
    font-size: var(--text-sm);
    color: var(--neutral-500);
    margin-bottom: var(--space-6);
}

/* === SIMULATOR PANELS === */
.simulator-layout {
    display: grid;
    grid-template-columns: 200px minmax(0, 1fr) 280px;
    gap: var(--space-5);
    min-height: calc(100vh - 200px);
    align-items: start;
    transition: grid-template-columns var(--transition-base);
}

.simulator-workspace {
    background: rgba(255, 255, 255, 0.4);
    backdrop-filter: blur(var(--glass-blur));
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-2xl);
    padding: var(--space-6);
    position: relative;
    overflow: hidden;
    min-width: 0;
    min-height: 520px;
    display: flex;
    align-items: stretch;
    animation: fadeInUp 0.4s ease;
}

.simulator-workspace .geo-grid {
    position: absolute;
    inset: 0;
    background-image:
        linear-gradient(var(--neutral-200) 1px, transparent 1px),
        linear-gradient(90deg, var(--neutral-200) 1px, transparent 1px);
    background-size: 40px 40px;
    opacity: 0.4;
    pointer-events: none;
}

#simulatorSvg {
    width: 100%;
    height: 100%;
    min-height: 500px;
    flex: 1;
}

.simulator-canvas {
    width: 100%;
    height: 100%;
    min-height: 500px;
    position: relative;
}

.simulator-sidebar {
    display: flex;
    flex-direction: column;
    gap: var(--space-4);
    min-width: 0;
}

.simulator-tools {
    display: flex;
    gap: var(--space-2);
    flex-wrap: wrap;
    padding: var(--space-4);
    background: var(--card);
    backdrop-filter: blur(var(--glass-blur));
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-xl);
}

/* Simulator Tools Panel (Left Column) */
.simulator-tools-panel {
    background: var(--card);
    backdrop-filter: blur(var(--glass-blur));
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-xl);
    padding: var(--space-4);
    animation: fadeInUp 0.4s ease;
    position: sticky;
    top: 96px;
}

.simulator-tools-panel .panel-title {
    font-size: var(--text-xs);
    font-weight: var(--font-semibold);
    font-family: var(--font-primary);
    color: var(--neutral-500);
    text-transform: uppercase;
    letter-spacing: 0.08em;
    margin-bottom: var(--space-3);
    padding-bottom: var(--space-2);
    border-bottom: 1px solid var(--neutral-200);
}

/* Panel Title shared style */
.panel-title {
    font-size: var(--text-xs);
    font-weight: var(--font-semibold);
    font-family: var(--font-primary);
    color: var(--neutral-500);
    text-transform: uppercase;
    letter-spacing: 0.08em;
}

/* =========================================================
   INSTRUCTIONS PANEL (Glass Card)
   ========================================================= */
.instructions-panel {
    background: var(--card);
    backdrop-filter: blur(24px);
    -webkit-backdrop-filter: blur(24px);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-2xl);
    box-shadow: 0 8px 32px rgba(31, 38, 135, 0.06);
    margin-bottom: var(--space-6);
    overflow: hidden;
    animation: fadeInUp 0.4s ease;
    transition: box-shadow var(--transition-base), border-color var(--transition-base);
}

.instructions-panel:hover {
    border-color: var(--primary-200);
    box-shadow: 0 12px 40px rgba(31, 38, 135, 0.1);
}

.instructions-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--space-4) var(--space-6);
    cursor: pointer;
    user-select: none;
}

.instructions-title {
    display: flex;
    align-items: center;
    gap: var(--space-3);
}

.instructions-icon {
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: var(--text-base);
    background: var(--primary-50);
    border-radius: var(--radius-lg);
    flex-shrink: 0;
}

.instructions-title h3 {
    font-size: var(--text-base);
    font-weight: var(--font-semibold);
    font-family: var(--font-primary);
    color: var(--neutral-800);
}

