:root {
    /* Brand Handbook Colors */
    --c-bg: #FBFDFD;
    --c-surface: #FFFFFF;
    --c-border: #E6EEF0;
    --c-text: #102A2E;
    --c-text-muted: #5B6B6E;
    --c-accent: #22C1C3;
    --c-accent-soft: #D6F6F6;
    --c-danger: #E55D5D;
    --c-warning: #D39B2A;

    /* Spacing */
    --spacing-unit: 4px;
    --container-width: 1200px;
    --header-height: 80px;

    /* Typography */
    --font-main: "Source Han Sans SC", "Noto Sans SC", "Microsoft YaHei", system-ui, sans-serif;
    --font-display: "Source Sans 3", "Inter", system-ui, sans-serif;

    /* Radius */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 24px;
    --radius-full: 9999px;

    /* Shadows (Airy) */
    --shadow-sm: 0 1px 2px rgba(16, 42, 46, 0.04);
    --shadow-md: 0 4px 12px rgba(16, 42, 46, 0.06);
    --shadow-lg: 0 12px 32px rgba(16, 42, 46, 0.08);
    --shadow-glow: 0 0 20px rgba(34, 193, 195, 0.15);

    /* Transitions */
    --ease-spring: cubic-bezier(0.2, 0.8, 0.2, 1);
    --ease-smooth: cubic-bezier(0.4, 0, 0.2, 1);
}

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

body {
    font-family: var(--font-main);
    background-color: var(--c-bg);
    color: var(--c-text);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    overflow-x: hidden;
    width: 100%;
}

/* Typography */
h1,
h2,
h3,
h4,
h5,
h6 {
    font-family: var(--font-display);
    font-weight: 600;
    line-height: 1.2;
    color: var(--c-text);
}

h1 {
    font-size: 3.5rem;
    letter-spacing: -0.02em;
}

h2 {
    font-size: 2.5rem;
    letter-spacing: -0.01em;
}

h3 {
    font-size: 1.5rem;
}

p {
    color: var(--c-text-muted);
}

a {
    text-decoration: none;
    color: inherit;
    transition: all 0.2s var(--ease-smooth);
}

/* Layout */
.container {
    max-width: var(--container-width);
    width: 100%;
    margin: 0 auto;
    padding: 0 24px;
}

section {
    padding: 80px 0;
}

/* Header */
header {
    height: var(--header-height);
    display: flex;
    align-items: center;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background: rgba(251, 253, 253, 0.85);
    backdrop-filter: blur(12px);
    z-index: 100;
    border-bottom: 1px solid transparent;
    transition: border-color 0.3s;
}

header.scrolled {
    border-bottom-color: var(--c-border);
}

header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    width: 100%;
}

.logo {
    display: flex;
    align-items: center;
    gap: 12px;
    font-weight: 700;
    font-size: 1.25rem;
    color: var(--c-text);
}

.logo img {
    width: 32px;
    height: 32px;
}

.nav-links {
    display: flex;
    align-items: center;
    gap: 32px;
}

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

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 12px 24px;
    border-radius: var(--radius-sm);
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s var(--ease-spring);
    font-size: 1rem;
}

.btn-primary {
    background-color: var(--c-accent);
    color: white;
    box-shadow: 0 4px 12px rgba(34, 193, 195, 0.3);
}

.btn-primary:hover {
    background-color: #1EB0B2;
    transform: translateY(-2px);
    box-shadow: 0 8px 20px rgba(34, 193, 195, 0.4);
}

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

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

/* Hero Section */
.hero {
    padding-top: calc(var(--header-height) + 60px);
    padding-bottom: 100px;
}

.hero .container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    align-items: center;
    gap: 60px;
}

.hero-content {
    max-width: 500px;
}

.hero h1 {
    margin-bottom: 24px;
    background: linear-gradient(135deg, var(--c-text) 0%, #2C5F66 100%);
    background-clip: text;
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero p {
    font-size: 1.25rem;
    margin-bottom: 40px;
    line-height: 1.6;
}

.hero-buttons {
    display: flex;
    gap: 16px;
}

.hero-image {
    position: relative;
}

.hero-image img {
    width: 100%;
    height: auto;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    animation: float 6s ease-in-out infinite;
}

@keyframes float {
    0% {
        transform: translateY(0px) rotate(0deg);
    }

