/* ========== 公共基础样式 ========== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}
body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #f5f7fa;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}
main {
    flex: 1;
}

/* ========== Header ========== */
header {
    background: #fff;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
    padding: 15px 0;
    position: sticky;
    top: 0;
    z-index: 100;
}
.header-inner {
    max-width: 1000px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    position: relative;
}
.brand {
    display: flex;
    align-items: center;
    gap: 12px;
}
.brand-logo {
    width: 44px;
    height: 44px;
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
}
.brand-logo img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    border-radius: 12px;
}
.brand-text h1 {
    font-size: 20px;
    color: #222;
}
.brand-text p {
    font-size: 12px;
    color: #999;
}
nav a {
    color: #555;
    text-decoration: none;
    margin-left: 24px;
    font-size: 14px;
    transition: color 0.2s;
}
nav a:hover {
    color: #ff6b35;
}

/* ========== 移动端菜单按钮 ========== */
.menu-toggle {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    padding: 10px;
    flex-direction: column;
    gap: 5px;
}
.menu-toggle span {
    display: block;
    width: 24px;
    height: 2px;
    background: #555;
    transition: all 0.3s;
}
.menu-toggle.active span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
}
.menu-toggle.active span:nth-child(2) {
    opacity: 0;
}
.menu-toggle.active span:nth-child(3) {
    transform: rotate(-45deg) translate(5px, -5px);
}

/* ========== 按钮 ========== */
.btn-group {
    display: flex;
    gap: 12px;
    margin-top: 16px;
}
.btn-group .btn {
    flex: 1;
    padding: 12px 16px;
    border-radius: 8px;
    font-size: 14px;
    font-weight: 500;
    text-align: center;
    text-decoration: none;
    cursor: pointer;
    transition: all 0.2s;
    border: none;
}
.btn-primary {
    background: linear-gradient(135deg, #ff6b35 0%, #ff8c5a 100%);
    color: #fff;
    box-shadow: 0 2px 8px rgba(255, 107, 53, 0.3);
}
.btn-primary:hover {
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(255, 107, 53, 0.4);
}
.btn-secondary {
    background: #f5f7fa;
    color: #555;
    border: 1px solid #e0e0e0;
}
.btn-secondary:hover {
    background: #e8eaed;
}

/* ========== 二维码弹窗 ========== */
.qr-modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.5);
    z-index: 1000;
    align-items: center;
    justify-content: center;
}
.qr-modal.active {
    display: flex;
}
.qr-modal-content {
    background: #fff;
    border-radius: 16px;
    padding: 30px;
    text-align: center;
    max-width: 320px;
    width: 90%;
    position: relative;
}
.qr-modal-close {
    position: absolute;
    top: 15px;
    right: 15px;
    background: none;
    border: none;
    font-size: 24px;
    color: #999;
    cursor: pointer;
    width: 30px;
    height: 30px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    transition: all 0.2s;
}
.qr-modal-close:hover {
    background: #f0f0f0;
    color: #333;
}
.qr-modal h4 {
    font-size: 18px;
    margin-bottom: 20px;
    color: #222;
}
.qr-modal img {
    width: 200px;
    height: 200px;
    border-radius: 8px;
    border: 1px solid #eee;
}
.qr-modal p {
    margin-top: 12px;
    font-size: 13px;
    color: #888;
}

/* ========== Footer ========== */
footer {
    background: #222;
    color: #aaa;
    text-align: center;
    padding: 30px 20px;
    font-size: 13px;
}
footer a {
    color: #ccc;
    text-decoration: none;
    margin: 0 10px;
}
footer a:hover {
    color: #fff;
}

/* ========== 响应式：600px 以下 ========== */
@media (max-width: 600px) {
    .header-inner {
        padding: 0 15px;
    }
    .brand-text h1 {
        font-size: 18px;
    }
    .brand-text p {
        font-size: 11px;
    }
    .brand-logo {
        width: 38px;
        height: 38px;
    }
    .menu-toggle {
        display: flex;
    }
    nav {
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: #fff;
        box-shadow: 0 4px 12px rgba(0,0,0,0.1);
        padding: 0;
        max-height: 0;
        overflow: hidden;
        transition: max-height 0.3s ease;
    }
    nav.active {
        max-height: 200px;
    }
    nav a {
        display: block;
        margin: 0;
        padding: 15px 20px;
        border-bottom: 1px solid #f0f0f0;
        font-size: 15px;
    }
    nav a:last-child {
        border-bottom: none;
    }
    footer {
        padding: 25px 15px;
        font-size: 12px;
        line-height: 1.8;
    }
    footer a {
        margin: 0 8px;
        font-size: 12px;
    }
}

/* ========== 响应式：480px 以下 ========== */
@media (max-width: 480px) {
    .qr-modal-content {
        padding: 20px;
    }
    .qr-modal img {
        width: 180px;
        height: 180px;
    }
    .btn-group {
        flex-direction: column;
    }
    .btn-group .btn {
        width: 100%;
    }
}