.instructions-toggle {
    width: 28px;
    height: 28px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: var(--radius-md);
    background: transparent;
    color: var(--neutral-400);
    font-size: var(--text-lg);
    line-height: 1;
    transition: all var(--transition-fast);
    cursor: pointer;
    border: none;
}

.instructions-toggle:hover {
    background: var(--neutral-100);
    color: var(--neutral-600);
}

.instructions-body {
    max-height: 500px;
    overflow: hidden;
    transition: max-height var(--transition-slow), opacity var(--transition-base), padding var(--transition-slow);
    padding: 0 var(--space-6) var(--space-5);
}

.instructions-panel.collapsed .instructions-body {
    max-height: 0;
    opacity: 0;
    padding: 0 var(--space-6);
}

.instructions-list {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: var(--space-2) var(--space-6);
    margin: 0;
    padding: 0;
    list-style: none;
    counter-reset: instructions;
}

.instructions-list li {
    counter-increment: instructions;
    position: relative;
    padding-left: 28px;
    font-size: var(--text-sm);
    color: var(--neutral-600);
    line-height: 1.5;
    padding-top: var(--space-1);
    padding-bottom: var(--space-1);
}

.instructions-list li::before {
    content: counter(instructions);
    position: absolute;
    left: 0;
    top: var(--space-1);
    width: 20px;
    height: 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--primary-100);
    color: var(--primary-700);
    border-radius: var(--radius-full);
    font-size: 0.65rem;
    font-weight: var(--font-semibold);
    font-family: var(--font-primary);
}

/* =========================================================
   SIMULATOR ENGINE HEADER (Centered)
   ========================================================= */
.simulator-engine-header {
    text-align: center;
    margin-bottom: var(--space-6);
    animation: fadeInUp 0.4s ease;
}

.engine-title-wrap {
    display: inline-flex;
    align-items: center;
    gap: var(--space-3);
    flex-wrap: wrap;
    justify-content: center;
}

.engine-title {
    font-family: var(--font-display);
    font-size: var(--text-2xl);
    font-weight: var(--font-bold);
    background: var(--gradient-text);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    letter-spacing: 0.02em;
    margin: 0;
    filter: drop-shadow(0 2px 8px rgba(59, 130, 246, 0.12));
}

.engine-badge {
    display: inline-flex;
    align-items: center;
    padding: var(--space-1) var(--space-3);
    background: var(--primary-50);
    border: 1px solid var(--primary-100);
    border-radius: var(--radius-full);
    font-size: var(--text-xs);
    font-weight: var(--font-semibold);
    font-family: var(--font-primary);
    color: var(--primary-600);
    text-transform: uppercase;
    letter-spacing: 0.06em;
    white-space: nowrap;
}

.engine-divider {
    width: 120px;
    height: 3px;
    margin: var(--space-3) auto 0;
    background: var(--gradient-primary);
    border-radius: var(--radius-full);
    opacity: 0.6;
}

.simulator-tool {
    width: 44px;
    height: 44px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: var(--radius-lg);
    font-size: var(--text-lg);
    color: var(--neutral-600);
    transition: all var(--transition-fast);
    background: transparent;
}

.simulator-tool:hover {
    background: var(--neutral-100);
    color: var(--neutral-900);
    transform: translateY(-2px);
}

.simulator-tool.active {
    background: var(--primary-50);
    color: var(--primary-600);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.15);
}

/* === PROPERTIES PANEL === */
.properties-panel {
    background: var(--card);
    backdrop-filter: blur(var(--glass-blur));
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-xl);
    padding: var(--space-5);
}

.properties-panel h4 {
    font-size: var(--text-sm);
    font-weight: var(--font-semibold);
    font-family: var(--font-primary);
    color: var(--neutral-700);
    margin-bottom: var(--space-4);
    padding-bottom: var(--space-3);
    border-bottom: 1px solid var(--neutral-200);
}

.property-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--space-2) 0;
    font-size: var(--text-sm);
}

.property-label {
    color: var(--neutral-500);
}

.property-value {
    font-weight: var(--font-semibold);
    font-family: var(--font-mono);
    color: var(--neutral-800);
}

