body {  
    margin: 0;
    padding: 0;
    font-family: Arial, sans-serif;
    color: #333;
}

.container {
    max-width: 90%; 
    padding: 0 150px; 
}

@media (min-width: 1024px) {
    .container {
        max-width: 80%; 
    }
}

section {
    padding: 40px 10; 
}

.top-bar {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 10px calc(5% + 1px); 
    box-sizing: border-box;
    background: rgba(255, 255, 255, 0);
    color: #fff;
    z-index: 1000;
    transition: background-color 0.3s ease, color 0.3s ease;
}

.top-bar.scrolled {
    background: rgba(255, 255, 255, 1);
    color: #0066ee;
}

.top-bar .brand {
    font-size: 1.5rem;
    font-weight: bold;
}

.top-bar .cta-button {
    padding: 10px 20px;
    font-size: 1rem;
    color: #fff;
    background: #0066ee;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    transition: background 0.3s, transform 0.2s;
}

.top-bar .cta-button:hover {
    background: #0056d2;
    transform: translateY(-2px);
}

.navbar {
    position: fixed;
    top: 55px; 
    left: 0;
    width: 100%;
    display: flex;
    justify-content: center; 
    align-items: center;
    padding: 15px 0; 
    background: linear-gradient(to right, rgba(173, 216, 230, 0.5), rgba(255, 255, 255, 1)); 
    backdrop-filter: blur(10px);
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    z-index: 999;
    opacity: 0;
    transform: translateY(-100%);
    transition: opacity 0.3s ease, transform 0.3s ease;
}

.navbar.show {
    opacity: 1;
    transform: translateY(0);
}
.navbar button {
    background-color: transparent;
    border: 2px solid #0066ee; 
    font-size: 1rem;
    font-weight: bold;
    color: #0066ee; 
    margin: 0 10px;
    padding: 10px 16px;
    border-radius: 50px; 
    text-align: center;
    transition: background-color 0.3s ease, color 0.3s ease, box-shadow 0.3s ease;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1); 
}

.navbar button:hover {
    background-color: #0066ee; 
    color: #fff; 
}

.navbar button.active {
    background-color: #0066ee; 
    color: #fff;
    border-color: #0066ee;
    box-shadow: 0 4px 12px rgba(0, 102, 238, 0.6); 
}


.hero-section {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 100px 0; 
    background: linear-gradient(180deg, rgba(0, 102, 238, 1), rgba(147, 131, 251, 1));
    color: #fff;
    min-height: 80vh; 
    position: relative;
}

.hero-section .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 1200px; 
    margin: 0 auto; 
    padding: 0 5%; 
    gap: 20px; 
}

.hero-section .content {
    flex: 1; 
}

.hero-section h1 {
    font-size: 3rem;
    font-weight: 800;
    line-height: 1.5;
    margin: 0;
}

.hero-section h1 .highlight {
    font-weight: 900;
    background: white;
    color: #0066ee;
    padding: 6px 12px;
    border-radius: 6px;
    font-style: italic;
    display: inline-block;
}

.hero-section p {
    font-size: 1.2rem;
    margin: 10px 0;
    color: #d8d8d8;
}

.hero-section .cta-button {
    padding: 14px 28px;
    font-size: 1.1rem;
    color: #0066ee;
    background: #fff;
    border: none;
    border-radius: 30px;
    font-weight: bold;
    cursor: pointer;
    transition: background 0.3s ease, transform 0.2s ease;
    align-self: start;
}

.hero-section .cta-button:hover {
    background: #f5f5f5;
    transform: translateY(-2px);
}

.hero-section img {
    flex-shrink: 0; 
    max-width: 40%;
    width: auto;
    margin-left: 20px; 
}

.features-section {
    text-align: center;
    padding: 80px 5%;
    background: #f9f9f9;
}

.features-section h2 {
    font-size: 2.5rem;
    margin-bottom: 40px;
    font-weight: 800;
    color: #333;
}

