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

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    line-height: 1.6;
    color: #1f2937;
    background-color: #ffffff;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
}

/* Header & Navigation */
.header {
    background: #ffffff;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    position: sticky;
    top: 0;
    z-index: 100;
}

.nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem;
    max-width: 1200px;
    margin: 0 auto;
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    text-decoration: none;
    color: #1f2937;
    font-weight: 700;
    font-size: 1.25rem;
}

.nav-menu {
    display: flex;
    gap: 2rem;
    align-items: center;
}

.nav-link {
    text-decoration: none;
    color: #4b5563;
    font-weight: 500;
    transition: color 0.3s ease;
    padding: 0.5rem 0;
}

.nav-link:hover,
.nav-link:focus {
    color: #2563eb;
}

.nav-toggle {
    display: none;
    flex-direction: column;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
}

.nav-toggle span {
    width: 25px;
    height: 3px;
    background: #1f2937;
    margin: 3px 0;
    transition: 0.3s;
    border-radius: 2px;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    border-radius: 0.5rem;
    text-decoration: none;
    font-weight: 600;
    text-align: center;
    transition: all 0.3s ease;
    border: 2px solid transparent;
    cursor: pointer;
    font-size: 1rem;
}

.btn-primary {
    background: #2563eb;
    color: #ffffff;
}

.btn-primary:hover,
.btn-primary:focus {
    background: #1d4ed8;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(37, 99, 235, 0.3);
}

.btn-secondary {
    background: transparent;
    color: #2563eb;
    border-color: #2563eb;
}

.btn-secondary:hover,
.btn-secondary:focus {
    background: #2563eb;
    color: #ffffff;
    transform: translateY(-2px);
}

.btn-success {
    background: #10b981;
    color: #ffffff;
}

.btn-success:hover,
.btn-success:focus {
    background: #059669;
    transform: translateY(-2px);
}

.btn-large {
    padding: 1rem 2rem;
    font-size: 1.125rem;
}

/* Hero Section */
.hero {
    position: relative;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: #ffffff;
    padding: 6rem 0;
    overflow: hidden;
}

.hero-bg {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    opacity: 0.1;
    z-index: 1;
}

.hero-bg-image {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.hero-content {
    position: relative;
    z-index: 2;
    text-align: center;
    max-width: 800px;
    margin: 0 auto;
}

.hero-title {
    font-size: 3rem;
    font-weight: 800;
    margin-bottom: 1.5rem;
    line-height: 1.2;
}

.hero-subtitle {
    font-size: 1.25rem;
    margin-bottom: 2.5rem;
    opacity: 0.9;
    line-height: 1.6;
}

.hero-actions {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
}

/* Features Section */
.features {
    padding: 5rem 0;
    background: #f9fafb;
}

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

.feature-card {
    background: #ffffff;
    padding: 2rem;
    border-radius: 1rem;
    text-align: center;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.feature-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.1);
}

.feature-icon {
    margin-bottom: 1.5rem;
    display: flex;
    justify-content: center;
}

.feature-card h3 {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    color: #1f2937;
}

.feature-card p {
    color: #6b7280;
    line-height: 1.6;
}

/* Course Sections */
.featured-courses,
.courses-catalog {
    padding: 5rem 0;
}

.section-header {
    text-align: center;
    margin-bottom: 3rem;
}

.section-header h2 {
    font-size: 2.5rem;
    font-weight: 800;
    color: #1f2937;
    margin-bottom: 1rem;
}

.section-header p {
    font-size: 1.125rem;
    color: #6b7280;
    max-width: 600px;
    margin: 0 auto;
}

.courses-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 2rem;
    margin-bottom: 3rem;
}

.course-card {
    background: #ffffff;
    border-radius: 1rem;
    overflow: hidden;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    border: 1px solid #e5e7eb;
}

.course-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 20px 25px rgba(0, 0, 0, 0.1);
}

.course-image {
    width: 100%;
    height: 200px;
    object-fit: cover;
    background: #f3f4f6;
}

.course-content {
    padding: 1.5rem;
}

.course-tag {
    display: inline-block;
    background: #dbeafe;
    color: #2563eb;
    padding: 0.25rem 0.75rem;
    border-radius: 1rem;
    font-size: 0.875rem;
    font-weight: 500;
    margin-bottom: 1rem;
}

.course-title {
    font-size: 1.25rem;
    font-weight: 700;
    color: #1f2937;
    margin-bottom: 0.5rem;
    line-height: 1.3;
}

.course-title a {
    text-decoration: none;
    color: inherit;
}

.course-title a:hover {
    color: #2563eb;
}

.course-desc {
    color: #6b7280;
    margin-bottom: 1rem;
    line-height: 1.5;
}

