/* ====== WriteFlow AI写作平台样式 ====== */
/* 风格：清新科技风，青蓝色调，明亮干净 */

* { margin: 0; padding: 0; box-sizing: border-box; }

:root {
    --bg: #f8fafc;
    --bg-card: #ffffff;
    --bg-card-hover: #f0f9ff;
    --text: #0f172a;
    --text-muted: #64748b;
    --accent: #06b6d4;
    --accent2: #3b82f6;
    --accent3: #0ea5e9;
    --gradient: linear-gradient(135deg, #06b6d4 0%, #3b82f6 100%);
    --gradient-soft: linear-gradient(135deg, rgba(6, 182, 212, 0.08) 0%, rgba(59, 130, 246, 0.08) 100%);
    --border: #e2e8f0;
    --border-accent: rgba(6, 182, 212, 0.3);
    --radius: 16px;
    --radius-sm: 10px;
    --shadow: 0 1px 3px rgba(0,0,0,0.06), 0 1px 2px rgba(0,0,0,0.04);
    --shadow-lg: 0 10px 40px rgba(6, 182, 212, 0.1), 0 2px 8px rgba(0,0,0,0.04);
}

html { scroll-behavior: smooth; }

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
    overflow-x: hidden;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

/* ====== 导航栏 ====== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    padding: 14px 0;
    background: rgba(255, 255, 255, 0.88);
    backdrop-filter: blur(16px) saturate(1.8);
    border-bottom: 1px solid var(--border);
    transition: all 0.3s;
}

.navbar.scrolled {
    box-shadow: 0 1px 12px rgba(0,0,0,0.06);
}

.nav-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.logo {
    display: flex;
    align-items: center;
    gap: 8px;
    text-decoration: none;
    color: var(--text);
    font-weight: 800;
    font-size: 1.4rem;
}

.logo-icon {
    background: var(--gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    font-size: 1.6rem;
}

.nav-links {
    display: flex;
    align-items: center;
    gap: 32px;
    list-style: none;
}

.nav-links a {
    color: var(--text-muted);
    text-decoration: none;
    font-size: 0.9rem;
    font-weight: 500;
    transition: color 0.2s;
}

.nav-links a:hover { color: var(--text); }

.btn-nav {
    background: var(--gradient) !important;
    -webkit-background-clip: text !important;
    -webkit-text-fill-color: transparent !important;
}

.mobile-menu-btn {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 4px;
}

.mobile-menu-btn span {
    display: block;
    width: 24px;
    height: 2px;
    background: var(--text);
    transition: all 0.3s;
}

/* ====== 按钮 ====== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 13px 30px;
    border-radius: 12px;
    font-size: 0.95rem;
    font-weight: 600;
    text-decoration: none;
    transition: all 0.25s;
    cursor: pointer;
    border: none;
}

.btn-primary {
    background: var(--gradient);
    color: #fff;
    box-shadow: 0 4px 16px rgba(6, 182, 212, 0.25);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 28px rgba(6, 182, 212, 0.35);
}

.btn-secondary {
    background: transparent;
    color: var(--text);
    border: 1px solid var(--border);
}

.btn-secondary:hover {
    border-color: var(--accent);
    color: var(--accent);
    background: var(--gradient-soft);
}

.btn-outline {
    background: transparent;
    color: var(--text);
    border: 1px solid var(--border);
    border-radius: 12px;
}

.btn-outline:hover {
    border-color: var(--accent);
    color: var(--accent);
    background: var(--gradient-soft);
}

.btn-full { width: 100%; }

/* ====== Hero ====== */
.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding: 120px 0 80px;
    overflow: hidden;
    background: linear-gradient(180deg, #f0f9ff 0%, var(--bg) 100%);
}

.hero-bg {
    position: absolute;
    inset: 0;
    overflow: hidden;
}

.gradient-orb {
    position: absolute;
    border-radius: 50%;
    filter: blur(100px);
    opacity: 0.25;
    animation: float 8s ease-in-out infinite;
}

.orb-1 {
    width: 500px;
    height: 500px;
    background: #22d3ee;
    top: -180px;
    right: -80px;
}

.orb-2 {
    width: 400px;
    height: 400px;
    background: #3b82f6;
    bottom: -120px;
    left: -80px;
    animation-delay: -4s;
}

@keyframes float {
    0%, 100% { transform: translateY(0) scale(1); }
    50% { transform: translateY(-25px) scale(1.04); }
}

.hero-content {
    position: relative;
    z-index: 1;
    text-align: center;
}

.hero-badge {
    display: inline-block;
    padding: 8px 22px;
    background: rgba(6, 182, 212, 0.08);
    border: 1px solid rgba(6, 182, 212, 0.2);
    border-radius: 12px;
    font-size: 0.85rem;
    color: var(--accent);
    margin-bottom: 24px;
    font-weight: 500;
}