.features-section .feature {
    display: grid;
    grid-template-columns: 1fr; 
    grid-gap: 20px;
    margin-bottom: 40px;
    align-items: center;
}

.features-section .feature img {
    max-width: 100%;
    border-radius: 15px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
}

.features-section .feature .content {
    text-align: center; 
}

.features-section .feature .content span {
    font-size: 4rem; 
    font-weight: 900; 
    color: #0066ee;
    display: block; 
    margin-bottom: 10px;
}

.features-section .feature h3 {
    font-size: 1.8rem; 
    color: #0066ee;
    margin-bottom: 10px;
    font-weight: bold;
}

.features-section .feature p {
    font-size: 1.2rem; 
    color: #555;
    line-height: 1.6;
}

@media (min-width: 768px) {
    .features-section .feature {
        grid-template-columns: 1fr 1fr; 
    }

    .features-section .feature:nth-child(even) img {
        order: 2; /* 偶数项图片右侧 */
    }

    .features-section .feature .content {
        text-align: center; /* 大屏幕仍保持文字居中 */
    }
}


.review-section {
    background-color: #1c1c1e;
    color: #fff;
    text-align: center;
    padding: 80px 5%;
}

.review-section .stars {
    font-size: 1.5rem;
    color: #FFD700;
    margin-bottom: 20px;
}

.review-section h2 {
    font-size: 2.5rem;
    font-weight: 800;
    margin: 20px 0;
}

.review-section p {
    font-size: 1.2rem;
    margin: 20px 0;
}

.cta-section {
    background: linear-gradient(200deg, #0066EE, #9383FB);
    color: white;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 100px 5%;
    flex-wrap: nowrap; 
}

.cta-section .container {
    display: flex;
    align-items: center; 
    justify-content: space-between;
    max-width: 1200px; 
    margin: 0 auto; 
    width: 100%; 
}

.cta-section .text {
    max-width: 50%; 
    min-width: 300px;
    text-align: left; 
}

.cta-section h2 {
    font-size: 2.5rem;
    font-weight: 800;
    margin-bottom: 16px;
}

.cta-section p {
    font-size: 1.2rem;
    margin-bottom: 24px;
}

.cta-section .cta-button {
    background-color: #FF8C00;
    color: #fff;
    padding: 12px 24px;
    border: none;
    border-radius: 8px;
    font-size: 1.2rem;
    font-weight: bold;
    cursor: pointer;
    transition: background-color 0.3s ease, transform 0.2s ease;
}

.cta-section .cta-button:hover {
    background-color: #e67600;
    transform: translateY(-2px);
}

.cta-section img {
    max-width: 40%;
    min-width: 200px; 
    margin-left: 20px; 
    flex-shrink: 0; 
}

@media (max-width: 768px) {
    .cta-section {
        flex-wrap: wrap;
        text-align: center;
    }

    .cta-section .container {
        flex-direction: column; 
        align-items: center;
    }

    .cta-section .text, .cta-section img {
        max-width: 100%; 
        margin-bottom: 20px;
    }
}

.cta-section #input-wrapper {
    margin-top: 20px;
    display: flex;
    justify-content: flex-start;
    gap: 10px;
}

.cta-section #user-input {
    padding: 10px;
    font-size: 1rem;
    border: 1px solid #ccc;
    border-radius: 5px;
    flex: 1;
}

.cta-section #join-btn {
    padding: 10px 20px;
    font-size: 1rem;
    color: #fff;
    background-color: #0066ee;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    transition: background-color 0.3s ease;
}

.cta-section #join-btn:hover {
    background-color: #0056d2;
}


.appeal-section {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 80px 5%;
    background: #f9f9f9;
    flex-wrap: wrap;
}

.appeal-section .text {
    max-width: 50%;
    min-width: 300px;
}

.appeal-section h2 {
    font-size: 2.5rem;
    font-weight: bold;
    margin-bottom: 16px;
}

.appeal-section p {
    font-size: 1.2rem;
    line-height: 1.6;
    color: #555;
}