.course-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
    font-size: 0.875rem;
    color: #6b7280;
}

.course-price {
    font-size: 1.5rem;
    font-weight: 700;
    color: #10b981;
    margin-bottom: 1rem;
}

.course-actions {
    display: flex;
    gap: 0.5rem;
}

/* Course Detail Page */
.course-detail {
    padding: 2rem 0;
}

.course-hero {
    background: #f9fafb;
    padding: 3rem 0;
    margin-bottom: 3rem;
}

.course-hero-content {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 3rem;
    align-items: start;
}

.course-hero-info h1 {
    font-size: 2.5rem;
    font-weight: 800;
    color: #1f2937;
    margin-bottom: 1rem;
    line-height: 1.2;
}

.course-hero-info p {
    font-size: 1.125rem;
    color: #6b7280;
    margin-bottom: 2rem;
    line-height: 1.6;
}

.course-hero-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 2rem;
    margin-bottom: 2rem;
}

.meta-item {
    display: flex;
    flex-direction: column;
}

.meta-label {
    font-size: 0.875rem;
    color: #6b7280;
    margin-bottom: 0.25rem;
}

.meta-value {
    font-weight: 600;
    color: #1f2937;
}

.course-sidebar {
    background: #ffffff;
    padding: 2rem;
    border-radius: 1rem;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.1);
    position: sticky;
    top: 2rem;
}

.course-sidebar-image {
    width: 100%;
    height: 200px;
    object-fit: cover;
    border-radius: 0.5rem;
    margin-bottom: 1.5rem;
}

.course-sidebar-price {
    font-size: 2rem;
    font-weight: 800;
    color: #10b981;
    margin-bottom: 1.5rem;
}

.course-tabs {
    margin-bottom: 3rem;
}

.tab-buttons {
    display: flex;
    border-bottom: 2px solid #e5e7eb;
    margin-bottom: 2rem;
    flex-wrap: wrap;
}

.tab-button {
    background: none;
    border: none;
    padding: 1rem 1.5rem;
    cursor: pointer;
    font-weight: 600;
    color: #6b7280;
    border-bottom: 3px solid transparent;
    transition: all 0.3s ease;
}

.tab-button.active {
    color: #2563eb;
    border-bottom-color: #2563eb;
}

.tab-button:hover {
    color: #2563eb;
}

.tab-content {
    display: none;
}

.tab-content.active {
    display: block;
}

.content-section {
    margin-bottom: 3rem;
}

.content-section h3 {
    font-size: 1.5rem;
    font-weight: 700;
    color: #1f2937;
    margin-bottom: 1rem;
}

.content-list {
    list-style: none;
}

.content-list li {
    padding: 0.5rem 0;
    padding-left: 1.5rem;
    position: relative;
    line-height: 1.5;
}

.content-list li::before {
    content: "✓";
    position: absolute;
    left: 0;
    color: #10b981;
    font-weight: bold;
}

.curriculum-list {
    list-style: none;
}

.curriculum-item {
    background: #f9fafb;
    padding: 1rem;
    margin-bottom: 0.5rem;
    border-radius: 0.5rem;
    border-left: 4px solid #2563eb;
}

.curriculum-title {
    font-weight: 600;
    color: #1f2937;
}

.instructor-info {
    background: #f9fafb;
    padding: 2rem;
    border-radius: 1rem;
    margin-bottom: 2rem;
}

.instructor-name {
    font-size: 1.25rem;
    font-weight: 700;
    color: #1f2937;
    margin-bottom: 1rem;
}

.instructor-bio {
    color: #6b7280;
    line-height: 1.6;
}

.faq-item {
    border-bottom: 1px solid #e5e7eb;
    padding: 1rem 0;
}

.faq-question {
    font-weight: 600;
    color: #1f2937;
    margin-bottom: 0.5rem;
}

.faq-answer {
    color: #6b7280;
    line-height: 1.6;
}

/* Course Catalog */
.catalog-controls {
    background: #f9fafb;
    padding: 2rem;
    border-radius: 1rem;
    margin-bottom: 3rem;
}

.controls-row {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
    align-items: center;
}

.search-box,
.filter-select {
    padding: 0.75rem;
    border: 2px solid #e5e7eb;
    border-radius: 0.5rem;
    font-size: 1rem;
    transition: border-color 0.3s ease;
}

.search-box:focus,
.filter-select:focus {
    outline: none;
    border-color: #2563eb;
}

