/**
 * First Principles Tutor - Page-specific CSS
 * Educational tutoring platform with scientific/mathematical theme
 */

/*--------------------------------------------------------------
# Page-specific Variables & Overrides
--------------------------------------------------------------*/
:root {
    --tutor-primary: #1e40af;
    --tutor-secondary: #3730a3;
    --tutor-accent: #059669;
    --tutor-math: #dc2626;
    --tutor-science: #0891b2;
    --tutor-particle: rgba(255, 255, 255, 0.1);
    
    --equation-glow: 0 0 20px rgba(59, 130, 246, 0.5);
    --concept-shadow: 0 8px 32px rgba(0, 0, 0, 0.12);
}

/*--------------------------------------------------------------
# Tutor Hero Section
--------------------------------------------------------------*/
.tutor-hero {
    min-height: calc(100vh - var(--header-height));
    background: linear-gradient(135deg, var(--tutor-primary), var(--tutor-secondary));
    position: relative;
    overflow: hidden;
}

.hero-background {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
}

.hero-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(45deg, rgba(30, 64, 175, 0.1), rgba(55, 48, 163, 0.2));
}

.hero-particles {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-image: 
        radial-gradient(circle at 20% 30%, var(--tutor-particle) 2px, transparent 2px),
        radial-gradient(circle at 80% 70%, var(--tutor-particle) 1px, transparent 1px),
        radial-gradient(circle at 60% 20%, var(--tutor-particle) 1.5px, transparent 1.5px),
        radial-gradient(circle at 30% 80%, var(--tutor-particle) 2px, transparent 2px);
    background-size: 100px 100px, 150px 150px, 200px 200px, 120px 120px;
    animation: floatingParticles 20s ease-in-out infinite;
}

@keyframes floatingParticles {
    0%, 100% { transform: translate(0, 0); }
    25% { transform: translate(-10px, -15px); }
    50% { transform: translate(15px, -10px); }
    75% { transform: translate(-5px, 10px); }
}

.tutor-hero .container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    align-items: center;
    gap: 4rem;
    min-height: calc(100vh - var(--header-height));
    position: relative;
    z-index: 2;
}

.tutor-hero .hero-content {
    color: var(--neutral-white);
}

.hero-title {
    font-size: clamp(2.5rem, 5vw, 4rem);
    font-weight: 800;
    margin-bottom: 1rem;
    background: linear-gradient(45deg, var(--neutral-white), #fbbf24);
    background-clip: text;
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero-subtitle {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 1.5rem;
    color: #fbbf24;
    font-family: var(--font-accent);
}

.hero-description {
    font-size: 1.2rem;
    line-height: 1.7;
    margin-bottom: 2.5rem;
    color: rgba(255, 255, 255, 0.9);
}

.hero-visual {
    display: flex;
    justify-content: center;
    align-items: center;
}

.hero-equation {
    padding: 3rem;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 20px;
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.2);
    box-shadow: var(--equation-glow);
}

.equation-line {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 1rem;
    margin-bottom: 1.5rem;
    font-family: var(--font-header);
    font-size: 1.5rem;
    font-weight: 700;
}

.equation-line.secondary {
    margin-bottom: 0;
    font-size: 1.3rem;
    opacity: 0.8;
}

.variable {
    color: #fbbf24;
    text-shadow: 0 0 10px rgba(251, 191, 36, 0.5);
    animation: pulse 2s ease-in-out infinite;
}

.operator {
    color: var(--neutral-white);
    font-size: 2rem;
}

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.7; }
}

/*--------------------------------------------------------------
# Philosophy Section
--------------------------------------------------------------*/
.philosophy-section {
    padding: 6rem 0;
    background: var(--neutral-light);
}

.philosophy-points {
    margin-top: 3rem;
}

.philosophy-point {
    display: flex;
    align-items: flex-start;
    gap: 1.5rem;
    margin-bottom: 2.5rem;
    padding: 2rem;
    background: var(--neutral-white);
    border-radius: 15px;
    box-shadow: var(--concept-shadow);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.philosophy-point:hover {
    transform: translateY(-5px);
    box-shadow: 0 12px 40px rgba(0, 0, 0, 0.18);
}

