/* ==========================================
   ReelSpeak Landing Page — Apple Design Language
   ========================================== */

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "SF Pro Display", "SF Pro Text",
        "Helvetica Neue", "PingFang SC", sans-serif;
    background: #000;
    color: #f5f5f7;
    -webkit-font-smoothing: antialiased;
    overflow-x: hidden;
}

/* ==========================================
   导航
   ========================================== */
.nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(0, 0, 0, 0.72);
    backdrop-filter: saturate(180%) blur(20px);
    -webkit-backdrop-filter: saturate(180%) blur(20px);
    border-bottom: 0.5px solid rgba(255, 255, 255, 0.08);
}

.nav-inner {
    max-width: 1024px;
    margin: 0 auto;
    padding: 0 22px;
    height: 48px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.nav-logo {
    font-size: 21px;
    font-weight: 700;
    color: #f5f5f7;
    text-decoration: none;
    letter-spacing: -0.02em;
}

.nav-cta {
    font-size: 13px;
    color: #fff;
    background: #0071e3;
    padding: 6px 16px;
    border-radius: 980px;
    text-decoration: none;
    transition: background 0.2s;
}

.nav-right {
    display: flex;
    align-items: center;
    gap: 12px;
}

.lang-switcher {
    display: flex;
    gap: 2px;
}

.lang-switcher-select {
    background: rgba(255,255,255,0.08);
    color: #ccc;
    border: 1px solid rgba(255,255,255,0.15);
    padding: 5px 8px;
    font-size: 12px;
    cursor: pointer;
    border-radius: 6px;
}

.nav-cta:hover {
    background: #0077ed;
}

/* ==========================================
   通用
   ========================================== */
.section-inner {
    max-width: 980px;
    margin: 0 auto;
    padding: 0 22px;
}

.section-title {
    font-size: 48px;
    font-weight: 700;
    letter-spacing: -0.03em;
    text-align: center;
    margin-bottom: 12px;
}

.section-desc {
    font-size: 21px;
    color: #86868b;
    text-align: center;
    margin-bottom: 64px;
    font-weight: 400;
}

.gradient-text {
    background: linear-gradient(135deg, #e94560, #ff6b9d, #c44dff);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* 滚动动画 */
.feature-card,
.step-item,
.highlight-row,
.cta {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.8s ease, transform 0.8s ease;
}

.feature-card.visible,
.step-item.visible,
.highlight-row.visible,
.cta.visible {
    opacity: 1;
    transform: translateY(0);
}

.feature-card:nth-child(2) { transition-delay: 0.1s; }
.feature-card:nth-child(3) { transition-delay: 0.2s; }
.step-item:nth-child(2) { transition-delay: 0.15s; }
.step-item:nth-child(3) { transition-delay: 0.3s; }

/* ==========================================
   按钮
   ========================================== */
.btn-primary {
    display: inline-block;
    font-size: 17px;
    font-weight: 500;
    color: #fff;
    background: #0071e3;
    padding: 12px 28px;
    border-radius: 980px;
    text-decoration: none;
    transition: background 0.2s;
}

.btn-primary:hover {
    background: #0077ed;
}

.btn-primary.btn-large {
    font-size: 19px;
    padding: 16px 36px;
}

.btn-secondary {
    display: inline-block;
    font-size: 17px;
    font-weight: 500;
    color: #2997ff;
    text-decoration: none;
    padding: 12px 28px;
    transition: color 0.2s;
}

.btn-secondary:hover {
    color: #6cb7ff;
}

/* ==========================================
   Hero
   ========================================== */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 100px 22px 80px;
    gap: 60px;
    max-width: 1200px;
    margin: 0 auto;
}

.hero-content {
    flex: 1;
    max-width: 560px;
}

.hero-title {
    font-size: 64px;
    font-weight: 700;
    line-height: 1.08;
    letter-spacing: -0.04em;
    margin-bottom: 24px;
}

.hero-line {
    display: block;
}

.hero-subtitle {
    font-size: 21px;
    line-height: 1.5;
    color: #86868b;
    margin-bottom: 36px;
    font-weight: 400;
}

.hero-actions {
    display: flex;
    gap: 12px;
    align-items: center;
}

/* 手机模型 */
.hero-visual {
    flex-shrink: 0;
}

.phone-mockup {
    width: 280px;
    height: 560px;
    background: #1d1d1f;
    border-radius: 40px;
    padding: 12px;
    box-shadow:
        0 0 0 1px rgba(255, 255, 255, 0.06),
        0 40px 80px rgba(0, 0, 0, 0.5);
    position: relative;
}

