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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Microsoft YaHei", sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #f8f8f8;
}

.container {
    max-width: 100%;
    margin: 0 auto;
    padding: 0 16px;
}

/* Header */
.header {
    background: #FF6B35;
    color: white;
    padding: 16px 0;
    box-shadow: 0 2px 8px rgba(255,107,53,0.2);
    position: sticky;
    top: 0;
    z-index: 100;
}

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

.logo h1 {
    font-size: 22px;
    font-weight: 600;
    margin-bottom: 2px;
}

.tagline {
    font-size: 12px;
    opacity: 0.9;
}

.nav {
    display: flex;
    gap: 8px;
}

.nav a {
    color: white;
    text-decoration: none;
    font-size: 13px;
    transition: background-color 0.3s;
    padding: 6px 10px;
    border-radius: 4px;
    white-space: nowrap;
}

.nav a:hover,
.nav a:active {
    background-color: rgba(255,255,255,0.2);
}

/* Hero Section */
.hero {
    background: white;
    padding: 30px 0;
    text-align: center;
    border-bottom: 1px solid #e5e7eb;
}

.hero h2 {
    font-size: 24px;
    color: #1f2937;
    margin-bottom: 10px;
}

.hero p {
    font-size: 14px;
    color: #6b7280;
}

/* Tutorial Sections */
.tutorial-section {
    padding: 30px 0;
    background: white;
}

.tutorial-section.alt {
    background: #f9fafb;
}

.section-header {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 20px;
}

.step-number {
    font-size: 32px;
    font-weight: 700;
    color: #FF6B35;
    opacity: 0.4;
}

.section-header h3 {
    font-size: 20px;
    color: #1f2937;
    font-weight: 600;
}

.tutorial-content {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

/* Video Wrapper */
.video-wrapper {
    position: relative;
    background: #000;
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 4px 12px rgba(0,0,0,0.15);
}

.video-placeholder {
    aspect-ratio: 16/9;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, #FF6B35 0%, #FF8C42 100%);
    cursor: pointer;
    transition: opacity 0.3s;
    -webkit-tap-highlight-color: transparent;
}

.video-placeholder:active {
    opacity: 0.9;
}

.video-placeholder p {
    color: white;
    margin-top: 12px;
    font-size: 14px;
}

/* Tutorial Steps */
.tutorial-steps {
    background: white;
    padding: 20px;
    border-radius: 8px;
    border: 1px solid #e5e7eb;
}

.tutorial-steps h4 {
    font-size: 16px;
    color: #1f2937;
    margin-bottom: 16px;
    padding-bottom: 8px;
    border-bottom: 2px solid #FF6B35;
    font-weight: 600;
}

.tutorial-steps ol {
    list-style: none;
    counter-reset: step-counter;
}

.tutorial-steps ol li {
    counter-increment: step-counter;
    margin-bottom: 20px;
    position: relative;
    padding-left: 36px;
}

.tutorial-steps ol li::before {
    content: counter(step-counter);
    position: absolute;
    left: 0;
    top: 0;
    width: 24px;
    height: 24px;
    background: #FF6B35;
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    font-size: 13px;
    flex-shrink: 0;
}

.tutorial-steps strong {
    display: block;
    color: #1f2937;
    margin-bottom: 6px;
    font-size: 15px;
}

.tutorial-steps p {
    color: #6b7280;
    line-height: 1.6;
    font-size: 14px;
}

.qr-code {
    margin-top: 12px;
}

.qr-placeholder {
    width: 120px;
    height: 120px;
    border: 2px dashed #d1d5db;
    display: flex;
    align-items: center;
    justify-content: center;
    color: #9ca3af;
    font-size: 12px;
    border-radius: 8px;
}

/* Tips */
.tips {
    margin-top: 20px;
    padding: 14px;
    background: #FFF5F0;
    border-left: 3px solid #FF6B35;
    border-radius: 6px;
}