.point-icon {
    width: 60px;
    height: 60px;
    background: var(--gradient-accent);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--neutral-white);
    font-size: 1.5rem;
    flex-shrink: 0;
}

.point-content h4 {
    color: var(--tutor-primary);
    margin-bottom: 0.5rem;
    font-size: 1.3rem;
}

.point-content p {
    color: var(--neutral-dark);
    line-height: 1.6;
    margin: 0;
}

/* Concept Visualization */
.concept-visualization {
    position: relative;
    width: 100%;
    height: 400px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.concept-node {
    position: absolute;
    width: 120px;
    height: 120px;
    background: var(--gradient-primary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--neutral-white);
    font-weight: 600;
    font-size: 0.9rem;
    text-align: center;
    box-shadow: var(--shadow-card);
    animation: floatConcept 4s ease-in-out infinite;
}

.concept-node.central {
    position: static;
    width: 150px;
    height: 150px;
    font-size: 1.1rem;
    font-weight: 700;
    background: var(--gradient-accent);
    z-index: 2;
}

.concept-node:nth-child(2) {
    top: 50px;
    left: 50px;
    animation-delay: -1s;
}

.concept-node:nth-child(3) {
    top: 50px;
    right: 50px;
    animation-delay: -2s;
}

.concept-node:nth-child(4) {
    bottom: 50px;
    left: 50px;
    animation-delay: -3s;
}

.concept-node:nth-child(5) {
    bottom: 50px;
    right: 50px;
    animation-delay: -4s;
}

@keyframes floatConcept {
    0%, 100% { transform: translateY(0) scale(1); }
    50% { transform: translateY(-10px) scale(1.05); }
}

/*--------------------------------------------------------------
# Subjects Section
--------------------------------------------------------------*/
.subjects-section {
    padding: 6rem 0;
    background: var(--neutral-white);
}

.subjects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2.5rem;
    margin-bottom: 3rem;
}

.subject-card {
    background: var(--neutral-white);
    border-radius: 20px;
    padding: 2.5rem;
    box-shadow: var(--shadow-card);
    border-top: 5px solid var(--tutor-primary);
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.subject-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 5px;
    background: var(--gradient-primary);
    transition: height 0.3s ease;
}

.subject-card:hover::before {
    height: 100%;
    opacity: 0.05;
}

.subject-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-hover);
}

.subject-icon {
    width: 70px;
    height: 70px;
    background: var(--gradient-primary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--neutral-white);
    font-size: 2rem;
    margin-bottom: 1.5rem;
}

.subject-card h3 {
    color: var(--tutor-primary);
    margin-bottom: 1rem;
    font-size: 1.5rem;
}

.subject-levels {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-bottom: 1.5rem;
}

.level {
    background: var(--neutral-light);
    color: var(--neutral-dark);
    padding: 0.3rem 0.8rem;
    border-radius: 15px;
    font-size: 0.85rem;
    font-weight: 600;
}

.subject-examples {
    background: var(--neutral-light);
    padding: 1.5rem;
    border-radius: 10px;
    margin-top: 1.5rem;
}

.subject-examples strong {
    color: var(--tutor-accent);
}

.subjects-note {
    text-align: center;
    margin-top: 3rem;
}

.note-content {
    display: inline-flex;
    align-items: center;
    gap: 1rem;
    background: var(--gradient-accent);
    color: var(--neutral-white);
    padding: 1.5rem 2rem;
    border-radius: 50px;
    font-size: 1.1rem;
}

.note-content i {
    font-size: 1.5rem;
}

/*--------------------------------------------------------------
# Teaching Method Section
--------------------------------------------------------------*/
.method-section {
    padding: 6rem 0;
    background: var(--neutral-light);
}