.phone-screen {
    width: 100%;
    height: 100%;
    background: linear-gradient(180deg, #1a1a2e 0%, #16213e 100%);
    border-radius: 30px;
    overflow: hidden;
    display: flex;
    flex-direction: column;
    position: relative;
}

.mock-video {
    flex: 1;
    background:
        linear-gradient(135deg, rgba(233, 69, 96, 0.15), rgba(196, 77, 255, 0.1)),
        linear-gradient(180deg, #0d0d1a, #16213e);
    display: flex;
    align-items: center;
    justify-content: center;
}

.mock-subtitle {
    padding: 16px 20px;
    text-align: center;
}

.mock-thai {
    font-size: 16px;
    color: #ffd700;
    margin-bottom: 6px;
    font-weight: 500;
}

.mock-cn {
    font-size: 13px;
    color: rgba(255, 255, 255, 0.7);
}

.mock-score {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    display: flex;
    flex-direction: column;
    align-items: center;
    background: rgba(0, 0, 0, 0.6);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    padding: 20px 30px;
    border-radius: 20px;
    border: 0.5px solid rgba(255, 255, 255, 0.1);
}

.mock-score-num {
    font-size: 48px;
    font-weight: 700;
    color: #30d158;
    line-height: 1;
}

.mock-score-label {
    font-size: 13px;
    color: #86868b;
    margin-top: 4px;
}

/* ==========================================
   功能卡片
   ========================================== */
.features {
    padding: 120px 0;
    background: #000;
}

.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 20px;
}

.feature-card {
    background: #1d1d1f;
    border-radius: 20px;
    padding: 40px 32px;
    transition: opacity 0.8s ease, transform 0.8s ease;
}

.feature-icon {
    width: 48px;
    height: 48px;
    color: #e94560;
    margin-bottom: 20px;
}

.feature-icon svg {
    width: 100%;
    height: 100%;
}

.feature-card h3 {
    font-size: 24px;
    font-weight: 700;
    margin-bottom: 10px;
    letter-spacing: -0.02em;
}

.feature-card p {
    font-size: 15px;
    line-height: 1.6;
    color: #86868b;
}

/* ==========================================
   使用流程
   ========================================== */
.how-it-works {
    padding: 120px 0;
    background: #000;
}

.steps {
    max-width: 640px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: 32px;
}

.step-item {
    display: flex;
    align-items: flex-start;
    gap: 24px;
    padding: 32px;
    background: #1d1d1f;
    border-radius: 20px;
}

.step-num {
    width: 48px;
    height: 48px;
    background: linear-gradient(135deg, #e94560, #c44dff);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 20px;
    font-weight: 700;
    flex-shrink: 0;
}

.step-content h3 {
    font-size: 21px;
    font-weight: 700;
    margin-bottom: 6px;
    letter-spacing: -0.02em;
}

.step-content p {
    font-size: 15px;
    line-height: 1.6;
    color: #86868b;
}

/* ==========================================
   功能亮点
   ========================================== */
.highlights {
    padding: 120px 0;
    background: #000;
}

.highlight-row {
    display: flex;
    align-items: center;
    gap: 80px;
    margin-bottom: 120px;
}

.highlight-row:last-child {
    margin-bottom: 0;
}

.highlight-row.reverse {
    flex-direction: row-reverse;
}

.highlight-text {
    flex: 1;
}

.highlight-text h2 {
    font-size: 40px;
    font-weight: 700;
    line-height: 1.15;
    letter-spacing: -0.03em;
    margin-bottom: 16px;
}

.highlight-text p {
    font-size: 17px;
    line-height: 1.6;
    color: #86868b;
}

.highlight-visual {
    flex: 1;
    display: flex;
    justify-content: center;
}

.glass-card {
    background: rgba(255, 255, 255, 0.04);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: 0.5px solid rgba(255, 255, 255, 0.08);
    border-radius: 20px;
    padding: 32px;
    width: 100%;
    max-width: 360px;
}

/* 双引擎卡片 */
.engine-row {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 8px;
}

.engine-tag {
    font-size: 13px;
    font-weight: 600;
    padding: 6px 14px;
    border-radius: 980px;
}