.search-box {
    flex: 1;
    min-width: 200px;
}

.filter-select {
    min-width: 150px;
}

/* Trust Section */
.trust-section {
    background: #f9fafb;
    padding: 4rem 0;
}

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

.trust-item {
    text-align: center;
    padding: 2rem;
    background: #ffffff;
    border-radius: 1rem;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
}

.trust-icon {
    margin-bottom: 1rem;
    display: flex;
    justify-content: center;
}

.trust-item h3 {
    font-size: 1.25rem;
    font-weight: 700;
    color: #1f2937;
    margin-bottom: 0.5rem;
}

.trust-item p {
    color: #6b7280;
}

/* Forms */
.form-group {
    margin-bottom: 1.5rem;
}

.form-label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 600;
    color: #1f2937;
}

.form-input,
.form-textarea,
.form-select {
    width: 100%;
    padding: 0.75rem;
    border: 2px solid #e5e7eb;
    border-radius: 0.5rem;
    font-size: 1rem;
    transition: border-color 0.3s ease;
}

.form-input:focus,
.form-textarea:focus,
.form-select:focus {
    outline: none;
    border-color: #2563eb;
}

.form-textarea {
    min-height: 120px;
    resize: vertical;
}

.form-error {
    color: #dc2626;
    font-size: 0.875rem;
    margin-top: 0.25rem;
}

.form-checkbox {
    display: flex;
    align-items: flex-start;
    gap: 0.5rem;
    margin-bottom: 1.5rem;
}

.form-checkbox input {
    margin-top: 0.25rem;
}

.form-checkbox label {
    font-size: 0.875rem;
    line-height: 1.5;
}

.form-checkbox a {
    color: #2563eb;
    text-decoration: none;
}

.form-checkbox a:hover {
    text-decoration: underline;
}

/* Checkout */
.checkout-container {
    max-width: 800px;
    margin: 0 auto;
    padding: 2rem 0;
}

.checkout-steps {
    display: flex;
    justify-content: center;
    margin-bottom: 3rem;
    padding: 0 1rem;
}

.step {
    display: flex;
    align-items: center;
    color: #6b7280;
}

.step.active {
    color: #2563eb;
}

.step.completed {
    color: #10b981;
}

.step-number {
    width: 2rem;
    height: 2rem;
    border-radius: 50%;
    background: #e5e7eb;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    margin-right: 0.5rem;
}

.step.active .step-number {
    background: #2563eb;
    color: #ffffff;
}

.step.completed .step-number {
    background: #10b981;
    color: #ffffff;
}

.step:not(:last-child)::after {
    content: "";
    width: 3rem;
    height: 2px;
    background: #e5e7eb;
    margin: 0 1rem;
}

.checkout-form {
    background: #ffffff;
    padding: 2rem;
    border-radius: 1rem;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
    margin-bottom: 2rem;
}

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
}

.order-summary {
    background: #f9fafb;
    padding: 2rem;
    border-radius: 1rem;
    margin-bottom: 2rem;
}

.order-summary h3 {
    font-size: 1.5rem;
    font-weight: 700;
    color: #1f2937;
    margin-bottom: 1.5rem;
}

.summary-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 0;
    border-bottom: 1px solid #e5e7eb;
}

.summary-item:last-child {
    border-bottom: none;
    font-weight: 700;
    font-size: 1.125rem;
    color: #1f2937;
}

.payment-icons {
    display: flex;
    gap: 1rem;
    align-items: center;
    margin-bottom: 2rem;
}

.payment-icon {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

/* Success Page */
.success-container {
    max-width: 600px;
    margin: 0 auto;
    padding: 3rem 1rem;
    text-align: center;
}

.success-icon {
    width: 80px;
    height: 80px;
    background: #10b981;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 2rem;
}

.success-container h1 {
    font-size: 2rem;
    font-weight: 800;
    color: #1f2937;
    margin-bottom: 1rem;
}

.success-container p {
    color: #6b7280;
    margin-bottom: 2rem;
    line-height: 1.6;
}

.order-details {
    background: #f9fafb;
    padding: 2rem;
    border-radius: 1rem;
    margin-bottom: 2rem;
    text-align: left;
}

/* Content Pages */
.content-page {
    padding: 3rem 0;
    max-width: 800px;
    margin: 0 auto;
}

.content-page h1 {
    font-size: 2.5rem;
    font-weight: 800;
    color: #1f2937;
    margin-bottom: 2rem;
}

.content-page h2 {
    font-size: 1.75rem;
    font-weight: 700;
    color: #1f2937;
    margin: 2rem 0 1rem;
}

.content-page h3 {
    font-size: 1.25rem;
    font-weight: 600;
    color: #1f2937;
    margin: 1.5rem 0 0.5rem;
}

