/* ══ CSS 变量：品牌色统一管理 ══ */
:root {
    --brand:    #1854FF;
    --brand-dk: #1240CC;
    --brand-bg: #EEF2FF;
    --teal:     #36CFC9;
    --teal-bg:  #E6FFFE;
    --dark:     #1D2129;
    --gray:     #6B7280;
    --gray-lt:  #9CA3AF;
    --border:   #E5E7EB;
    --bg:       #F7F8FA;
}

/* ══ 全局基础 ══ */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
body {
    font-family: system-ui, -apple-system, "PingFang SC", "Noto Sans SC", sans-serif;
    color: var(--dark);
    background: #fff;
    -webkit-font-smoothing: antialiased;
}

/* ══ 导航栏 ══ */
.nav {
    position: sticky;
    top: 0;
    z-index: 200;
    background: #fff;
    border-bottom: 1px solid var(--border);
    padding: 0 5%;
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 64px;
}
.nav-logo {
    font-size: 18px;
    font-weight: 700;
    color: var(--brand);
    letter-spacing: -0.3px;
    text-decoration: none;
}
.nav-links { display: flex; gap: 32px; align-items: center; }
.nav-links a {
    font-size: 14px;
    color: var(--gray);
    text-decoration: none;
    transition: color .15s;
}
.nav-links a:hover { color: var(--brand); }
.nav-cta {
    background: var(--brand);
    color: #fff;
    padding: 8px 20px;
    border-radius: 6px;
    font-size: 14px;
    font-weight: 500;
    text-decoration: none;
    transition: background .15s;
}
.nav-cta:hover { background: var(--brand-dk); }

/* ══ 汉堡菜单（移动端） ══ */
.nav-burger {
    display: none;
    cursor: pointer;
    flex-direction: column;
    gap: 5px;
    padding: 4px;
}
.nav-burger span {
    display: block;
    width: 22px;
    height: 2px;
    background: var(--dark);
    border-radius: 2px;
}
.nav-mobile {
    display: none;
    flex-direction: column;
    background: #fff;
    padding: 12px 5% 16px;
    border-bottom: 1px solid var(--border);
}
.nav-mobile a {
    padding: 11px 0;
    font-size: 15px;
    color: var(--dark);
    text-decoration: none;
    border-bottom: 1px solid #F3F4F6;
}
.nav-mobile a:last-child { border-bottom: none; }
.nav-mobile.open { display: flex; }

@media (max-width: 768px) {
    .nav-links { display: none; }
    .nav-burger { display: flex; }
}

/* ══ Hero 首屏 ══ */
.hero {
    background: var(--bg);
    padding: 96px 5% 88px;
    text-align: center;
}
.hero-tag {
    display: inline-block;
    font-size: 13px;
    color: var(--brand);
    background: var(--brand-bg);
    padding: 4px 14px;
    border-radius: 20px;
    margin-bottom: 24px;
    letter-spacing: .5px;
}
.hero h1 {
    font-size: clamp(30px, 5vw, 52px);
    font-weight: 700;
    color: var(--dark);
    line-height: 1.22;
    letter-spacing: -1px;
    margin-bottom: 20px;
}
.hero h1 em { font-style: normal; color: var(--brand); }
.hero p {
    font-size: 17px;
    color: var(--gray);
    max-width: 560px;
    margin: 0 auto 40px;
    line-height: 1.75;
}
.hero-btns { display: flex; gap: 12px; justify-content: center; flex-wrap: wrap; }
a.btn-primary, a.btn-outline {
    display: inline-block;
    padding: 12px 28px;
    border-radius: 6px;
    font-size: 15px;
    font-weight: 500;
    text-decoration: none;
    border: 1.5px solid var(--brand);
    line-height: 1.5;
    transition: background .15s, border-color .15s;
    min-width: 180px;
    text-align: center;
}
a.btn-primary {
    background: var(--brand);
    color: #fff;
}
a.btn-primary:hover { background: var(--brand-dk); border-color: var(--brand-dk); }
a.btn-outline {
    background: transparent;
    color: var(--brand);
}
a.btn-outline:hover { background: var(--brand-bg); }

/* ══ Hero 信任标签 ══ */
.hero-trust {
    margin-top: 36px;
    padding-top: 20px;
    border-top: 1px solid var(--border);
    display: inline-block;
    font-size: 13px;
    color: var(--gray);
    letter-spacing: 0.2px;
}

/* ══ Section 通用 ══ */
.section    { padding: 80px 5%; }
.sec-white  { background: #fff; }
.sec-gray   { background: var(--bg); }
.sec-title {
    font-size: clamp(22px, 3vw, 32px);
    font-weight: 700;
    color: var(--dark);
    text-align: center;
    margin-bottom: 12px;
    letter-spacing: -0.5px;
}
.sec-sub {
    font-size: 15px;
    color: var(--gray);
    text-align: center;
    margin-bottom: 52px;
    line-height: 1.7;
}

/* ══ 咨询表单 ══ */
.contact-wrap {
    max-width: 560px;
    margin: 0 auto;
    background: #fff;
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 40px;
}
.form-row { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.form-group { margin-bottom: 18px; }
.form-label {
    display: block;
    font-size: 13px;
    color: var(--gray);
    margin-bottom: 6px;
    font-weight: 500;
}
.form-input, .form-select {
    width: 100%;
    padding: 10px 14px;
    font-size: 14px;
    border: 1.5px solid var(--border);
    border-radius: 6px;
    outline: none;
    color: var(--dark);
    background: #FAFAFA;
    transition: border-color .15s, background .15s;
    font-family: inherit;
}
.form-input:focus, .form-select:focus { border-color: var(--brand); background: #fff; }
.form-textarea { min-height: 96px; resize: vertical; }
.form-submit {
    width: 100%;
    background: var(--brand);
    color: #fff;
    padding: 13px;
    border: none;
    border-radius: 6px;
    font-size: 15px;
    font-weight: 500;
    cursor: pointer;
    transition: background .15s;
    margin-top: 6px;
    font-family: inherit;
}
.form-submit:hover:not(:disabled) { background: var(--brand-dk); }
.form-submit:disabled { background: var(--teal); cursor: default; }

@media (max-width: 600px) {
    .contact-wrap { padding: 28px 20px; }
    .form-row { grid-template-columns: 1fr; }
}

/* ══ Flash 消息 ══ */
.flash-msg {
    max-width: 560px;
    margin: 0 auto 16px;
    padding: 12px 18px;
    border-radius: 8px;
    font-size: 14px;
    font-weight: 500;
    text-align: center;
    transition: opacity 0.3s ease;
}
.flash-msg.success {
    background: #ECFDF5;
    color: #065F46;
    border: 1px solid #A7F3D0;
}
.flash-msg.error {
    background: #FEF2F2;
    color: #991B1B;
    border: 1px solid #FECACA;
}

/* ══ 页脚 ══ */
.site-footer {
    background: var(--dark);
    color: #9CA3AF;
    text-align: center;
    padding: 36px 5%;
    font-size: 13px;
    line-height: 2;
}
.site-footer a {
    color: #9CA3AF;
    text-decoration: none;
    margin: 0 8px;
    transition: color .15s;
}
.site-footer a:hover { color: #fff; }
.footer-links { margin-bottom: 6px; }