:root {
    --primary-color: #2563eb;    /* 蓝色主题，体现专业性 */
    --text-color: #1f2937;
    --background-color: #ffffff;
    --container-width: 1200px;
}

.container {
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 0 1rem;
}

.header {
    background-color: var(--background-color);
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
    padding: 1rem 0;
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 100;
}

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

.header__logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    text-decoration: none;
    color: var(--text-color);
}

.header__logo-img {
    height: 40px;
    width: auto;
}

.header__logo-text {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
}

.header__tagline {
    font-size: 1rem;
    color: #6b7280;
    margin-left: 1rem;
    padding-left: 1rem;
    border-left: 2px solid #e5e7eb;
}

/* 响应式设计 */
@media (max-width: 640px) {
    .header__tagline {
        display: none;
    }
    
    .header__logo-img {
        height: 32px;
    }
    
    .header__logo-text {
        font-size: 1.25rem;
    }
}

/* Video Section */
.video {
    padding: 4rem 0;
    background-color: #f3f4f6;
}

.video__title {
    text-align: center;
    font-size: 2rem;
    font-weight: 700;
    color: var(--text-color);
    margin-bottom: 2rem;
}

.video__grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 2rem;
    max-width: 100%;
}

.video__item {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.video__wrapper {
    position: relative;
    padding-bottom: 56.25%; /* 16:9 宽高比 */
    height: 0;
    overflow: hidden;
    border-radius: 0.5rem;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
}

.video__wrapper iframe {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    border: none;
}

.video__subtitle {
    text-align: center;
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-color);
}

/* 响应式设计 */
@media (max-width: 768px) {
    .video__grid {
        grid-template-columns: 1fr;  /* 手机端单列显示 */
    }

    .video__title {
        font-size: 1.5rem;
    }

    .video__subtitle {
        font-size: 1rem;
    }

    .video {
        padding: 2rem 0;
    }
}

/* Features Section */
.features {
    padding: 6rem 0;
    background-color: var(--background-color);
}

.features__title {
    text-align: center;
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--text-color);
    margin-bottom: 4rem;
}

.features__grid {
    display: flex;
    flex-direction: column;
    gap: 4rem;
}

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

.features__image {
    border-radius: 1rem;
    overflow: hidden;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
}

.features__image img {
    width: 100%;
    height: auto;
    display: block;
}

.features__content h3 {
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--text-color);
    margin-bottom: 1rem;
}

.features__content p {
    font-size: 1.125rem;
    line-height: 1.75;
    color: #4b5563;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .features {
        padding: 3rem 0;
    }

    .features__title {
        font-size: 2rem;
        margin-bottom: 2rem;
    }

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

    .features__image {
        max-width: 300px;
        margin: 0 auto;
    }

    .features__content h3 {
        font-size: 1.5rem;
    }

    .features__content p {
        font-size: 1rem;
    }

    .features__grid {
        gap: 3rem;
    }
}

/* Hero Section */
.hero {
    padding: 8rem 0 4rem;
    background: linear-gradient(to bottom right, #f8fafc, #e2e8f0);
    overflow: hidden;
}

.hero__container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
}

.hero__content {
    max-width: 600px;
}

.hero__title {
    font-size: 3.5rem;
    font-weight: 800;
    line-height: 1.2;
    color: var(--text-color);
    margin-bottom: 1.5rem;
    background: linear-gradient(to right, #1e40af, #3b82f6);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero__subtitle {
    font-size: 1.25rem;
    line-height: 1.6;
    color: #4b5563;
    margin-bottom: 2.5rem;
}

.hero__button {
    display: inline-flex;
    align-items: center;
    gap: 1rem;
    background-color: var(--primary-color);
    color: white;
    padding: 1rem 2rem;
    border-radius: 0.75rem;
    text-decoration: none;
    transition: transform 0.2s, box-shadow 0.2s;
    box-shadow: 0 4px 6px -1px rgba(37, 99, 235, 0.2);
}

.hero__button:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 12px -1px rgba(37, 99, 235, 0.3);
}

.hero__button-text {
    display: flex;
    flex-direction: column;
}

.hero__button-subtext {
    font-size: 0.875rem;
    opacity: 0.9;
}

.hero__button-icon {
    font-size: 1.5rem;
}

.hero__image {
    position: relative;
    border-radius: 1rem;
    overflow: hidden;
    box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1),
                0 10px 10px -5px rgba(0, 0, 0, 0.04);
}

.hero__image img {
    width: 100%;
    height: auto;
    display: block;
    transform: scale(1.02); /* 轻微放大，增加视觉效果 */
}

/* 响应式设计 */
@media (max-width: 1024px) {
    .hero__title {
        font-size: 2.5rem;
    }

    .hero__subtitle {
        font-size: 1.125rem;
    }
}

@media (max-width: 768px) {
    .hero {
        padding: 6rem 0 3rem;
    }

    .hero__container {
        grid-template-columns: 1fr;
        gap: 2rem;
        text-align: center;
    }

    .hero__content {
        max-width: 100%;
    }

    .hero__title {
        font-size: 2rem;
    }

    .hero__image {
        max-width: 80%;
        margin: 0 auto;
    }

    .hero__button {
        width: 100%;
        justify-content: center;
    }
}

/* Content Section */
.content {
    padding: 4rem 0;
    background-color: #f8fafc;
}

.content__main {
    max-width: 800px;
    margin: 0 auto;
}

.content__title {
    font-size: 2.5rem;
    font-weight: 800;
    color: var(--text-color);
    margin-bottom: 2rem;
    text-align: center;
}

.content__section {
    margin-bottom: 3rem;
}

.content__section h2 {
    font-size: 2rem;
    font-weight: 700;
    color: var(--text-color);
    margin-bottom: 1.5rem;
}

.content__section h3 {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-color);
    margin: 1.5rem 0 1rem;
}

.content__section h4 {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-color);
    margin: 1rem 0 0.75rem;
}

.content__section p {
    font-size: 1.125rem;
    line-height: 1.75;
    color: #4b5563;
    margin-bottom: 1rem;
}

.content__features {
    list-style-type: none;
    padding: 0;
    margin: 1rem 0;
}

.content__features li {
    padding: 0.75rem 0;
    padding-left: 1.5rem;
    position: relative;
    font-size: 1.125rem;
    color: #4b5563;
}

.content__features li::before {
    content: "•";
    position: absolute;
    left: 0;
    color: var(--primary-color);
}

.content__faq {
    margin-bottom: 2rem;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .content {
        padding: 2rem 0;
    }

    .content__title {
        font-size: 2rem;
    }

    .content__section h2 {
        font-size: 1.75rem;
    }

    .content__section h3 {
        font-size: 1.25rem;
    }

    .content__section h4 {
        font-size: 1.125rem;
    }

    .content__section p {
        font-size: 1rem;
    }
}