/* Reset and Base Styles */
* {
    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: #333;
    background-color: #fff;
}

.de_iv_adv {
    width: 100%;
    height: auto;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    padding: 5px 0;
    /* background-color: #F8F8F8; */
    margin: 100px 0 0px;
}


/* 底部广告位 */

.postionFixed {
    width: 100%;
    min-height: 60px;
    position: fixed;
    display: flex;
    justify-content: center;
    align-items: center;
    background-color: #F8F8F8;
    right: 0;
    left: 0;
    bottom: 0;
    z-index: 9999;
}

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

/* Header and Navigation */
.header {
    background-color: #fff;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

.nav-brand .brand-link {
    font-size: 1.5rem;
    font-weight: 700;
    color: #2563eb;
    text-decoration: none;
}

.nav-menu {
    display: flex;
    list-style: none;
    margin: 0;
    padding: 0;
}

.nav-item {
    position: relative;
    margin-left: 2rem;
}

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

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

/* Dropdown */
.dropdown-menu {
    position: absolute;
    top: 100%;
    left: 0;
    background-color: #fff;
    min-width: 200px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
    border-radius: 8px;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: all 0.3s ease;
    list-style: none;
    padding: 0.5rem 0;
    z-index: 1001;
}

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

.dropdown-link {
    display: block;
    padding: 0.5rem 1rem;
    color: #4b5563;
    text-decoration: none;
    transition: background-color 0.3s ease;
}

.dropdown-link:hover {
    background-color: #f3f4f6;
    color: #2563eb;
}

/* Mobile Menu */
.nav-toggle {
    display: none;
    flex-direction: column;
    cursor: pointer;
    padding: 0.5rem;
}

.bar {
    width: 25px;
    height: 3px;
    background-color: #4b5563;
    margin: 3px 0;
    transition: 0.3s;
}

/* Main Content */
.main {
    margin-top: 70px;
}

/* Hero Section */
.hero {
    padding: 4rem 0;
    background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
    color: #1f2937;
}

.hero-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 3rem;
    align-items: center;
}

.hero-title {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: 1rem;
    line-height: 1.2;
}

.hero-subtitle {
    font-size: 1.25rem;
    margin-bottom: 2rem;
    color: #4b5563;
}

.hero-buttons {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
}

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

.hero-icon {
    font-size: 8rem;
    line-height: 1;
    animation: float 3s ease-in-out infinite;
}

@keyframes float {

    0%,
    100% {
        transform: translateY(0);
    }

    50% {
        transform: translateY(-20px);
    }
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    border-radius: 8px;
    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-color: #2563eb;
    color: white;
    border-color: #2563eb;
}

.btn-primary:hover {
    background-color: #1d4ed8;
    border-color: #1d4ed8;
    transform: translateY(-2px);
}

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

.btn-secondary:hover {
    background-color: #2563eb;
    color: white;
}

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

.btn-outline:hover {
    background-color: #2563eb;
    color: white;
    transform: translateY(-2px);
}

/* Sections */
.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    text-align: center;
    margin-bottom: 1rem;
    color: #1f2937;
}

.section-subtitle {
    font-size: 1.125rem;
    text-align: center;
    color: #6b7280;
    margin-bottom: 3rem;
}

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

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-top: 3rem;
}

.feature-card {
    background-color: white;
    padding: 2rem;
    border-radius: 12px;
    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 {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.feature-title {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: #1f2937;
}

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

/* Test Levels Section */
.test-levels {
    padding: 5rem 0;
}

.levels-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-top: 3rem;
}

.level-card {
    background-color: white;
    border: 2px solid #e5e7eb;
    border-radius: 12px;
    padding: 2rem;
    transition: all 0.3s ease;
    position: relative;
}

.level-card:hover {
    border-color: #2563eb;
    transform: translateY(-5px);
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.1);
}

.level-card.featured {
    border-color: #2563eb;
    background: linear-gradient(135deg, #f0f9ff 0%, #e0f2fe 100%);
    box-shadow: 0 4px 12px rgba(37, 99, 235, 0.15);
}

.level-badge {
    position: absolute;
    top: -10px;
    left: 50%;
    transform: translateX(-50%);
    background-color: #2563eb;
    color: white;
    padding: 0.25rem 1rem;
    border-radius: 20px;
    font-size: 0.875rem;
    font-weight: 600;
}

.level-header {
    text-align: center;
    margin-bottom: 1.5rem;
}

.level-title {
    font-size: 1.5rem;
    font-weight: 700;
    color: #1f2937;
    margin-bottom: 0.5rem;
}

.level-questions {
    background-color: #f3f4f6;
    color: #6b7280;
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    font-size: 0.875rem;
    font-weight: 600;
}

.level-description {
    color: #4b5563;
    margin-bottom: 1.5rem;
    line-height: 1.6;
}

.level-features {
    list-style: none;
    margin-bottom: 2rem;
}

.level-features li {
    padding: 0.5rem 0;
    color: #6b7280;
    position: relative;
    padding-left: 1.5rem;
}

