/* ===================================
   KEVIN SOLO-OS Landing Page Styles
   Minimalist Black & White Design
   =================================== */

/* === CSS Reset & Base === */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    font-size: 16px;
    line-height: 1.6;
    color: #000000;
    background-color: #ffffff;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* === Typography === */
h1, h2, h3, h4, h5, h6 {
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: 16px;
}

h1 {
    font-size: 64px;
    letter-spacing: -2px;
}

h2 {
    font-size: 48px;
    letter-spacing: -1px;
}

h3 {
    font-size: 24px;
}

p {
    margin-bottom: 16px;
}

strong {
    font-weight: 700;
}

ul {
    list-style: none;
}

a {
    text-decoration: none;
    color: inherit;
}

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

section {
    padding: 80px 0;
}

/* === Section Labels === */
.section-label,
.hero-label {
    font-size: 12px;
    font-weight: 600;
    letter-spacing: 3px;
    text-transform: uppercase;
    margin-bottom: 24px;
    color: #666666;
}

.section-title {
    margin-bottom: 48px;
}

/* === Hero Section === */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    background-color: #ffffff;
    position: relative;
}

.hero-title {
    font-size: 96px;
    font-weight: 900;
    letter-spacing: -4px;
    line-height: 1;
    margin-bottom: 16px;
}

.hero-subtitle {
    font-size: 24px;
    font-weight: 400;
    margin-bottom: 16px;
    color: #333333;
}

.hero-tagline {
    font-size: 20px;
    font-weight: 600;
    margin-bottom: 48px;
    color: #000000;
}

/* === CTA Buttons === */
.cta-button {
    display: inline-block;
    padding: 16px 48px;
    font-size: 18px;
    font-weight: 600;
    color: #ffffff;
    background-color: #000000;
    border: 2px solid #000000;
    border-radius: 4px;
    cursor: pointer;
    transition: all 0.3s ease;
}

.cta-button:hover {
    background-color: #ffffff;
    color: #000000;
    transform: translateY(-2px);
}

.cta-button.large {
    padding: 20px 64px;
    font-size: 20px;
}

/* === Problem Section === */
.problem {
    background-color: #000000;
    color: #ffffff;
}

.problem .section-label {
    color: #999999;
}

.problem-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 48px;
}

.problem-item h3 {
    margin-bottom: 16px;
    font-size: 20px;
}

.problem-item p {
    color: #cccccc;
    line-height: 1.8;
}

/* === Solution Section === */
.solution {
    text-align: center;
    background-color: #f5f5f5;
}

.solution-description {
    font-size: 18px;
    line-height: 1.8;
    max-width: 800px;
    margin: 0 auto;
}

/* === Benefits Section === */
.benefits {
    background-color: #ffffff;
}

.benefits-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 48px;
}

.benefit-item {
    padding: 32px;
    border: 2px solid #000000;
    transition: all 0.3s ease;
}

.benefit-item:hover {
    background-color: #000000;
    color: #ffffff;
    transform: translateY(-4px);
}

.benefit-number {
    font-size: 48px;
    font-weight: 900;
    margin-bottom: 16px;
    letter-spacing: -2px;
}

.benefit-item h3 {
    margin-bottom: 16px;
}

.benefit-item p {
    line-height: 1.8;
    margin-bottom: 0;
}

/* === Preview Section === */
.preview {
    background-color: #f5f5f5;
}

.preview-content {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 32px;
    margin-bottom: 48px;
}

.preview-box {
    background-color: #ffffff;
    padding: 32px;
    border: 2px solid #e5e5e5;
}

.preview-box h3 {
    margin-bottom: 24px;
    font-size: 20px;
}

.preview-text ul {
    margin: 16px 0;
}

.preview-text li {
    padding: 8px 0;
    padding-left: 24px;
    position: relative;
    line-height: 1.8;
}

.preview-text li::before {
    content: "•";
    position: absolute;
    left: 0;
    font-weight: 700;
}

.preview-note {
    margin-top: 24px;
    padding: 16px;
    background-color: #f5f5f5;
    border-left: 4px solid #000000;
    font-weight: 600;
}

.preview .cta-button {
    display: block;
    max-width: 300px;
    margin: 0 auto;
    text-align: center;
}

/* === Pricing Section === */
.pricing {
    background-color: #ffffff;
    text-align: center;
}

.pricing-card {
    max-width: 600px;
    margin: 0 auto;
    padding: 48px;
    border: 3px solid #000000;
    background-color: #ffffff;
}