.content-page p {
    margin-bottom: 1rem;
    line-height: 1.7;
    color: #4b5563;
}

.content-page ul,
.content-page ol {
    margin-bottom: 1rem;
    padding-left: 2rem;
}

.content-page li {
    margin-bottom: 0.5rem;
    line-height: 1.6;
    color: #4b5563;
}

.contact-info {
    background: #f9fafb;
    padding: 2rem;
    border-radius: 1rem;
    margin-bottom: 2rem;
}

.contact-info h3 {
    margin-top: 0;
}

.contact-info p {
    margin-bottom: 0.5rem;
}

.contact-info a {
    color: #2563eb;
    text-decoration: none;
}

.contact-info a:hover {
    text-decoration: underline;
}

/* Footer */
.footer {
    background: #1f2937;
    color: #ffffff;
    padding: 3rem 0 1rem;
    position: relative;
    overflow: hidden;
}

.footer-bg {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    opacity: 0.05;
    z-index: 1;
}

.footer-bg-image {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.footer-content {
    position: relative;
    z-index: 2;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-bottom: 2rem;
}

.footer-section h4 {
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: 1rem;
    color: #ffffff;
}

.footer-logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: 1rem;
}

.footer-section p {
    color: #d1d5db;
    line-height: 1.6;
    margin-bottom: 1rem;
}

.footer-links {
    list-style: none;
}

.footer-links li {
    margin-bottom: 0.5rem;
}

.footer-links a {
    color: #d1d5db;
    text-decoration: none;
    transition: color 0.3s ease;
}

.footer-links a:hover {
    color: #ffffff;
}

.footer-bottom {
    position: relative;
    z-index: 2;
    text-align: center;
    padding-top: 2rem;
    border-top: 1px solid #374151;
    color: #9ca3af;
}

.section-footer {
    text-align: center;
    margin-top: 2rem;
}

/* Responsive Design */
@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        top: 100%;
        left: 0;
        width: 100%;
        background: #ffffff;
        flex-direction: column;
        padding: 2rem;
        box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
        transform: translateY(-100%);
        opacity: 0;
        visibility: hidden;
        transition: all 0.3s ease;
    }

    .nav-menu.active {
        transform: translateY(0);
        opacity: 1;
        visibility: visible;
    }

    .nav-toggle {
        display: flex;
    }

    .hero-title {
        font-size: 2rem;
    }

    .hero-subtitle {
        font-size: 1.125rem;
    }

    .hero-actions {
        flex-direction: column;
        align-items: center;
    }

    .courses-grid {
        grid-template-columns: 1fr;
    }

    .course-hero-content {
        grid-template-columns: 1fr;
        gap: 2rem;
    }

    .course-sidebar {
        position: static;
    }

    .tab-buttons {
        flex-direction: column;
    }

    .tab-button {
        text-align: left;
        padding: 0.75rem;
    }

    .controls-row {
        flex-direction: column;
    }

    .search-box,
    .filter-select {
        width: 100%;
    }

    .form-row {
        grid-template-columns: 1fr;
    }

    .checkout-steps {
        flex-direction: column;
        align-items: center;
        gap: 1rem;
    }

    .step:not(:last-child)::after {
        display: none;
    }

    .footer-content {
        grid-template-columns: 1fr;
        text-align: center;
    }

    .trust-grid {
        grid-template-columns: 1fr;
    }

    .features-grid {
        grid-template-columns: 1fr;
    }

    .payment-icons {
        justify-content: center;
        flex-wrap: wrap;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 0.5rem;
    }

    .hero {
        padding: 3rem 0;
    }

    .hero-title {
        font-size: 1.75rem;
    }

    .section-header h2 {
        font-size: 2rem;
    }

    .course-card {
        margin: 0 0.5rem;
    }

    .checkout-form,
    .order-summary {
        padding: 1rem;
    }

    .btn {
        width: 100%;
        margin-bottom: 0.5rem;
    }

    .course-actions {
        flex-direction: column;
    }
}

/* Focus and Accessibility */
*:focus {
    outline: 2px solid #2563eb;
    outline-offset: 2px;
}

.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

/* Loading and Animation States */
.loading {
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 3rem;
    color: #6b7280;
}

.fade-in {
    animation: fadeIn 0.5s ease-in;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

/* Print Styles */
@media print {
    .header,
    .footer,
    .btn,
    .nav-toggle {
        display: none;
    }

    body {
        font-size: 12pt;
        line-height: 1.4;
    }

    .container {
        max-width: none;
        padding: 0;
    }
}