:root {
    --bg-color: #f9f9f9;
    --header-bg-gradient: linear-gradient(to right, #007aff, #00c6ff);
    --header-color: #ffffff;
    --text-color: #333333;
    --button-bg-color: #007aff;
    --button-color: #ffffff;
    --footer-bg-gradient: linear-gradient(to right, #007aff, #00c6ff);
    --footer-color: #ffffff;
}

body {
    font-family: 'SF Pro', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    margin: 0;
    padding: 0;
    overflow-x: hidden; /* Prevent horizontal scroll */
}

header {
    background: rgba(0, 0, 0, 0.3);
    padding: 0.5rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    position: fixed;
    top: 0;
    width: 100%;
    box-sizing: border-box;
    z-index: 2;
}

#header-title-container {
    display: flex;
    align-items: center;
}

#header-title {
    margin: 0;
    font-size: 2rem; 
    font-weight: 700; 
    color: var(--header-color);
    text-shadow: 1px 1px 2px rgba(0, 0, 0, 0.3);
    letter-spacing: 1px; 
    font-family: 'SF Pro', sans-serif; 
}

#app-icon {
    width: 40px;
    height: 40px;
    margin-right: 1rem;
    display: inline-block;
    vertical-align: middle;
}

nav {
    display: flex;
    align-items: center;
}

nav a {
    margin-left: 1rem;
    color: var(--header-color);
    text-decoration: none;
    font-weight: 500;
    font-size: 1rem;
}

.language-selector {
    margin-left: 1rem;
    margin-right: 1rem;
    padding: 0.5rem;
    border-radius: 5px;
    border: 1px solid #ddd;
    background-color: #fff;
    font-size: 1rem;
    color: #000;
}

.color-selector {
    position: relative;
    margin-left: 1rem;
    cursor: pointer;
}

.language-selector, .color-selector {
    display: none;
}

.current-color {
    width: 30px;
    height: 20px;
    border-radius: 10px;
    display: inline-block;
    border: 2px solid #333;
    vertical-align: middle;
}

.color-dropdown {
    display: none;
    position: absolute;
    top: 30px;
    left: 0;
    background-color: #fff;
    border: 1px solid #ddd;
    border-radius: 5px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
    padding: 0.5rem;
    z-index: 3;
}

.color-dropdown .color-block {
    width: 30px;
    height: 20px;
    border-radius: 10px;
    display: inline-block;
    margin: 5px;
    cursor: pointer;
}

.banner {
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
    padding: 4rem 2rem;
    background-image: url('banner-background.jpg');
    background-size: cover;
    background-position: center;
    height: 45vh; 
    width: 100%;
    max-width: 100%; 
    box-sizing: border-box;
    position: relative;
}

.banner-icon {
    width: 96px;
    height: 96px;
    margin-bottom: 0rem; 
}

.banner h1 {
    font-size: 2.5rem;
    margin-top: 0.2rem; 
    margin-bottom: 1rem;
    font-weight: 700;
    color: #ffffff;
    text-shadow: 2px 2px 10px rgba(0, 0, 0, 0.5);
}

.banner p {
    font-size: 1.2rem;
    color: #ffffff;
    margin-bottom: 2rem;
    font-weight: 400;
    text-shadow: 1px 1px 2px rgba(0, 0, 0, 0.5);
}

.download-button {
    padding: 1rem 2rem;
    background-color: var(--button-bg-color);
    color: var(--button-color);
    text-decoration: none;
    border-radius: 25px;
    font-weight: 600;
    font-size: 1rem;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
}

.features {
    padding: 4rem 2rem;
    text-align: center;
}

.features h2 {
    font-size: 2rem;
    margin-bottom: 2rem;
    font-weight: 600;
}

.feature-item {
    display: inline-block;
    width: 30%;
    min-width: 300px;
    margin: 1rem;
    text-align: left;
    padding: 1rem;
    background-color: #ffffff;
    border-radius: 15px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
    box-sizing: border-box; 
     
}

.feature-item img {
    width: 100%;
    height: auto;
    border-radius: 15px;
}

.feature-item h3 {
    font-size: 1.5rem;
    margin-top: 1rem;
    font-weight: 600;
}

.feature-item p {
    font-size: 1rem;
    color: #555555;
    font-weight: 400;
}

.download {
    text-align: center;
    padding: 4rem 2rem;
    max-width: 100%; 
}

.download a {
    display: inline-block;
    margin: 1rem;
    padding: 1rem 2rem;
    background-color: var(--button-bg-color);
    color: var(--button-color);
    text-decoration: none;
    border-radius: 25px;
    font-weight: 600;
    font-size: 1rem;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
}

.about {
    padding: 4rem 2rem;
    text-align: center;
    max-width: 100%; 
}

.about h2 {
    font-size: 2rem;
    margin-bottom: 2rem;
    font-weight: 600;
}

.about p {
    font-size: 1.2rem;
    color: #555555;
    max-width: 800px;
    margin: 0 auto;
    font-weight: 400;
    text-align: left;
    display: inline-block;
    width: 80%;
    margin: 1rem;
    text-align: left;
    padding: 1rem;
    background-color: #ffffff;
    border-radius: 15px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
    box-sizing: border-box;
}

footer {
    background: var(--footer-bg-gradient);
    padding: 1rem;
    text-align: center;
    color: var(--footer-color);
    margin-top: 2rem;
    font-weight: 500;
    box-sizing: border-box;
    max-width: 100%; 
}

.footer-link {
    color: var(--footer-color);
    text-decoration: none;
    margin-left: 10px;
}

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

@media (max-width: 768px) {

    .feature-item {
        width: 90%; /* 在小屏幕上接近全宽显示 */
        min-width: auto; /* 覆盖 min-width 以允许全宽显示 */
        /* margin: 1rem auto; 在父容器内居中 */
        text-align: center; /* 在小屏幕上居中对齐 */

        margin-left: auto;
        margin-right: auto;
    }
    .feature-item img, .feature-item h3, .feature-item p {
        text-align: center; /* 确保子元素也居中对齐 */
        margin: 0 auto; /* 确保子元素在水平居中 */
    }

    header {
        flex-direction: row;
        justify-content: space-between;
    }

    nav {
        display: none;
        flex-direction: column;
        align-items: center;
        position: fixed;
        top: 60px;
        right: 0;
        background-color: rgba(0, 0, 0, 0.9);
        width: 100%;
        height: 100%;
        z-index: 3;
        overflow-y: auto;
        padding-top: 20px;
    }

    nav a {
        margin: 10px 0;
        color: #ffffff;
        font-size: 1.2rem;
    }

    .menu-toggle {
        display: block;
        cursor: pointer;
        background: none;
        border: none;
        color: #fff;
        font-size: 1.5rem;
        z-index: 4;
    }

    .menu-toggle span {
        display: block;
        width: 25px;
        height: 3px;
        margin: 5px;
        background: #fff;
        transition: all 0.3s;
    }

    .menu-toggle.active span:nth-child(1) {
        transform: translateY(8px) rotate(45deg);
    }

    .menu-toggle.active span:nth-child(2) {
        opacity: 0;
    }

    .menu-toggle.active span:nth-child(3) {
        transform: translateY(-8px) rotate(-45deg);
    }

    nav.active {
        display: flex;
    }
}

@media (min-width: 769px) {
    .menu-toggle {
        display: none;
    }
}

@media (max-width: 480px) {
    .banner h1 {
        font-size: 2rem;
    }
    .banner p {
        font-size: 1rem;
    }
    .features h2 {
        font-size: 1.5rem;
    }
    .feature-item {
        width: 100%;
    }
}