.tips strong {
    color: #C44D2C;
    display: block;
    margin-bottom: 8px;
    font-size: 14px;
}

.tips p, .tips ul {
    color: #8B4513;
    font-size: 13px;
}

.tips ul {
    list-style: none;
    padding-left: 0;
}

.tips ul li {
    padding-left: 16px;
    position: relative;
    margin-bottom: 6px;
}

.tips ul li::before {
    content: "•";
    position: absolute;
    left: 4px;
    color: #FF6B35;
}

/* FAQ Section */
.faq-section {
    padding: 30px 0;
    background: white;
}

.faq-section h3 {
    font-size: 20px;
    color: #1f2937;
    text-align: center;
    margin-bottom: 20px;
    font-weight: 600;
}

.faq-list {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.faq-item {
    padding: 16px;
    background: #f9fafb;
    border-radius: 8px;
    border: 1px solid #e5e7eb;
    transition: background-color 0.3s;
}

.faq-item:active {
    background-color: #f3f4f6;
}

.faq-item h4 {
    color: #FF6B35;
    font-size: 15px;
    margin-bottom: 8px;
    font-weight: 600;
}

.faq-item p {
    color: #4b5563;
    line-height: 1.6;
    font-size: 14px;
}

/* Support Section */
.support-section {
    padding: 30px 0;
    background: linear-gradient(135deg, #FF6B35 0%, #FF8C42 100%);
    color: white;
    text-align: center;
}

.support-section h3 {
    font-size: 20px;
    margin-bottom: 10px;
    font-weight: 600;
}

.support-section > p {
    font-size: 14px;
    margin-bottom: 24px;
    opacity: 0.95;
}

.contact-info {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.contact-item {
    background: rgba(255,255,255,0.15);
    padding: 16px;
    border-radius: 8px;
    backdrop-filter: blur(10px);
    text-align: left;
}

.contact-item strong {
    display: block;
    font-size: 15px;
    margin-bottom: 8px;
}

.contact-item p {
    font-size: 16px;
    margin-bottom: 6px;
    font-weight: 500;
}

.contact-item span {
    font-size: 12px;
    opacity: 0.85;
}

/* Footer */
.footer {
    background: #1f2937;
    color: white;
    text-align: center;
    padding: 20px 0;
}

.footer p {
    opacity: 0.7;
    font-size: 13px;
}

/* 平板和桌面端适配 */
@media (min-width: 768px) {
    .container {
        max-width: 750px;
        padding: 0 24px;
    }
    
    .logo h1 {
        font-size: 26px;
    }
    
    .nav {
        gap: 20px;
    }
    
    .nav a {
        font-size: 15px;
        padding: 8px 14px;
    }
    
    .hero {
        padding: 50px 0;
    }
    
    .hero h2 {
        font-size: 32px;
    }
    
    .hero p {
        font-size: 16px;
    }
    
    .tutorial-section {
        padding: 50px 0;
    }
    
    .section-header h3 {
        font-size: 26px;
    }
    
    .step-number {
        font-size: 42px;
    }
    
    .tutorial-content {
        display: grid;
        grid-template-columns: 1fr 1fr;
        gap: 30px;
    }
    
    .tutorial-steps {
        padding: 24px;
    }
    
    .faq-section {
        padding: 50px 0;
    }
    
    .faq-section h3 {
        font-size: 28px;
        margin-bottom: 30px;
    }
    
    .faq-list {
        max-width: 800px;
        margin: 0 auto;
    }
    
    .support-section {
        padding: 50px 0;
    }
    
    .support-section h3 {
        font-size: 28px;
    }
    
    .support-section > p {
        font-size: 16px;
        margin-bottom: 40px;
    }
    
    .contact-info {
        flex-direction: row;
        gap: 24px;
    }
}

@media (min-width: 1024px) {
    .container {
        max-width: 1000px;
    }
}