.hero-title {
    font-size: clamp(2.5rem, 6vw, 4.5rem);
    font-weight: 900;
    line-height: 1.1;
    margin-bottom: 24px;
    letter-spacing: -0.02em;
    color: var(--text);
}

.gradient-text {
    background: var(--gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero-desc {
    font-size: 1.1rem;
    color: var(--text-muted);
    max-width: 600px;
    margin: 0 auto 32px;
    line-height: 1.8;
}

.hero-buttons {
    display: flex;
    gap: 16px;
    justify-content: center;
    flex-wrap: wrap;
    margin-bottom: 48px;
}

/* ====== Demo 窗口 ====== */
.hero-demo {
    max-width: 700px;
    margin: 0 auto;
}

.demo-window {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    overflow: hidden;
    box-shadow: var(--shadow-lg);
}

.demo-header {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 14px 20px;
    border-bottom: 1px solid var(--border);
    background: #fafbfc;
}

.demo-dot {
    width: 12px;
    height: 12px;
    border-radius: 50%;
}

.demo-title {
    font-size: 0.8rem;
    color: var(--text-muted);
    margin-left: 8px;
}

.demo-body {
    padding: 24px;
}

.demo-input, .demo-output {
    margin-bottom: 20px;
}

.demo-user, .demo-ai {
    display: inline-block;
    font-size: 0.8rem;
    font-weight: 700;
    margin-bottom: 6px;
}

.demo-user { color: var(--accent); }
.demo-ai { color: #10b981; }

.demo-input p, .demo-output p {
    font-size: 0.95rem;
    line-height: 1.7;
    color: var(--text);
}

.typing-text {
    color: var(--text);
    border-right: 2px solid var(--accent);
    animation: blink 0.8s step-end infinite;
    white-space: normal;
}

@keyframes blink {
    50% { border-color: transparent; }
}

/* ====== Section ====== */
.section { padding: 100px 0; }
.section-dark {
    background: #ffffff;
    border-top: 1px solid var(--border);
    border-bottom: 1px solid var(--border);
}

.section-header {
    text-align: center;
    margin-bottom: 64px;
}

.section-tag {
    display: inline-block;
    padding: 6px 16px;
    background: rgba(6, 182, 212, 0.08);
    border: 1px solid rgba(6, 182, 212, 0.2);
    border-radius: 12px;
    font-size: 0.8rem;
    color: var(--accent);
    margin-bottom: 16px;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    font-weight: 600;
}

.section-title {
    font-size: clamp(2rem, 4vw, 3rem);
    font-weight: 800;
    margin-bottom: 16px;
    letter-spacing: -0.02em;
    color: var(--text);
}

.section-desc {
    color: var(--text-muted);
    font-size: 1.05rem;
}

/* ====== 功能卡片 ====== */
.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 20px;
}

.feature-card {
    padding: 32px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    transition: all 0.3s;
    box-shadow: var(--shadow);
}

.feature-card:hover {
    border-color: var(--accent);
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.feature-icon {
    font-size: 2.5rem;
    margin-bottom: 20px;
}

.feature-card h3 {
    font-size: 1.2rem;
    font-weight: 700;
    margin-bottom: 12px;
    color: var(--text);
}

.feature-card p {
    color: var(--text-muted);
    font-size: 0.9rem;
    line-height: 1.7;
}

/* ====== 场景卡片 ====== */
.scenarios-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 20px;
}

.scenario-card {
    padding: 32px;
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    transition: all 0.3s;
}

.scenario-card:hover {
    border-color: var(--accent);
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.scenario-num {
    font-size: 2.5rem;
    font-weight: 900;
    background: var(--gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 16px;
}

.scenario-card h3 {
    font-size: 1.15rem;
    font-weight: 700;
    margin-bottom: 12px;
    color: var(--text);
}

.scenario-card p {
    color: var(--text-muted);
    font-size: 0.9rem;
    line-height: 1.7;
    margin-bottom: 16px;
}

.scenario-tags {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
}

.scenario-tags span {
    padding: 4px 12px;
    background: rgba(6, 182, 212, 0.08);
    border: 1px solid rgba(6, 182, 212, 0.15);
    border-radius: 8px;
    font-size: 0.75rem;
    color: var(--accent);
    font-weight: 500;
}

/* ====== 定价 ====== */
.pricing-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 20px;
    align-items: start;
}

.pricing-card {
    padding: 36px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    position: relative;
    transition: all 0.3s;
    box-shadow: var(--shadow);
}

.pricing-card.featured {
    border-color: var(--accent);
    background: var(--gradient-soft);
    transform: scale(1.05);
    box-shadow: var(--shadow-lg);
}