.method-steps {
    max-width: 1000px;
    margin: 0 auto;
}

.method-step {
    display: grid;
    grid-template-columns: auto 1fr auto;
    gap: 2rem;
    align-items: center;
    margin-bottom: 4rem;
    position: relative;
}

.method-step::after {
    content: '';
    position: absolute;
    left: 30px;
    top: 80px;
    width: 2px;
    height: calc(100% + 2rem);
    background: var(--gradient-primary);
    z-index: 1;
}

.method-step:last-child::after {
    display: none;
}

.step-number {
    width: 60px;
    height: 60px;
    background: var(--gradient-primary);
    color: var(--neutral-white);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    font-weight: 700;
    z-index: 2;
    position: relative;
}

.step-content {
    background: var(--neutral-white);
    padding: 2.5rem;
    border-radius: 20px;
    box-shadow: var(--shadow-card);
}

.step-content h3 {
    color: var(--tutor-primary);
    margin-bottom: 1rem;
    font-size: 1.4rem;
}

.step-example {
    background: var(--neutral-light);
    padding: 1.5rem;
    border-radius: 10px;
    margin-top: 1.5rem;
    border-left: 4px solid var(--tutor-accent);
    font-style: italic;
}

.step-visual {
    width: 200px;
    height: 150px;
    display: flex;
    align-items: center;
    justify-content: center;
}

/* Visual Diagrams */
.breakdown-diagram {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1rem;
}

.complex-box {
    background: var(--tutor-math);
    color: var(--neutral-white);
    padding: 1rem;
    border-radius: 10px;
    font-weight: 600;
}

.arrow-down {
    width: 0;
    height: 0;
    border-left: 10px solid transparent;
    border-right: 10px solid transparent;
    border-top: 15px solid var(--neutral-gray);
}

.simple-boxes {
    display: flex;
    gap: 0.5rem;
}

.simple-box {
    background: var(--tutor-accent);
    color: var(--neutral-white);
    padding: 0.5rem;
    border-radius: 8px;
    font-size: 0.8rem;
}

.building-diagram {
    display: flex;
    flex-direction: column-reverse;
    align-items: center;
    gap: 0.2rem;
}

.foundation, .layer {
    background: var(--tutor-science);
    color: var(--neutral-white);
    padding: 0.5rem 1rem;
    border-radius: 5px;
    font-size: 0.8rem;
    font-weight: 600;
}

.layer-1 { background: var(--tutor-primary); width: 90%; }
.layer-2 { background: var(--tutor-secondary); width: 80%; }
.layer-3 { background: var(--tutor-accent); width: 70%; }

.connection-diagram {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.theory-bubble, .reality-bubble {
    width: 70px;
    height: 70px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.8rem;
    font-weight: 600;
    text-align: center;
}

.theory-bubble {
    background: var(--tutor-secondary);
    color: var(--neutral-white);
}

.reality-bubble {
    background: var(--tutor-accent);
    color: var(--neutral-white);
}

.connection-line {
    width: 30px;
    height: 2px;
    background: var(--gradient-primary);
}

.practice-diagram {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    position: relative;
}

.practice-level {
    padding: 0.5rem 1rem;
    border-radius: 8px;
    color: var(--neutral-white);
    font-size: 0.8rem;
    font-weight: 600;
    text-align: center;
}

.basic { background: #10b981; }
.intermediate { background: #f59e0b; }
.advanced { background: #dc2626; }

/*--------------------------------------------------------------
# Outcomes Section
--------------------------------------------------------------*/
.outcomes-section {
    padding: 6rem 0;
    background: var(--neutral-white);
}

.outcomes-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-bottom: 4rem;
}

.outcome-metric {
    text-align: center;
    padding: 2.5rem;
    background: var(--neutral-light);
    border-radius: 20px;
    transition: transform 0.3s ease;
}

.outcome-metric:hover {
    transform: translateY(-5px);
}

.metric-icon {
    width: 80px;
    height: 80px;
    background: var(--gradient-primary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--neutral-white);
    font-size: 2rem;
    margin: 0 auto 1.5rem;
}