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

.level-footer {
    text-align: center;
}

/* About Preview Section */
.about-preview {
    padding: 5rem 0;
    background-color: #f9fafb;
}

.about-content {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 3rem;
    align-items: center;
}

.about-description {
    color: #4b5563;
    margin-bottom: 1.5rem;
    line-height: 1.7;
    font-size: 1.1rem;
}

.about-image {
    display: flex;
    justify-content: center;
    align-items: center;
}

.about-icon {
    font-size: 6rem;
    line-height: 1;
    animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse {

    0%,
    100% {
        transform: scale(1);
    }

    50% {
        transform: scale(1.1);
    }
}

/* Blog Preview Section */
.blog-preview {
    padding: 5rem 0;
}

.blog-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-top: 3rem;
}

.blog-card {
    background-color: white;
    border-radius: 12px;
    padding: 2rem;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
    transition: all 0.3s ease;
}

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

.blog-category {
    background-color: #dbeafe;
    color: #2563eb;
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    font-size: 0.875rem;
    font-weight: 600;
    text-transform: uppercase;
}

.blog-title {
    font-size: 1.25rem;
    font-weight: 600;
    margin: 1rem 0;
    color: #1f2937;
    line-height: 1.4;
}

.blog-excerpt {
    color: #6b7280;
    margin-bottom: 1.5rem;
    line-height: 1.6;
}

.blog-link {
    color: #2563eb;
    text-decoration: none;
    font-weight: 600;
    transition: color 0.3s ease;
}

.blog-link:hover {
    color: #1d4ed8;
}

.blog-footer {
    text-align: center;
    margin-top: 3rem;
}

/* Footer */
.footer {
    background-color: #1f2937;
    color: white;
    padding: 3rem 0 1rem;
}

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

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

.footer-title {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    color: #2563eb;
}

.footer-subtitle {
    font-size: 1.125rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: #e5e7eb;
}

.footer-description {
    color: #9ca3af;
    margin-bottom: 1.5rem;
    line-height: 1.6;
}

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

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

.footer-link {
    color: #9ca3af;
    text-decoration: none;
    transition: color 0.3s ease;
}

.footer-link:hover {
    color: #2563eb;
}

.social-links {
    display: flex;
    gap: 1rem;
}

.social-link {
    display: inline-block;
    padding: 0.5rem;
    color: #9ca3af;
    text-decoration: none;
    font-size: 1.25rem;
    transition: color 0.3s ease;
}

.social-link:hover {
    color: #2563eb;
}

.footer-bottom {
    border-top: 1px solid #374151;
    padding-top: 1rem;
    text-align: center;
}

.footer-copyright {
    color: #9ca3af;
    font-size: 0.875rem;
}

/* Quiz Styles */
.quiz-container {
    max-width: 800px;
    margin: 0 auto;
    padding: 2rem 1rem;
}

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

.quiz-progress {
    background-color: #e5e7eb;
    height: 8px;
    border-radius: 4px;
    margin: 2rem 0;
    overflow: hidden;
}

.quiz-progress-bar {
    background-color: #2563eb;
    height: 100%;
    transition: width 0.3s ease;
}

.question-card {
    background-color: white;
    border-radius: 12px;
    padding: 2rem;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
    margin-bottom: 2rem;
}

.question-number {
    color: #6b7280;
    font-size: 0.875rem;
    font-weight: 600;
    margin-bottom: 1rem;
}

.question-text {
    font-size: 1.25rem;
    font-weight: 600;
    color: #1f2937;
    margin-bottom: 2rem;
    line-height: 1.5;
}

.options-list {
    list-style: none;
    margin-bottom: 2rem;
}

.option-item {
    margin-bottom: 1rem;
}

.option-label {
    display: block;
    padding: 1rem;
    border: 2px solid #e5e7eb;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s ease;
    background-color: #f9fafb;
    position: relative;
    overflow: hidden;
}

.option-label::after {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(37, 99, 235, 0.1), transparent);
    transition: left 0.5s;
}

.option-input:checked+.option-label::after {
    left: 100%;
}

.option-label:hover {
    border-color: #2563eb;
    background-color: #eff6ff;
}

.option-input {
    margin-right: 0.75rem;
}

.option-input:checked+.option-label {
    border-color: #2563eb;
    background-color: #dbeafe;
    color: #1e40af;
    transform: scale(1.02);
    box-shadow: 0 2px 8px rgba(37, 99, 235, 0.3);
}

.quiz-navigation {
    display: flex;
    justify-content: space-between;
    gap: 1rem;
}

.quiz-btn {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 8px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
}

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

.quiz-btn-primary:hover {
    background-color: #1d4ed8;
}

.quiz-btn-secondary {
    background-color: #6b7280;
    color: white;
}

.quiz-btn-secondary:hover {
    background-color: #4b5563;
}

.quiz-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.results-container {
    text-align: center;
    padding: 3rem 2rem;
}

.score-display {
    font-size: 3rem;
    font-weight: 700;
    color: #2563eb;
    margin-bottom: 1rem;
}