.engine-tag.groq {
    background: rgba(255, 149, 0, 0.15);
    color: #ff9500;
    border: 0.5px solid rgba(255, 149, 0, 0.3);
}

.engine-tag.azure {
    background: rgba(0, 113, 227, 0.15);
    color: #0071e3;
    border: 0.5px solid rgba(0, 113, 227, 0.3);
}

.engine-tag.combined {
    background: rgba(48, 209, 88, 0.15);
    color: #30d158;
    border: 0.5px solid rgba(48, 209, 88, 0.3);
}

.engine-desc {
    font-size: 14px;
    color: #86868b;
}

.engine-plus {
    text-align: center;
    font-size: 18px;
    color: #48484a;
    margin: 8px 0;
}

.engine-result {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-top: 8px;
    padding-top: 16px;
    border-top: 0.5px solid rgba(255, 255, 255, 0.06);
}

.engine-arrow {
    color: #48484a;
    font-size: 16px;
}

/* 三遍学习法卡片 */
.pass-item {
    display: flex;
    align-items: center;
    gap: 14px;
    padding: 14px 16px;
    border-radius: 12px;
    margin-bottom: 8px;
    background: rgba(255, 255, 255, 0.02);
    border: 0.5px solid rgba(255, 255, 255, 0.04);
    transition: all 0.3s;
}

.pass-item:last-child {
    margin-bottom: 0;
}

.pass-item.active {
    background: rgba(233, 69, 96, 0.08);
    border-color: rgba(233, 69, 96, 0.2);
}

.pass-num {
    width: 32px;
    height: 32px;
    border-radius: 50%;
    background: #2c2c2e;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 14px;
    font-weight: 700;
    flex-shrink: 0;
}

.pass-item.active .pass-num {
    background: linear-gradient(135deg, #e94560, #c44dff);
}

.pass-label {
    font-size: 15px;
    font-weight: 600;
    width: 40px;
    flex-shrink: 0;
}

.pass-desc {
    font-size: 14px;
    color: #86868b;
    line-height: 1.4;
}

.pass-desc small {
    color: #fff;
    font-size: 12px;
}

/* ==========================================
   CTA
   ========================================== */
.cta {
    padding: 120px 0;
    text-align: center;
    background: #000;
}

.cta-title {
    font-size: 56px;
    font-weight: 700;
    letter-spacing: -0.04em;
    margin-bottom: 16px;
}

.cta-desc {
    font-size: 21px;
    color: #86868b;
    margin-bottom: 32px;
}

/* ==========================================
   Footer
   ========================================== */
.footer {
    padding: 20px 0;
    border-top: 0.5px solid rgba(255, 255, 255, 0.06);
    background: #000;
}

.footer-inner {
    max-width: 980px;
    margin: 0 auto;
    padding: 0 22px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.footer-logo {
    font-size: 15px;
    font-weight: 700;
    color: #f5f5f7;
}

.footer-copy {
    font-size: 13px;
    color: #48484a;
}

/* ==========================================
   响应式
   ========================================== */
@media (max-width: 1024px) {
    .hero {
        flex-direction: column;
        text-align: center;
        padding-top: 120px;
        gap: 48px;
    }

    .hero-actions {
        justify-content: center;
    }

    .highlight-row,
    .highlight-row.reverse {
        flex-direction: column;
        gap: 40px;
        text-align: center;
    }
}

@media (max-width: 768px) {
    .hero-title {
        font-size: 44px;
    }

    .hero-subtitle {
        font-size: 17px;
    }

    .section-title {
        font-size: 36px;
    }

    .section-desc {
        font-size: 17px;
        margin-bottom: 40px;
    }

    .feature-grid {
        grid-template-columns: 1fr;
        gap: 16px;
    }

    .feature-card {
        padding: 28px 24px;
    }

    .phone-mockup {
        width: 240px;
        height: 480px;
    }

    .highlight-text h2 {
        font-size: 32px;
    }

    .cta-title {
        font-size: 36px;
    }

    .features,
    .how-it-works,
    .highlights,
    .cta {
        padding: 80px 0;
    }

    .highlight-row {
        margin-bottom: 80px;
    }

    .step-item {
        padding: 24px;
    }
}

@media (max-width: 480px) {
    .hero-title {
        font-size: 36px;
    }

    .section-title {
        font-size: 28px;
    }

    .hero-actions {
        flex-direction: column;
        gap: 8px;
    }

    .cta-title {
        font-size: 28px;
    }
}