.metric-value {
    margin-bottom: 1rem;
}

.metric-value .number {
    font-size: 2.5rem;
    font-weight: 800;
    color: var(--tutor-primary);
    display: block;
    line-height: 1;
}

.metric-value .unit {
    font-size: 1.2rem;
    color: var(--tutor-accent);
    font-weight: 600;
}

.student-stories {
    margin-top: 4rem;
}

.student-stories h3 {
    text-align: center;
    color: var(--tutor-primary);
    margin-bottom: 3rem;
    font-size: 2rem;
}

.stories-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.story-card {
    background: var(--neutral-white);
    padding: 2rem;
    border-radius: 20px;
    box-shadow: var(--shadow-card);
    border-top: 4px solid var(--tutor-accent);
}

.story-quote {
    margin-bottom: 1.5rem;
    position: relative;
}

.story-quote i {
    font-size: 2rem;
    color: var(--tutor-accent);
    opacity: 0.3;
    position: absolute;
    top: -10px;
    left: -10px;
}

.story-quote p {
    font-style: italic;
    line-height: 1.7;
    padding-left: 2rem;
    color: var(--neutral-dark);
}

.story-author {
    text-align: right;
}

.story-author strong {
    color: var(--tutor-primary);
    display: block;
    margin-bottom: 0.2rem;
}

.story-author span {
    color: var(--neutral-gray);
    font-size: 0.9rem;
}

/*--------------------------------------------------------------
# Sessions Section
--------------------------------------------------------------*/
.sessions-section {
    padding: 6rem 0;
    background: var(--neutral-light);
}

.sessions-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 2rem;
    margin-bottom: 4rem;
}

.session-option {
    background: var(--neutral-white);
    border-radius: 20px;
    padding: 2.5rem;
    box-shadow: var(--shadow-card);
    transition: all 0.3s ease;
    position: relative;
}

.session-option.featured {
    border: 2px solid var(--tutor-accent);
    transform: scale(1.05);
}

.session-option:hover {
    transform: translateY(-8px) scale(1.02);
    box-shadow: var(--shadow-hover);
}

.session-option.featured:hover {
    transform: translateY(-8px) scale(1.07);
}

.featured-badge {
    position: absolute;
    top: -10px;
    right: 20px;
    background: var(--tutor-accent);
    color: var(--neutral-white);
    padding: 0.5rem 1rem;
    border-radius: 15px;
    font-size: 0.8rem;
    font-weight: 600;
}

.session-icon {
    width: 70px;
    height: 70px;
    background: var(--gradient-primary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--neutral-white);
    font-size: 2rem;
    margin-bottom: 1.5rem;
}

.session-features {
    margin: 2rem 0;
}

.feature {
    display: flex;
    align-items: center;
    gap: 0.8rem;
    margin-bottom: 1rem;
}

.feature i {
    color: var(--tutor-accent);
    font-size: 1.2rem;
}

.session-ideal {
    background: var(--neutral-light);
    padding: 1.5rem;
    border-radius: 10px;
    margin-top: 2rem;
    font-size: 0.95rem;
    line-height: 1.6;
}

.session-ideal strong {
    color: var(--tutor-primary);
}

.delivery-options {
    margin-top: 4rem;
    text-align: center;
}

.delivery-options h3 {
    color: var(--tutor-primary);
    margin-bottom: 2rem;
    font-size: 1.8rem;
}

.delivery-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
}

.delivery-option {
    background: var(--neutral-white);
    padding: 2rem;
    border-radius: 15px;
    box-shadow: var(--shadow-card);
}

.delivery-option i {
    font-size: 3rem;
    color: var(--tutor-primary);
    margin-bottom: 1rem;
}

.delivery-option h4 {
    color: var(--tutor-primary);
    margin-bottom: 1rem;
}