/* === FORMULA PANEL === */
.formula-panel {
    background: var(--card);
    backdrop-filter: blur(var(--glass-blur));
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-xl);
    padding: var(--space-5);
}

.formula-panel h4 {
    font-size: var(--text-sm);
    font-weight: var(--font-semibold);
    font-family: var(--font-primary);
    color: var(--neutral-700);
    margin-bottom: var(--space-4);
    padding-bottom: var(--space-3);
    border-bottom: 1px solid var(--neutral-200);
}

.formula-item {
    padding: var(--space-2) 0;
    text-align: center;
}

.formula-item .formula {
    font-family: var(--font-mono);
    font-size: var(--text-base);
    color: var(--primary-700);
    font-weight: var(--font-semibold);
}

.formula-item .formula-name {
    font-size: var(--text-xs);
    color: var(--neutral-500);
    margin-top: var(--space-1);
}

/* === PROGRESS DASHBOARD === */
.progress-dashboard {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: var(--space-6);
}

.achievement-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: var(--space-4);
}

.achievement-card {
    display: flex;
    align-items: center;
    gap: var(--space-4);
    padding: var(--space-4);
    background: var(--card);
    backdrop-filter: blur(var(--glass-blur));
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-xl);
    transition: all var(--transition-base);
}

.achievement-card:hover {
    background: var(--glass-bg-strong);
    transform: translateY(-3px);
    box-shadow: var(--shadow-glow);
}

.achievement-card.locked {
    opacity: 0.5;
}

.achievement-icon {
    width: 48px;
    height: 48px;
    border-radius: var(--radius-lg);
    background: var(--primary-50);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: var(--text-2xl);
    flex-shrink: 0;
}

.achievement-card.locked .achievement-icon {
    filter: grayscale(1);
}

.achievement-info h4 {
    font-size: var(--text-sm);
    font-weight: var(--font-semibold);
    font-family: var(--font-primary);
    color: var(--neutral-900);
    margin-bottom: var(--space-1);
}

.achievement-info p {
    font-size: var(--text-xs);
    color: var(--neutral-500);
}

/* === LEADERBOARD === */
.leaderboard-card {
    display: flex;
    align-items: center;
    gap: var(--space-4);
    padding: var(--space-4) var(--space-5);
    border-bottom: 1px solid var(--neutral-100);
    transition: all var(--transition-fast);
}

.leaderboard-card:last-child {
    border-bottom: none;
}

.leaderboard-card:hover {
    background: rgba(59, 130, 246, 0.04);
}

.leaderboard-rank {
    width: 36px;
    height: 36px;
    border-radius: var(--radius-full);
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: var(--font-bold);
    font-size: var(--text-sm);
    font-family: var(--font-primary);
    flex-shrink: 0;
}

.leaderboard-rank.gold {
    background: linear-gradient(135deg, #FBBF24, #F59E0B);
    color: white;
    box-shadow: 0 4px 12px rgba(245, 158, 11, 0.4);
}

.leaderboard-rank.silver {
    background: linear-gradient(135deg, #D1D5DB, #9CA3AF);
    color: white;
    box-shadow: 0 4px 12px rgba(156, 163, 175, 0.4);
}

.leaderboard-rank.bronze {
    background: linear-gradient(135deg, #FB923C, #EA580C);
    color: white;
    box-shadow: 0 4px 12px rgba(234, 88, 12, 0.4);
}

.leaderboard-rank.default {
    background: var(--neutral-100);
    color: var(--neutral-500);
}

.leaderboard-user {
    flex: 1;
    display: flex;
    align-items: center;
    gap: var(--space-3);
}

.leaderboard-user .avatar {
    width: 36px;
    height: 36px;
}

.leaderboard-user-info h4 {
    font-size: var(--text-sm);
    font-weight: var(--font-semibold);
    font-family: var(--font-primary);
    color: var(--neutral-900);
}

.leaderboard-user-info p {
    font-size: var(--text-xs);
    color: var(--neutral-500);
}