.appeal-section .author {
    font-style: italic;
    color: #888;
    margin-top: 16px;
}

.appeal-section img {
    max-width: 40%;
    min-width: 300px;
    border-radius: 16px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
}

@media (max-width: 768px) {
    .appeal-section {
        flex-direction: column;
        text-align: center;
    }

    .appeal-section .text, .appeal-section img {
        max-width: 100%;
        margin-bottom: 20px;
    }
}

.qna-section {
    background: #f9f9f9;
    padding: 40px 5%;
    text-align: left;
}

.qna-section h2 {
    font-size: 2.5rem;
    font-weight: bold;
    margin-bottom: 20px;
    text-align: center;
}

.qna-item {
    margin-bottom: 10px;
    border: none;
    border-radius: 12px;
    overflow: hidden;
    background: #fff;
    transition: all 0.3s ease;
}

.qna-title {
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 1.5rem;
    font-weight: bold;
    padding: 20px;
    cursor: pointer;
    color: #333;
    background: #fff;
    border-radius: 12px;
}

.qna-title .arrow-container {
    display: flex;
    justify-content: center;
    align-items: center;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background: #fff;
    transition: background 0.3s ease;
}

.qna-title .arrow-container:hover {
    background: #e0e0e0;
}

.qna-title .arrow {
    display: inline-block;
    width: 10px;
    height: 10px;
    border-left: 3px solid #333;
    border-bottom: 3px solid #333;
    transform: rotate(-45deg);
    transition: transform 0.3s ease;
}

.qna-title.active .arrow {
    transform: rotate(135deg);
}

.qna-content {
    display: none;
    font-size: 1.2rem;
    color: #555;
    padding: 20px;
    line-height: 1.6;
    background: #fff;
    border-radius: 12px;
    transition: max-height 0.3s ease;
}

.qna-content.open {
    display: block;
}

.qna-link {
    color: #0066ee;
    text-decoration: none;
    font-weight: bold;
}

.qna-link:hover {
    text-decoration: underline;
}


footer {
    background: rgba(0, 0, 0, 0.5);
    padding: 20px 5%;
    color: #fff;
    text-align: center;
}

footer p {
    margin: 1;
}

/* Add: for mobile */
@media (max-width: 480px) {
    body {
        font-size: 14px;
    }

    .container {
        padding: 0 10px;
    }

    .top-bar {
        padding: 10px;
    }

    .top-bar .cta-button {
        font-size: 0.9rem;
        padding: 8px 16px;
    }

    .navbar {
        display: none;
    }

    .navbar button {
        display: none;
    }

    .hero-section {
        flex-direction: column;
        text-align: center;
        padding: 60px 0;
        min-height: 20vh;
    }

    .hero-section img {
        display: none;
    }

    .hero-section h1 {
        font-size: 2rem;
    }

    .hero-section p {
        font-size: 1rem;
    }

    .features-section .feature {
        grid-template-columns: 1fr;
        text-align: center;
    }

    .features-section h2 {
        font-size: 2rem;
        margin-bottom: 20px;
    }

    .cta-section {
        flex-wrap: wrap;
        text-align: center;
        padding: 40px 5%;
    }

    .cta-section .text,
    .cta-section img {
        max-width: 100%;
        margin-bottom: 20px;
    }

    .cta-section .cta-button {
        font-size: 1rem;
        padding: 10px 20px;
    }

    .appeal-section {
        flex-direction: column;
        text-align: center;
        padding: 40px 5%;
    }

    .appeal-section .text,
    .appeal-section img {
        max-width: 100%;
        margin-bottom: 20px;
    }

    .review-section {
        padding: 60px 5%;
    }

    .review-section h2 {
        font-size: 2rem;
        margin-bottom: 20px;
    }

    .qna-section {
        padding: 20px 5%;
    }

    .qna-title {
        font-size: 1.2rem;
        padding: 15px;
    }

    .qna-content {
        font-size: 1rem;
        padding: 15px;
    }

    footer {
        padding: 15px 5%;
        font-size: 0.9rem;
    }
}