/*--------------------------------------------------------------
# Learning Promise
--------------------------------------------------------------*/
.learning-promise {
    display: flex;
    align-items: flex-start;
    gap: 1.5rem;
    background: var(--gradient-accent);
    color: var(--neutral-white);
    padding: 2rem;
    border-radius: 15px;
    margin-bottom: 2rem;
}

.promise-icon {
    width: 60px;
    height: 60px;
    background: rgba(255, 255, 255, 0.2);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    flex-shrink: 0;
}

.promise-content h4 {
    color: var(--neutral-white);
    margin-bottom: 0.5rem;
}

.promise-content p {
    color: rgba(255, 255, 255, 0.9);
    margin: 0;
}

/*--------------------------------------------------------------
# Responsive Design
--------------------------------------------------------------*/
@media (max-width: 768px) {
    .tutor-hero .container {
        grid-template-columns: 1fr;
        text-align: center;
        gap: 3rem;
    }
    
    .hero-equation {
        padding: 2rem;
    }
    
    .equation-line {
        font-size: 1.2rem;
        flex-wrap: wrap;
    }
    
    .philosophy-point {
        flex-direction: column;
        text-align: center;
        gap: 1rem;
    }
    
    .concept-visualization {
        height: 300px;
    }
    
    .concept-node {
        width: 80px;
        height: 80px;
        font-size: 0.7rem;
    }
    
    .concept-node.central {
        width: 100px;
        height: 100px;
        font-size: 0.9rem;
    }
    
    .method-step {
        grid-template-columns: auto 1fr;
        gap: 1.5rem;
    }
    
    .step-visual {
        grid-column: 1 / -1;
        width: 100%;
        margin-top: 1rem;
    }
    
    .method-step::after {
        left: 29px;
    }
    
    .subjects-grid {
        grid-template-columns: 1fr;
    }
    
    .sessions-grid {
        grid-template-columns: 1fr;
    }
    
    .session-option.featured {
        transform: none;
    }
    
    .session-option.featured:hover {
        transform: translateY(-5px);
    }
    
    .outcomes-grid {
        grid-template-columns: 1fr;
    }
    
    .stories-grid {
        grid-template-columns: 1fr;
    }
    
    .delivery-grid {
        grid-template-columns: 1fr;
    }
    
    .learning-promise {
        flex-direction: column;
        text-align: center;
    }
}

@media (max-width: 1024px) {
    .method-step {
        grid-template-columns: 1fr;
        text-align: center;
        gap: 2rem;
    }
    
    .method-step::after {
        display: none;
    }
    
    .step-number {
        margin: 0 auto 1rem;
    }
    
    .step-visual {
        order: -1;
        margin-bottom: 1rem;
    }

    .pdf-download-card {
        grid-template-columns: 1fr;
        text-align: center;
    }
}

/*--------------------------------------------------------------
# Animation Classes
--------------------------------------------------------------*/
.animate-milestone {
    animation: slideInFromLeft 0.6s ease-out forwards;
}

@keyframes slideInFromLeft {
    from {
        opacity: 0;
        transform: translateX(-50px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

/*--------------------------------------------------------------
# PDF Download Section
--------------------------------------------------------------*/
.pdf-section {
    padding: 4rem 0;
    background: var(--gradient-primary);
}

.pdf-download-card {
    background: rgba(255, 255, 255, 0.95);
    border-radius: 25px;
    padding: 3rem;
    display: flex; /* Use Flexbox */
    justify-content: space-between; /* Pushes items to ends */
    align-items: center; /* Vertically aligns items */
    gap: 2rem;
    box-shadow: var(--shadow-hover);
    backdrop-filter: blur(10px);
    flex-wrap: wrap; /* Allows items to wrap on smaller screens */
}

.pdf-content {
    display: flex;
    gap: 2rem;
    align-items: flex-start;
    flex: 1; /* Allows content to take up available space */
    min-width: 300px; /* Prevents content from getting too squished */
}

