/* ===== SpeakEnglishAI 页面样式 ===== */
/* 复用 style.css 的结构体系,通过 body.ai-page 作用域把绿色主题覆盖为紫色,
   保持同一网站的产品家族感;新增 section(三步/适合人群)与主页导流横幅样式 */

/* --- 紫色主题变量(覆盖式) --- */
body.ai-page .navbar {
    border-bottom: 1px solid rgba(124, 58, 237, 0.1);
}

body.ai-page .nav-link:hover {
    color: #7C3AED;
    background: rgba(124, 58, 237, 0.08);
}

body.ai-page .logo-emoji {
    font-size: 26px;
}

body.ai-page .logo-text {
    font-size: 19px;
}

body.ai-page .hero {
    background:
        radial-gradient(ellipse at 20% 50%, rgba(124, 58, 237, 0.12) 0%, transparent 50%),
        radial-gradient(ellipse at 80% 20%, rgba(124, 58, 237, 0.08) 0%, transparent 40%),
        radial-gradient(ellipse at 50% 100%, rgba(124, 58, 237, 0.06) 0%, transparent 50%),
        linear-gradient(175deg, #e9defc 0%, #f4f0ff 35%, #ffffff 100%);
}

body.ai-page .hero::before {
    background-image: radial-gradient(circle, rgba(124, 58, 237, 0.07) 1px, transparent 1px);
}

body.ai-page .hero-title {
    color: #7C3AED;
    font-size: 44px;
    text-shadow: 0 2px 0 rgba(91, 33, 182, 0.12);
}

body.ai-page .badge-free {
    background: linear-gradient(135deg, #7C3AED, #6D28D9);
    box-shadow: 0 3px 0 #5B21B6, 0 4px 12px rgba(124, 58, 237, 0.3);
}

body.ai-page .qr-card {
    box-shadow:
        0 2px 0 rgba(0, 0, 0, 0.03),
        0 8px 32px rgba(124, 58, 237, 0.12),
        0 0 0 1px rgba(124, 58, 237, 0.06);
}

body.ai-page .qr-card:hover {
    box-shadow:
        0 2px 0 rgba(0, 0, 0, 0.03),
        0 12px 40px rgba(124, 58, 237, 0.18),
        0 0 0 1px rgba(124, 58, 237, 0.08);
}

body.ai-page .feature-card:hover {
    border-color: rgba(124, 58, 237, 0.3);
}

body.ai-page .feature-card.feature-free {
    border-color: #7C3AED;
    background: linear-gradient(135deg, #f8f5ff, #fff);
}

body.ai-page .feature-card.feature-free:hover {
    border-color: #7C3AED;
    box-shadow: 0 12px 32px rgba(124, 58, 237, 0.15);
}

body.ai-page .philosophy {
    background:
        radial-gradient(ellipse at 30% 50%, rgba(255, 255, 255, 0.1) 0%, transparent 50%),
        radial-gradient(ellipse at 70% 80%, rgba(0, 0, 0, 0.05) 0%, transparent 40%),
        linear-gradient(135deg, #7C3AED 0%, #6D28D9 50%, #5B21B6 100%);
}

body.ai-page .footer-search strong {
    color: #A78BFA;
}

body.ai-page .footer-link,
.footer-link {
    color: #A78BFA;
    text-decoration: none;
    font-weight: 600;
}

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

/* --- 新增:三步流程 --- */
.how {
    padding: 80px 0;
    background: #fff;
}

.steps {
    display: flex;
    align-items: stretch;
    justify-content: center;
    gap: 18px;
    max-width: 920px;
    margin: 0 auto;
}

.step-card {
    flex: 1;
    background: #fff;
    border: 2px solid #f0f0f0;
    border-radius: 18px;
    padding: 32px 22px;
    text-align: center;
    box-shadow: 0 2px 12px rgba(0, 0, 0, 0.04);
    transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}

.step-card:hover {
    transform: translateY(-6px);
    border-color: rgba(124, 58, 237, 0.3);
    box-shadow: 0 12px 32px rgba(0, 0, 0, 0.1);
}

.step-num {
    width: 48px;
    height: 48px;
    margin: 0 auto 16px;
    border-radius: 50%;
    background: linear-gradient(135deg, #7C3AED, #6D28D9);
    color: #fff;
    font-size: 22px;
    font-weight: 800;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 3px 0 #5B21B6;
}