.leaderboard-stats {
    text-align: right;
}

.leaderboard-points {
    font-size: var(--text-sm);
    font-weight: var(--font-bold);
    font-family: var(--font-primary);
    color: var(--primary-600);
}

.leaderboard-rank-status {
    font-size: var(--text-xs);
    color: var(--neutral-500);
}

/* === MASTERY BADGE === */
.mastery-badge {
    display: inline-flex;
    align-items: center;
    gap: var(--space-2);
    padding: var(--space-1) var(--space-3);
    border-radius: var(--radius-full);
    font-size: var(--text-xs);
    font-weight: var(--font-semibold);
    font-family: var(--font-primary);
}

.mastery-badge.beginner {
    background: var(--neutral-100);
    color: var(--neutral-600);
}

.mastery-badge.intermediate {
    background: var(--primary-100);
    color: var(--primary-700);
}

.mastery-badge.advanced {
    background: var(--accent-100);
    color: var(--accent-700);
}

.mastery-badge.expert {
    background: linear-gradient(135deg, #FBBF24, #F59E0B);
    color: white;
}

/* === ACCORDION === */
.accordion {
    border-radius: var(--radius-xl);
    overflow: hidden;
}

.accordion-item {
    border-bottom: 1px solid var(--neutral-200);
}

.accordion-item:last-child {
    border-bottom: none;
}

.accordion-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--space-4) var(--space-5);
    cursor: pointer;
    transition: all var(--transition-fast);
    font-size: var(--text-sm);
    font-weight: var(--font-semibold);
    font-family: var(--font-primary);
    color: var(--neutral-800);
}

.accordion-header:hover {
    background: var(--neutral-50);
}

.accordion-header .accordion-icon {
    width: 20px;
    height: 20px;
    transition: transform var(--transition-base);
    color: var(--neutral-400);
}

.accordion-item.open .accordion-icon {
    transform: rotate(180deg);
}

.accordion-body {
    max-height: 0;
    overflow: hidden;
    transition: max-height var(--transition-slow), padding var(--transition-slow);
}

.accordion-item.open .accordion-body {
    max-height: 500px;
    padding: 0 var(--space-5) var(--space-5);
}

.accordion-body p {
    font-size: var(--text-sm);
    color: var(--neutral-600);
    line-height: 1.6;
}

