* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'PingFang SC', 'Helvetica Neue', Arial, sans-serif;
}

body {
    background: #f5f7fa;
    color: #333;
    line-height: 1.6;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    padding: 20px;
}

.phone-container {
    width: 100%;
    max-width: 400px;
    height: 80vh;
    min-height: 700px;
    background: #f9f9f9;
    border-radius: 30px;
    box-shadow: 0 10px 50px rgba(0, 0, 0, 0.2);
    overflow: hidden;
    position: relative;
    display: flex;
    flex-direction: column;
}

.status-bar {
    height: 50px;
    display: none;
    justify-content: space-between;
    align-items: center;
    padding: 0 20px;
    border-bottom: 1px solid #eee;
}

.time {
    font-weight: 600;
    font-size: 14px;
}

.status-icons {
    display: flex;
    gap: 10px;
}

.status-icons i {
    font-size: 12px;
}

.content {
    flex: 1;
    overflow-y: auto;
    padding: 20px;
    position: relative;
    scrollbar-width: none;
    -ms-overflow-style: none;
}

.content::-webkit-scrollbar {
    display: none;
}

.login-container {
    display: flex;
    flex-direction: column;
    height: 100%;
}

.app-icon {
    width: 80px;
    height: 80px;
    background: linear-gradient(135deg, #6e8efb, #a777e3);
    border-radius: 20px;
    overflow: hidden;
    margin: 40px auto 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 30px;
}

h1 {
    text-align: center;
    margin-bottom: 40px;
    color: #333;
    font-weight: 600;
}

.input-group {
    margin-bottom: 20px;
}

.input-group label {
    display: block;
    margin-bottom: 8px;
    font-size: 14px;
    color: #666;
    font-weight: 500;
}

.input-group input {
    width: 100%;
    padding: 15px;
    border: 1px solid #ddd;
    border-radius: 10px;
    font-size: 16px;
    transition: border-color 0.3s;
}

.input-group input:focus {
    border-color: #6e8efb;
    outline: none;
}

.login-btn {
    background: linear-gradient(135deg, #6e8efb, #a777e3);
    color: white;
    border: none;
    padding: 15px;
    border-radius: 10px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    margin-top: 30px;
    transition: transform 0.2s, box-shadow 0.2s;
}

.login-btn:active {
    transform: scale(0.98);
}

.remember-forgot {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: 15px;
    font-size: 14px;
}

.forgot {
    color: #6e8efb;
    text-decoration: none;
}

.courses-container {
    display: none;
    height: 100%;
}

.course-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 25px;
}

.course-header h2 {
    font-size: 22px;
    font-weight: 600;
}

.search-box {
    display: flex;
    align-items: center;
    background: white;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.05);
    border-radius: 20px;
    padding: 8px 15px;
    width: 100%;
    margin-bottom: 20px;
}

.search-box input {
    flex: 1;
    border: none;
    background: transparent;
    padding: 5px;
    outline: none;
}

.course-list {
    display: grid;
    gap: 15px;
    padding-bottom: 20vh;
}

.course-card {
    background: white;
    border-radius: 15px;
    padding: 15px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.05);
    display: flex;
    gap: 15px;
    transition: transform 0.2s;
}

.course-card:active {
    transform: scale(0.98);
}

.course-icon {
    width: 60px;
    height: 60px;
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 20px;
    flex-shrink: 0;
    object-fit: cover;
}

.course-info {
    flex: 1;
}

.course-title {
    font-weight: 600;
    margin-bottom: 5px;
}

.course-desc {
    font-size: 13px;
    color: #666;
    margin-bottom: 8px;
}

.bottom-nav {
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    background: white;
    display: flex;
    justify-content: space-around;
    padding: 15px;
    border-top: 1px solid #eee;
}

.nav-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    color: #888;
    font-size: 12px;
}

.nav-item.active {
    color: #6e8efb;
}

.nav-item i {
    font-size: 20px;
    margin-bottom: 5px;
}

.loader {
    display: none;
    text-align: center;
    margin-top: 30px;
}

.loader .spinner {
    width: 40px;
    height: 40px;
    border: 4px solid #f3f3f3;
    border-top: 4px solid #6e8efb;
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin: 0 auto 15px;
}

.btn-disabled {
    background: #888 !important;
    cursor: not-allowed !important;
}

@keyframes spin {
    0% {
        transform: rotate(0deg);
    }

    100% {
        transform: rotate(360deg);
    }
}

@media (max-width: 768px) {
    body {
        padding: 0;
    }

    .content {
        padding: 20px 32px;
    }

    .phone-container {
        max-width: 100%;
        height: 100vh;
        border-radius: 0;
        box-shadow: none;
    }
}

@media (min-width: 768px) {
    .status-bar {
        display: flex;
    }

    body::before {
        content: "正在模拟手机端体验，请在手机浏览器上使用完整功能！";
        position: fixed;
        top: 0;
        left: 0;
        right: 0;
        background: #6e8efb;
        color: white;
        text-align: center;
        padding: 10px;
        font-size: 14px;
        z-index: 100;
    }
}