.step-card h3 {
    font-size: 18px;
    color: #333;
    margin-bottom: 8px;
    font-weight: 700;
}

.step-card p {
    font-size: 14px;
    color: #999;
    line-height: 1.7;
}

.step-arrow {
    align-self: center;
    font-size: 26px;
    color: #d8c9f7;
    flex-shrink: 0;
}

/* --- 新增:适合人群 --- */
.audience {
    padding: 80px 0;
    background: #faf8ff;
}

.audience-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 20px;
}

.audience-card {
    background: #fff;
    border: 2px solid #f0f0f0;
    border-radius: 18px;
    padding: 30px 20px;
    text-align: center;
    transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}

.audience-card:hover {
    transform: translateY(-6px);
    border-color: rgba(124, 58, 237, 0.3);
    box-shadow: 0 12px 32px rgba(0, 0, 0, 0.08);
}

.audience-icon {
    font-size: 38px;
    margin-bottom: 12px;
    display: block;
}

.audience-card h3 {
    font-size: 17px;
    color: #333;
    margin-bottom: 6px;
    font-weight: 700;
}

.audience-card p {
    font-size: 13px;
    color: #999;
    line-height: 1.7;
}

/* --- 新增:主页的 AI 产品导流横幅 + 导航 CTA --- */
.promo-banner {
    padding: 0 0 72px;
    background: #fff;
}

.promo-card {
    display: flex;
    align-items: center;
    gap: 28px;
    background: linear-gradient(135deg, #f8f5ff 0%, #fff 60%, #f3ecff 100%);
    border: 2px solid rgba(124, 58, 237, 0.25);
    border-radius: 22px;
    padding: 32px 36px;
    text-decoration: none;
    transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
    position: relative;
    overflow: hidden;
}

.promo-card:hover {
    transform: translateY(-4px);
    border-color: #7C3AED;
    box-shadow: 0 16px 44px rgba(124, 58, 237, 0.18);
}

.promo-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    bottom: 0;
    width: 6px;
    background: linear-gradient(180deg, #7C3AED, #5B21B6);
}

.promo-badge {
    flex-shrink: 0;
    background: linear-gradient(135deg, #7C3AED, #6D28D9);
    color: #fff;
    font-size: 13px;
    font-weight: 700;
    padding: 6px 14px;
    border-radius: 20px;
    letter-spacing: 1px;
    box-shadow: 0 2px 0 #5B21B6;
}

.promo-body {
    flex: 1;
}

.promo-title {
    font-size: 20px;
    font-weight: 800;
    color: #333;
    margin-bottom: 4px;
}

.promo-title strong {
    color: #7C3AED;
}

.promo-desc {
    font-size: 14px;
    color: #888;
    line-height: 1.7;
}

.promo-cta {
    flex-shrink: 0;
    font-size: 15px;
    font-weight: 700;
    color: #fff;
    background: linear-gradient(135deg, #7C3AED, #6D28D9);
    padding: 12px 26px;
    border-radius: 12px;
    box-shadow: 0 3px 0 #5B21B6;
    white-space: nowrap;
}

.nav-cta {
    color: #fff !important;
    background: linear-gradient(135deg, #7C3AED, #6D28D9);
    box-shadow: 0 2px 0 #5B21B6;
}

.nav-cta:hover {
    color: #fff !important;
    background: linear-gradient(135deg, #6D28D9, #5B21B6) !important;
}

/* --- 响应式 --- */
@media (max-width: 768px) {
    body.ai-page .hero-title {
        font-size: 34px;
    }

    .steps {
        flex-direction: column;
        align-items: center;
    }

    .step-card {
        width: 100%;
        max-width: 420px;
    }

    .step-arrow {
        transform: rotate(90deg);
        margin: -6px 0;
    }

    .audience-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 480px) {
    body.ai-page .hero-title {
        font-size: 28px;
        letter-spacing: -0.5px;
    }

    .audience-grid {
        grid-template-columns: 1fr;
    }

    .promo-card {
        flex-direction: column;
        text-align: center;
        padding: 26px 22px;
    }

    .nav-links {
        gap: 0;
    }
}