/* === DARK MODE COMPONENT OVERRIDES === */
.dark .learning-card { background: rgba(30, 41, 59, 0.65); border-color: rgba(255, 255, 255, 0.08); }
.dark .learning-card:hover { background: rgba(30, 41, 59, 0.85); }
.dark .learning-card-title { color: #F1F5F9; }
.dark .learning-card-desc { color: #94A3B8; }
.dark .learning-card-footer { border-top-color: rgba(255, 255, 255, 0.08); color: #94A3B8; }
.dark .card-glass h3 { color: #F1F5F9; }
.dark .lesson-card { background: rgba(30, 41, 59, 0.65); border-color: rgba(255, 255, 255, 0.08); }
.dark .lesson-card:hover { background: rgba(30, 41, 59, 0.85); }
.dark .lesson-card-content h4 { color: #F1F5F9; }
.dark .lesson-card-content p { color: #94A3B8; }
.dark .lesson-card-number { background: rgba(59, 130, 246, 0.2); color: #60A5FA; }
.dark .practice-card { background: rgba(30, 41, 59, 0.65); }
.dark .practice-header { border-bottom-color: rgba(255, 255, 255, 0.08); }
.dark .practice-question-number { color: #94A3B8; }
.dark .practice-timer { color: #CBD5E1; }
.dark .property-label { color: #94A3B8; }
.dark .property-value { color: #F1F5F9; }
.dark .formula-panel h4 { color: #F1F5F9; border-bottom-color: rgba(255, 255, 255, 0.08); }
.dark .formula-item .formula { color: #60A5FA; }
.dark .formula-item .formula-name { color: #94A3B8; }
.dark .simulator-tool { color: #94A3B8; }
.dark .simulator-tool:hover { background: rgba(255, 255, 255, 0.08); color: #F1F5F9; }
.dark .simulator-tool.active { background: rgba(59, 130, 246, 0.2); color: #60A5FA; }
.dark .achievement-card { background: rgba(30, 41, 59, 0.65); border-color: rgba(255, 255, 255, 0.08); }
.dark .achievement-card:hover { background: rgba(30, 41, 59, 0.85); }
.dark .achievement-info h4 { color: #F1F5F9; }
.dark .achievement-info p { color: #94A3B8; }
.dark .leaderboard-card { border-bottom-color: rgba(255, 255, 255, 0.08); }
.dark .leaderboard-card:hover { background: rgba(255, 255, 255, 0.04); }
.dark .leaderboard-user-info h4 { color: #F1F5F9; }
.dark .leaderboard-user-info p { color: #94A3B8; }
.dark .leaderboard-points { color: #60A5FA; }
.dark .leaderboard-rank-status { color: #94A3B8; }
.dark .leaderboard-rank.default { background: rgba(255, 255, 255, 0.08); color: #94A3B8; }
.dark .practice-option { background: rgba(15, 23, 42, 0.5); border-color: rgba(255, 255, 255, 0.1); color: #F1F5F9; }
.dark .practice-option:hover { border-color: #60A5FA; background: rgba(59, 130, 246, 0.1); }
.dark .practice-option.selected { border-color: #60A5FA; background: rgba(59, 130, 246, 0.15); color: #60A5FA; }
.dark .practice-option.correct { border-color: #34D399; background: rgba(16, 185, 129, 0.15); color: #34D399; }
.dark .practice-option.wrong { border-color: #F87171; background: rgba(239, 68, 68, 0.15); color: #F87171; }
.dark .practice-question { color: #F1F5F9; }
.dark .feedback-message { color: #94A3B8; }
.dark .simulator-workspace { background: rgba(15, 23, 42, 0.5); }
.dark .properties-panel h4 { color: #F1F5F9; border-bottom-color: rgba(255, 255, 255, 0.08); }
.dark .accordion-item { border-bottom-color: rgba(255, 255, 255, 0.08); }
.dark .accordion-header { color: #F1F5F9; }
.dark .accordion-header:hover { background: rgba(255, 255, 255, 0.05); }
.dark .accordion-header .accordion-icon { color: #94A3B8; }
.dark .accordion-body p { color: #94A3B8; }
.dark .mastery-badge.beginner { background: rgba(255, 255, 255, 0.08); color: #94A3B8; }

/* Dark mode simulator SVG labels */
.dark .radius-label { fill: #CBD5E1; }
.dark .measurement-text { fill: #60A5FA; }
.dark .grid-line { stroke: rgba(255, 255, 255, 0.08); }
.dark .grid-line-major { stroke: rgba(255, 255, 255, 0.15); }
.dark .axis-line { stroke: rgba(255, 255, 255, 0.25); }

/* Dark mode: new simulator panels */
.dark .simulator-tools-panel {
    background: rgba(30, 41, 59, 0.65);
    border-color: rgba(255, 255, 255, 0.08);
}
.dark .simulator-tools-panel .panel-title {
    color: #94A3B8;
    border-bottom-color: rgba(255, 255, 255, 0.08);
}
.dark .panel-title { color: #94A3B8; }
.dark .instructions-panel {
    background: rgba(30, 41, 59, 0.65);
    border-color: rgba(255, 255, 255, 0.08);
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.25);
}
.dark .instructions-panel:hover {
    border-color: rgba(96, 165, 250, 0.3);
    box-shadow: 0 12px 40px rgba(0, 0, 0, 0.35);
}
.dark .instructions-title h3 { color: #F1F5F9; }
.dark .instructions-icon {
    background: rgba(59, 130, 246, 0.2);
}
.dark .instructions-toggle { color: #94A3B8; }
.dark .instructions-toggle:hover {
    background: rgba(255, 255, 255, 0.08);
    color: #F1F5F9;
}
.dark .instructions-list li { color: #CBD5E1; }
.dark .instructions-list li::before {
    background: rgba(59, 130, 246, 0.25);
    color: #60A5FA;
}
.dark .engine-title {
    background: var(--gradient-text-light);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}
.dark .engine-badge {
    background: rgba(59, 130, 246, 0.15);
    border-color: rgba(96, 165, 250, 0.3);
    color: #60A5FA;
}
.dark .simulator-tools {
    background: rgba(30, 41, 59, 0.65);
    border-color: rgba(255, 255, 255, 0.08);
}
.dark .simulator-sidebar .properties-panel {
    background: rgba(30, 41, 59, 0.65);
    border-color: rgba(255, 255, 255, 0.08);
}
.dark .simulator-sidebar .formula-panel {
    background: rgba(30, 41, 59, 0.65);
    border-color: rgba(255, 255, 255, 0.08);
}