.price-tag {
    margin-bottom: 24px;
}

.price-amount {
    font-size: 72px;
    font-weight: 900;
    letter-spacing: -3px;
}

.price-period {
    font-size: 24px;
    color: #666666;
}

.pricing-card h3 {
    font-size: 28px;
    margin-bottom: 32px;
}

.pricing-features {
    text-align: left;
    margin: 32px 0;
}

.pricing-features li {
    padding: 12px 0;
    font-size: 18px;
    border-bottom: 1px solid #e5e5e5;
}

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

.pricing-note {
    font-size: 14px;
    color: #666666;
    margin: 24px 0;
}

/* === Final CTA Section === */
.final-cta {
    background-color: #000000;
    color: #ffffff;
    text-align: center;
}

.cta-title {
    color: #ffffff;
    margin-bottom: 24px;
}

.cta-description {
    font-size: 20px;
    margin-bottom: 48px;
    color: #cccccc;
}

.final-cta .cta-button {
    background-color: #ffffff;
    color: #000000;
    border-color: #ffffff;
}

.final-cta .cta-button:hover {
    background-color: #000000;
    color: #ffffff;
}

/* === Footer === */
.footer {
    background-color: #ffffff;
    text-align: center;
    padding: 48px 0;
    border-top: 1px solid #e5e5e5;
}

.footer p {
    margin-bottom: 8px;
    color: #666666;
}

.footer-tagline {
    font-weight: 600;
    color: #000000;
}

/* === Scroll Reveal Animations === */
/* 动画已禁用，确保截图时内容可见 */
.fade-in {
    opacity: 1;
    transform: translateY(0);
}

.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}

.hero {
    opacity: 1;
}

.hero.visible {
    opacity: 1;
}

/* === Responsive Design === */

/* Tablet (768px - 1024px) */
@media (max-width: 1024px) {
    h1 {
        font-size: 48px;
    }

    h2 {
        font-size: 36px;
    }

    .hero-title {
        font-size: 72px;
    }

    .problem-grid,
    .benefits-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 32px;
    }

    .preview-content {
        grid-template-columns: 1fr;
    }

    section {
        padding: 64px 0;
    }
}

/* Mobile (< 768px) */
@media (max-width: 768px) {
    .container {
        padding: 0 16px;
    }

    section {
        padding: 48px 0;
    }

    h1 {
        font-size: 36px;
    }

    h2 {
        font-size: 28px;
    }

    h3 {
        font-size: 20px;
    }

    .hero-title {
        font-size: 48px;
        letter-spacing: -2px;
    }

    .hero-subtitle {
        font-size: 18px;
    }

    .hero-tagline {
        font-size: 16px;
    }

    .problem-grid,
    .benefits-grid {
        grid-template-columns: 1fr;
        gap: 24px;
    }

    .benefit-item {
        padding: 24px;
    }

    .benefit-number {
        font-size: 36px;
    }

    .preview-content {
        grid-template-columns: 1fr;
        gap: 24px;
    }

    .preview-box {
        padding: 24px;
    }

    .pricing-card {
        padding: 32px 24px;
    }

    .price-amount {
        font-size: 56px;
    }

    .cta-button {
        padding: 14px 32px;
        font-size: 16px;
        width: 100%;
    }

    .cta-button.large {
        padding: 16px 40px;
        font-size: 18px;
    }

    .section-title {
        margin-bottom: 32px;
    }
}

/* === Scroll Indicator === */
.scroll-indicator {
    position: absolute;
    bottom: 40px;
    left: 50%;
    transform: translateX(-50%);
    text-align: center;
    cursor: pointer;
    z-index: 10;
    opacity: 0.7;
    transition: opacity 0.3s ease;
}

.scroll-indicator:hover {
    opacity: 1;
}

.scroll-arrow {
    font-size: 2.5rem;
    color: #000000;
    font-weight: 300;
    line-height: 1;
    animation: bounce 2s infinite;
    display: block;
}

.scroll-text {
    font-size: 0.875rem;
    color: #000000;
    margin-top: 8px;
    letter-spacing: 1px;
    font-weight: 400;
}

@keyframes bounce {
    0%, 20%, 50%, 80%, 100% {
        transform: translateY(0);
    }
    40% {
        transform: translateY(-10px);
    }
    60% {
        transform: translateY(-5px);
    }
}

/* Mobile responsive for scroll indicator */
@media (max-width: 768px) {
    .scroll-indicator {
        bottom: 30px;
    }

    .scroll-arrow {
        font-size: 2rem;
    }

    .scroll-text {
        font-size: 0.75rem;
    }
}