.rating-display {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 2rem;
    padding: 1rem 2rem;
    border-radius: 8px;
    display: inline-block;
}

.rating-novice {
    background-color: #fee2e2;
    color: #dc2626;
}

.rating-learner {
    background-color: #fef3c7;
    color: #d97706;
}

.rating-expert {
    background-color: #d1fae5;
    color: #059669;
}

.rating-master {
    background-color: #ddd6fe;
    color: #7c3aed;
}

/* Next question indicator */
.next-indicator {
    text-align: center;
    margin-top: 1.5rem;
    padding: 1rem;
    background-color: #f0f9ff;
    border: 2px solid #2563eb;
    border-radius: 8px;
    color: #1e40af;
    font-weight: 600;
    animation: fadeInUp 0.3s ease;
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(10px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Responsive Design */
@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        left: -100%;
        height: 100vh;
        top: 70px;
        flex-direction: column;
        background-color: white;
        width: 100%;
        text-align: center;
        transition: 0.3s;
        box-shadow: 0 10px 27px rgba(0, 0, 0, 0.05);
        padding: 2rem 0;
    }

    .page-title {
        font-size: 2em !important;
    }

    .nav-menu.active {
        left: 0;
    }

    .nav-item {
        margin: 1rem 0;
    }

    .nav-toggle {
        display: flex;
    }

    .hero-container {
        grid-template-columns: 1fr;
        text-align: center;
    }

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

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

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

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

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

    .quiz-navigation {
        flex-direction: column;
    }
}

@media (max-width: 480px) {
    .hero-title {
        font-size: 1.75rem;
    }

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

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

    .btn {
        width: 100%;
        max-width: 300px;
    }
}

/* Page-specific styles */
.page-header {
    background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
    color: #1f2937;
    padding: 6rem 0 4rem;
    text-align: center;
}

.page-title {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: 1rem;
}

.page-subtitle {
    font-size: 1.25rem;
    color: #4b5563;
}

.page-content {
    padding: 4rem 0;
}

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

.content-title {
    font-size: 2rem;
    font-weight: 600;
    color: #1f2937;
    margin-bottom: 1rem;
}

.content-text {
    color: #4b5563;
    line-height: 1.7;
    margin-bottom: 1.5rem;
}

/* Tutorial styles */
.tutorial-step {
    background-color: #f9fafb;
    border-left: 4px solid #2563eb;
    padding: 1.5rem;
    margin-bottom: 2rem;
    border-radius: 0 8px 8px 0;
}

.step-number {
    background-color: #2563eb;
    color: white;
    width: 30px;
    height: 30px;
    border-radius: 50%;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    margin-bottom: 1rem;
}

.step-title {
    font-size: 1.25rem;
    font-weight: 600;
    color: #1f2937;
    margin-bottom: 0.5rem;
}

.step-description {
    color: #4b5563;
    line-height: 1.6;
}

/* Blog styles */
.blog-list {
    display: grid;
    gap: 2rem;
}

.blog-item {
    background-color: white;
    border-radius: 12px;
    padding: 2rem;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
    transition: all 0.3s ease;
}

.blog-item:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 15px rgba(0, 0, 0, 0.1);
}

.blog-meta {
    color: #6b7280;
    font-size: 0.875rem;
    margin-bottom: 1rem;
}

.blog-item-title {
    font-size: 1.5rem;
    font-weight: 600;
    color: #1f2937;
    margin-bottom: 1rem;
}

.blog-item-excerpt {
    color: #4b5563;
    line-height: 1.6;
    margin-bottom: 1.5rem;
}

.blog-read-more {
    color: #2563eb;
    text-decoration: none;
    font-weight: 600;
    transition: color 0.3s ease;
}

.blog-read-more:hover {
    color: #1d4ed8;
}

/* Legal pages styles */
.legal-content {
    max-width: 800px;
    margin: 0 auto;
}

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

.legal-title {
    font-size: 1.5rem;
    font-weight: 600;
    color: #1f2937;
    margin-bottom: 1rem;
}

.legal-text {
    color: #4b5563;
    line-height: 1.7;
    margin-bottom: 1rem;
}

.legal-list {
    color: #4b5563;
    margin-left: 2rem;
    margin-bottom: 1rem;
}

.legal-list li {
    margin-bottom: 0.5rem;
}

/* Contact form styles */
.contact-form {
    max-width: 600px;
    margin: 0 auto;
    background-color: white;
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
}

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

.form-label {
    display: block;
    font-weight: 600;
    color: #374151;
    margin-bottom: 0.5rem;
}

.form-input,
.form-textarea {
    width: 100%;
    padding: 0.75rem;
    border: 2px solid #e5e7eb;
    border-radius: 8px;
    font-size: 1rem;
    transition: border-color 0.3s ease;
}

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

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

.form-submit {
    background-color: #2563eb;
    color: white;
    padding: 0.75rem 2rem;
    border: none;
    border-radius: 8px;
    font-weight: 600;
    cursor: pointer;
    transition: background-color 0.3s ease;
    width: 100%;
}

.form-submit:hover {
    background-color: #1d4ed8;
}