/* Toast Notification */
.notification {
    position: fixed;
    top: 80px;
    right: 20px;
    z-index: 9999;
    padding: 16px 24px;
    border-radius: var(--radius-xl);
    background: var(--card-solid);
    backdrop-filter: blur(var(--glass-blur));
    -webkit-backdrop-filter: blur(var(--glass-blur));
    border: 1px solid var(--glass-border);
    box-shadow: var(--shadow-lg);
    color: var(--foreground);
    font-size: var(--text-sm);
    font-weight: var(--font-medium);
    font-family: var(--font-primary);
    animation: slideInRight 0.3s ease;
    pointer-events: none;
}
.notification.success { border-left: 4px solid var(--success); }
.notification.error { border-left: 4px solid var(--error); }
.notification.warning { border-left: 4px solid var(--warning); }
.notification.info { border-left: 4px solid var(--info); }
.dark .notification { box-shadow: 0 4px 20px rgba(0, 0, 0, 0.3); }
.dark .notification.success { border-left-color: #34D399; }
.dark .notification.error { border-left-color: #F87171; }
.dark .notification.warning { border-left-color: #FBBF24; }
.dark .notification.info { border-left-color: #60A5FA; }

/* === RESPONSIVE ADJUSTMENTS === */
@media (max-width: 1200px) {
    .simulator-layout {
        grid-template-columns: 180px minmax(0, 1fr) 260px;
        gap: var(--space-4);
    }
}

@media (max-width: 1024px) {
    /* Tablet: Stack layout - tools on top, canvas center, properties below */
    .simulator-layout {
        grid-template-columns: 1fr;
        gap: var(--space-4);
    }
    
    .simulator-tools-panel {
        position: static;
        order: -1;
    }
    
    .simulator-tools-panel .simulator-tools {
        grid-template-columns: repeat(4, 1fr) !important;
    }
    
    .simulator-workspace {
        min-height: 420px;
    }
    
    #simulatorSvg {
        min-height: 420px;
    }
    
    .progress-dashboard {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 768px) {
    .practice-card {
        padding: var(--space-5);
    }
    
    .practice-question {
        font-size: var(--text-base);
    }
    
    .feedback-dialog {
        padding: var(--space-6);
    }
    
    .simulator-canvas {
        min-height: 350px;
    }
    
    .simulator-workspace {
        min-height: 360px;
    }
    
    #simulatorSvg {
        min-height: 350px;
    }
    
    .instructions-list {
        grid-template-columns: 1fr;
    }
    
    .engine-title {
        font-size: var(--text-xl);
    }
}

@media (max-width: 480px) {
    .simulator-tools-panel .simulator-tools {
        grid-template-columns: repeat(3, 1fr) !important;
    }
    
    .simulator-workspace {
        min-height: 320px;
    }
    
    #simulatorSvg {
        min-height: 310px;
    }
    
    .instructions-header {
        padding: var(--space-3) var(--space-4);
    }
}
/* =========================================================
   FEATURE ILLUSTRATIONS
   Educational PNG illustrations used as feature visuals.
   Preserves transparency, aspect ratio, responsiveness.
   ========================================================= */
.feature-illustration {
    width: auto;
    height: auto;
    max-width: 100%;
    max-height: 150px;
    object-fit: contain;
    display: inline-block;
    vertical-align: middle;
    transition: transform 0.25s ease;
    pointer-events: none;
}