.pdf-icon {
    width: 80px;
    height: 80px;
    background: var(--gradient-secondary);
    border-radius: 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--neutral-white);
    font-size: 2.5rem;
    flex-shrink: 0;
}

.pdf-text h3 {
    color: var(--primary-blue);
    margin-bottom: 1rem;
}

.pdf-features {
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
    margin-top: 1rem;
}

.pdf-features span {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    background: var(--neutral-light);
    padding: 0.5rem 1rem;
    border-radius: 20px;
    font-size: 0.9rem;
    font-weight: 500;
}

.pdf-features i {
    color: var(--accent-green);
}

.pdf-action {
    text-align: center;
    flex-shrink: 0; /* Prevents the button area from shrinking */
}

.download-btn {
    background: var(--gradient-secondary);
    color: var(--neutral-white);
    padding: 1.5rem 2rem;
    border-radius: 50px;
    font-weight: 700;
    font-size: 1.1rem;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    box-shadow: var(--shadow-card);
    transition: all 0.3s ease;
    text-decoration: none;
    margin-bottom: 1rem;
}

.download-btn:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-hover);
    color: var(--neutral-white);
}

.pdf-note {
    font-size: 0.9rem;
    color: var(--neutral-gray);
    margin: 0;
}

/* --- Responsive Fix for PDF Card --- */
@media (max-width: 992px) {
    .pdf-download-card {
        flex-direction: column; /* Stack items vertically */
        text-align: center;
        padding: 2rem;
    }
    
    .pdf-content {
        flex-direction: column; /* Stack icon on top of text */
        align-items: center;
        text-align: center;
    }
}

/*--------------------------------------------------------------
# Featured Videos Section
--------------------------------------------------------------*/
/*--------------------------------------------------------------
# Featured Videos Section
--------------------------------------------------------------*/
.videos-section {
    padding: 6rem 0;
    background: var(--neutral-white);
}

.video-player-container {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 2rem;
    margin-top: 2rem;
}

.main-video {
    position: relative;
    border-radius: 20px;
    overflow: hidden;
    box-shadow: var(--shadow-card);
}

.video-loader {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    z-index: 10;
    text-align: center;
    color: var(--tutor-primary);
}

.video-loader.hidden { display: none; }

.loader-spinner {
    width: 40px;
    height: 40px;
    border: 4px solid var(--neutral-light);
    border-top: 4px solid var(--tutor-primary);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin: 0 auto 1rem;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

#main-video-player {
    width: 100%;
    height: 400px;
    border: none;
}

.video-sidebar h3 {
    color: var(--tutor-primary);
    margin-bottom: 1.5rem;
}

.video-thumbnails {
    display: grid;
    gap: 1rem;
}

.video-thumbnail {
    display: flex;
    gap: 1rem;
    padding: 1rem;
    background: var(--neutral-light);
    border-radius: 15px;
    cursor: pointer;
    transition: all 0.3s ease;
    position: relative;
}

.video-thumbnail.active {
    background: linear-gradient(135deg, var(--tutor-primary), var(--tutor-secondary));
    color: var(--neutral-white);
}

.video-thumbnail:hover {
    background: linear-gradient(135deg, var(--tutor-primary), var(--tutor-secondary));
    color: var(--neutral-white);
    transform: translateX(5px);
}

.video-thumbnail img {
    width: 80px;
    height: 60px;
    border-radius: 8px;
    object-fit: cover;
}

.thumbnail-info h4 {
    font-size: 1rem;
    margin-bottom: 0.5rem;
}

.active-indicator {
    position: absolute;
    left: 0;
    top: 50%;
    transform: translateY(-50%);
    width: 4px;
    height: 60%;
    background: var(--secondary-yellow);
    border-radius: 0 4px 4px 0;
    opacity: 0;
    transition: opacity 0.3s ease;
}

.video-thumbnail.active .active-indicator {
    opacity: 1;
}

/* Responsive Rules for Video Section */
@media (max-width: 1024px) {
    .video-player-container {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 768px) {
    #main-video-player {
        height: 250px;
    }
}