.pricing-badge {
    position: absolute;
    top: -12px;
    left: 50%;
    transform: translateX(-50%);
    padding: 4px 16px;
    background: var(--gradient);
    border-radius: 8px;
    font-size: 0.75rem;
    font-weight: 700;
    color: #fff;
    white-space: nowrap;
}

.pricing-header {
    text-align: center;
    margin-bottom: 28px;
}

.pricing-header h3 {
    font-size: 1.2rem;
    font-weight: 700;
    margin-bottom: 12px;
    color: var(--text);
}

.pricing-price {
    display: flex;
    align-items: baseline;
    justify-content: center;
    gap: 4px;
}

.price {
    font-size: 3rem;
    font-weight: 900;
    color: var(--text);
}

.period {
    color: var(--text-muted);
    font-size: 0.9rem;
}

.pricing-features {
    list-style: none;
    margin-bottom: 28px;
}

.pricing-features li {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 10px 0;
    font-size: 0.9rem;
    border-bottom: 1px solid var(--border);
    color: var(--text);
}

.pricing-features li:last-child { border-bottom: none; }

.pricing-features .check {
    font-weight: 700;
    width: 20px;
    text-align: center;
    color: var(--accent);
}

.pricing-features .disabled {
    color: var(--text-muted);
}

.pricing-features .disabled .check {
    color: #cbd5e1;
}

/* ====== FAQ ====== */
.faq-list {
    max-width: 700px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.faq-item {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    overflow: hidden;
    box-shadow: var(--shadow);
}

.faq-question {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 24px;
    cursor: pointer;
    font-weight: 600;
    font-size: 0.95rem;
    transition: all 0.2s;
    color: var(--text);
}

.faq-question:hover { color: var(--accent); }

.faq-arrow {
    font-size: 1.2rem;
    transition: transform 0.3s;
    color: var(--text-muted);
}

.faq-item.active .faq-arrow { transform: rotate(90deg); }

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease;
}

.faq-item.active .faq-answer { max-height: 200px; }

.faq-answer p {
    padding: 0 24px 20px;
    color: var(--text-muted);
    font-size: 0.9rem;
    line-height: 1.7;
}

/* ====== CTA ====== */
.cta-section { padding: 80px 0; }

.cta-card {
    text-align: center;
    padding: 64px;
    background: var(--gradient-soft);
    border: 1px solid var(--border-accent);
    border-radius: var(--radius);
}

.cta-card h2 {
    font-size: 2rem;
    font-weight: 800;
    margin-bottom: 12px;
    color: var(--text);
}

.cta-card p {
    color: var(--text-muted);
    margin-bottom: 24px;
}

.register-form {
    display: flex;
    gap: 12px;
    max-width: 500px;
    margin: 0 auto 16px;
}

.register-form input {
    flex: 1;
    padding: 14px 18px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 12px;
    color: var(--text);
    font-size: 0.95rem;
    outline: none;
    box-shadow: var(--shadow);
}

.register-form input:focus { border-color: var(--accent); }

.cta-note {
    font-size: 0.85rem;
    color: var(--text-muted);
}

.cta-note a {
    color: var(--accent);
    text-decoration: none;
    font-weight: 500;
}

/* ====== 页脚 ====== */
.footer {
    padding: 64px 0 32px;
    border-top: 1px solid var(--border);
    background: #ffffff;
}

.footer-grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: 48px;
    margin-bottom: 48px;
}

.footer-brand p {
    color: var(--text-muted);
    margin-top: 12px;
    font-size: 0.9rem;
}

.footer-links {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.footer-links h4 {
    font-size: 0.9rem;
    font-weight: 700;
    margin-bottom: 4px;
    color: var(--text);
}

.footer-links a {
    color: var(--text-muted);
    text-decoration: none;
    font-size: 0.85rem;
    transition: color 0.2s;
}

.footer-links a:hover { color: var(--accent); }

.footer-bottom {
    text-align: center;
    padding-top: 32px;
    border-top: 1px solid var(--border);
}

.footer-bottom p {
    color: var(--text-muted);
    font-size: 0.8rem;
}

/* ====== 响应式 ====== */
@media (max-width: 768px) {
    .nav-links { display: none; }
    .mobile-menu-btn { display: flex; }
    .nav-links.active {
        display: flex;
        flex-direction: column;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: var(--bg-card);
        padding: 24px;
        border-bottom: 1px solid var(--border);
        box-shadow: 0 8px 24px rgba(0,0,0,0.06);
    }
    .features-grid { grid-template-columns: 1fr; }
    .pricing-card.featured { transform: scale(1); }
    .register-form { flex-direction: column; }
    .footer-grid { grid-template-columns: 1fr 1fr; }
    .cta-card { padding: 40px 24px; }
}