/* Smaller illustration inside dashboard feature cards */
.feature-card-illustration {
    max-height: 120px;
    margin: 0 auto;
}

/* Gentle hover lift on feature cards that contain an illustration */
.feature-card:hover .feature-illustration {
    transform: translateY(-4px) scale(1.03);
}

/* Fallback banner illustration inside learning module cards */
.feature-banner-illustration {
    max-height: 140px;
    max-width: 140px;
}

/* Page header with title + matching feature illustration */
.page-header-featured {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 24px;
    flex-wrap: wrap;
    margin-bottom: var(--space-8);
}
.page-header-featured .page-header {
    flex: 1;
    min-width: 260px;
    margin-bottom: 0;
    animation: none;
}
.page-header-featured .feature-illustration {
    max-height: 150px;
}

/* Dark Mode: subtle soft glow separates artwork from dark surfaces */
.dark .feature-illustration {
    filter: drop-shadow(0 0 14px rgba(96, 165, 250, 0.25));
}

@media (max-width: 600px) {
    .page-header-featured {
        justify-content: center;
        text-align: center;
    }
    .page-header-featured .page-header {
        min-width: 100%;
    }
    .feature-illustration,
    .page-header-featured .feature-illustration {
        max-height: 110px;
    }
    .feature-card-illustration {
        max-height: 100px;
    }
}
/* =========================================================
   CIRCLE RESPONSIVE AUDIT FIX (frontend-only, CSS presentation)
   Simulator: visual responsiveness only.
   No geometry/calculation/JS behavior changed.
   ========================================================= */
.simulator-layout,
.simulator-workspace,
.simulator-sidebar,
.properties-panel,
.formula-panel,
.instructions-panel {
    min-width: 0;
    max-width: 100%;
}
.simulator-tools { max-width: 100%; }
.simulator-tool { min-width: 0; }
.simulator-tool .tool-label {
    overflow-wrap: break-word;
    word-break: break-word;
}

/* Simulator SVG scales with container; existing min-heights below still apply */
#simulatorSvg {
    width: 100%;
    height: auto;
    max-width: 100%;
    display: block;
    touch-action: manipulation;
}

/* Join/form rows that use inline minmax widths: allow full stacking */
@media (max-width: 576px) {
    div[style*="min-width: 250px"],
    div[style*="min-width: 200px"] {
        flex-basis: 100% !important;
        min-width: 0 !important;
    }
    form[style*="display: flex"] .btn,
    form[style*="display:flex"] .btn {
        width: 100%;
    }
    .simulator-engine-header { flex-wrap: wrap; }
    .engine-title { font-size: 1.05rem; }
    .engine-badge { font-size: 0.68rem; }
    .simulator-tool { padding: 7px 4px; }
    .simulator-tool .tool-label { font-size: 0.62rem; }
    .simulator-tool img { width: 26px; height: 26px; }
    .properties-panel, .formula-panel { padding: var(--space-4); }
    .instructions-body { max-width: 100%; }
    .classroom-tabs { overflow-x: auto; }
    .feedback-options { grid-template-columns: 1fr; }
}

/* Very small phones: 2 tools per row keeps labels readable */
@media (max-width: 400px) {
    .simulator-tools-panel .simulator-tools {
        grid-template-columns: repeat(2, 1fr) !important;
    }
}

/* =========================================================
   Inline card grids use minmax(300-340px); on narrow phones
   force single-column stacking (CSS !important safely
   overrides non-important inline grid declarations).
   ========================================================= */
@media (max-width: 576px) {
    div[style*="minmax(340px"],
    div[style*="minmax(320px"],
    div[style*="minmax(300px"],
    div[style*="minmax(280px"],
    div[style*="minmax(240px"] {
        grid-template-columns: 1fr !important;
    }
}