    50% {
        transform: translateY(-20px) rotate(0.5deg);
    }

    100% {
        transform: translateY(0px) rotate(0deg);
    }
}

/* Features Grid */
.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 32px;
}

.feature-card {
    background: var(--c-surface);
    padding: 32px;
    border-radius: var(--radius-md);
    border: 1px solid var(--c-border);
    transition: all 0.2s var(--ease-spring);
}

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

.feature-icon {
    width: 48px;
    height: 48px;
    background: var(--c-accent-soft);
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 24px;
    color: var(--c-accent);
}

.feature-card h3 {
    margin-bottom: 12px;
    font-size: 1.25rem;
}

.feature-card p {
    font-size: 0.95rem;
}

/* Persona Section */
.persona-section {
    background: linear-gradient(180deg, var(--c-bg) 0%, var(--c-accent-soft) 100%);
    border-radius: var(--radius-lg);
    margin: 80px 0;
    overflow: hidden;
}

.persona-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    align-items: center;
    gap: 40px;
    padding: 0;
}

.persona-text {
    padding: 60px;
}

.persona-text blockquote {
    font-size: 1.5rem;
    font-weight: 500;
    color: var(--c-text);
    margin-bottom: 24px;
    border-left: 4px solid var(--c-accent);
    padding-left: 24px;
}

.persona-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
}

/* Footer */
footer {
    border-top: 1px solid var(--c-border);
    padding: 60px 0;
    text-align: center;
    background: var(--c-surface);
}

.download-cta {
    margin-bottom: 40px;
}

.download-cta h2 {
    font-size: 2rem;
    margin-bottom: 24px;
}

.footer-links {
    display: flex;
    justify-content: center;
    gap: 24px;
    color: var(--c-text-muted);
    font-size: 0.9rem;
}

/* Responsive */
@media (max-width: 1024px) {
    .hero {
        grid-template-columns: 1fr;
        text-align: center;
        gap: 40px;
    }

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

    .persona-container {
        grid-template-columns: 1fr;
    }

    .persona-image {
        order: -1;
    }

    h1 {
        font-size: 2.5rem;
    }
}

/* Showcase Section */
.showcase-section {
    background-color: var(--c-surface);
    overflow: hidden;
}

.showcase-container {
    display: flex;
    flex-direction: column;
    gap: 120px;
}

.showcase-item {
    display: grid;
    grid-template-columns: 1fr 1fr;
    align-items: center;
    gap: 80px;
}

.showcase-item.reverse {
    direction: rtl;
}

.showcase-item.reverse .showcase-text {
    direction: ltr;
}

.showcase-text {
    max-width: 480px;
}

.showcase-text h2 {
    font-size: 2.25rem;
    margin-bottom: 24px;
    color: var(--c-text);
}

.showcase-text p {
    font-size: 1.125rem;
    margin-bottom: 32px;
}

.screenshot-frame {
    position: relative;
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-lg);
    border: 1px solid var(--c-border);
    overflow: hidden;
    transition: transform 0.4s var(--ease-spring);
    background: var(--c-bg);
}

.screenshot-frame:hover {
    transform: translateY(-8px);
    box-shadow: 0 20px 40px rgba(16, 42, 46, 0.12);
}

.screenshot-frame img {
    width: 100%;
    height: auto;
    display: block;
}

.screenshot-caption {
    position: absolute;
    bottom: 20px;
    left: 50%;
    transform: translateX(-50%);
    background: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(8px);
    padding: 8px 16px;
    border-radius: var(--radius-full);
    font-size: 0.875rem;
    color: var(--c-text-muted);
    border: 1px solid white;
    box-shadow: var(--shadow-sm);
    white-space: nowrap;
    opacity: 0;
    transition: opacity 0.3s ease;
}

.screenshot-frame:hover .screenshot-caption {
    opacity: 1;
}

/* Philosophy Section */
.philosophy-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 40px;
    margin-top: 60px;
}

.philosophy-item {
    background: white;
    padding: 40px;
    border-radius: var(--radius-md);
    border: 1px solid var(--c-border);
}

.philosophy-item h3 {
    color: var(--c-accent);
    margin-bottom: 16px;
    font-size: 1.5rem;
}

@media (max-width: 1024px) {

    .showcase-item,
    .showcase-item.reverse {
        grid-template-columns: 1fr;
        gap: 40px;
        direction: ltr;
        text-align: center;
    }

    .showcase-text {
        max-width: 100%;
        margin: 0 auto;
    }

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