/* 
 * GUYUANDAI Brand Website - Global Styles
 * Theme: Oriental Ink / Minimalist / Zen
 */

:root {
    /* Color Palette */
    --bg-color: #FAFAF8;       /* Rice Paper White */
    --text-main: #1A1A1A;      /* Ink Black */
    --text-secondary: #5A5A5A; /* Charcoal Gray */
    --accent-color: #6B7B6E;   /* Mountain Green/Grey */
    --border-color: #E0E0E0;
    
    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 2rem;
    --spacing-lg: 4rem;
    --spacing-xl: 8rem;
    
    /* Typography */
    --font-main: "Noto Serif SC", "Songti SC", serif;
    --font-eng: "Cormorant Garamond", serif;
}

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

html {
    scroll-behavior: smooth;
}

body {
    background-color: var(--bg-color);
    color: var(--text-main);
    font-family: var(--font-main);
    line-height: 1.8;
    -webkit-font-smoothing: antialiased;
    overflow-x: hidden;
}

a {
    text-decoration: none;
    color: inherit;
    transition: all 0.3s ease;
    position: relative;
}

/* Enhanced Link Hover */
a:not(.logo):not(.btn):hover {
    color: var(--accent-color);
}

ul {
    list-style: none;
}

img {
    max-width: 100%;
    display: block;
    transition: transform 0.6s ease, filter 0.6s ease;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-weight: 400;
    letter-spacing: 0.05em;
}

.en-text {
    font-family: var(--font-eng);
    font-style: italic;
}

/* Layout Utilities */
.container {
    width: 90%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-sm);
}

.section {
    padding: var(--spacing-xl) 0;
    position: relative;
}

/* Grid Utilities */
.grid-2-cols {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-xl);
    align-items: center;
}

.grid-3-cols {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-md);
}

.grid-auto-fit {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-md);
}

/* Header & Navigation */
header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    padding: var(--spacing-md) 0;
    z-index: 100;
    transition: all 0.4s cubic-bezier(0.25, 0.46, 0.45, 0.94);
}

header.scrolled {
    background-color: rgba(250, 250, 248, 0.85);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    padding: var(--spacing-sm) 0;
    box-shadow: 0 2px 20px rgba(0,0,0,0.02);
}

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

.logo {
    font-size: 1.5rem;
    letter-spacing: 0.1em;
    z-index: 101;
    transition: transform 0.3s ease;
}

.logo:hover {
    transform: scale(1.02);
}

.nav-links {
    display: flex;
    gap: var(--spacing-md);
}

.nav-links a {
    font-size: 0.9rem;
    letter-spacing: 0.1em;
    padding-bottom: 2px;
}

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    width: 0;
    height: 1px;
    background-color: var(--accent-color);
    transition: width 0.4s cubic-bezier(0.25, 0.8, 0.25, 1);
}

.nav-links a:hover::after {
    width: 100%;
}

/* Mobile Menu */
.hamburger {
    display: none;
    cursor: pointer;
    z-index: 101;
}

.bar {
    display: block;
    width: 25px;
    height: 2px;
    margin: 6px auto;
    background-color: var(--text-main);
    transition: all 0.3s ease;
}

/* Hamburger Animation */
.hamburger.is-active .bar:nth-child(1) {
    transform: translateY(8px) rotate(45deg);
}

.hamburger.is-active .bar:nth-child(2) {
    opacity: 0;
}

.hamburger.is-active .bar:nth-child(3) {
    transform: translateY(-8px) rotate(-45deg);
}

/* Hero Split Layout */
.hero-split {
    display: flex;
    height: 100vh;
    height: 100dvh;
    width: 100%;
    position: relative;
    padding-top: 80px; /* Header height */
}

.hero-split-text {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: var(--bg-color);
    padding: var(--spacing-md);
    position: relative;
    z-index: 1;
}

.hero-text-content {
    max-width: 500px;
    text-align: left;
    padding: 0 var(--spacing-md);
}

.hero-split-text h1 {
    font-size: 4rem;
    margin-bottom: var(--spacing-xs);
    line-height: 1.1;
    font-weight: 300;
}

.hero-split-text .en-text {
    font-size: 1.5rem;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-md);
    display: block;
}

.hero-split-text .sub-text {
    font-size: 1.1rem;
    margin-bottom: var(--spacing-md);
    color: var(--accent-color);
}

.hero-split-text .divider {
    width: 60px;
    height: 1px;
    background-color: var(--text-main);
    margin: var(--spacing-md) 0;
}

.hero-split-text .description-text {
    font-size: 1rem;
    line-height: 1.8;
    color: var(--text-secondary);
}

.hero-split-image {
    flex: 1.2; /* Image takes slightly more space */
    height: 100%;
    overflow: hidden;
    position: relative;
}

.hero-split-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    object-position: center;
}

/* Scroll Indicator Dark Version */
.scroll-indicator.dark span {
    background: linear-gradient(to bottom, var(--text-main) 0%, transparent 100%);
}

.scroll-indicator.dark {
    left: 25%; /* Center under text section */
}

/* Responsive Split */
@media (max-width: 768px) {
    .hero-split {
        flex-direction: column-reverse; /* Text below image on mobile */
        height: auto;
        min-height: 100vh;
        padding-top: 60px;
    }

    .hero-split-image {
        flex: none;
        height: 60vh; /* Image takes 60% of viewport height */
        width: 100%;
    }

    .hero-split-text {
        flex: none;
        padding: var(--spacing-lg) var(--spacing-sm);
        text-align: center;
    }

    .hero-text-content {
        text-align: center;
        max-width: 100%;
        padding: 0;
    }

    .hero-split-text .divider {
        margin: var(--spacing-md) auto; /* Center divider */
    }

    .hero-split-text h1 {
        font-size: 2.5rem;
    }

    .hero-split-text .en-text {
        font-size: 1.2rem;
    }

    .scroll-indicator.dark {
        display: none; /* Hide on mobile split layout as it might overlap content */
    }
}

/* Scroll Indicator */
.scroll-indicator {
    position: absolute;
    bottom: 40px;
    left: 50%;
    transform: translateX(-50%);
    opacity: 0;
    animation: fadeIn 1s ease forwards 2s, bounce 2s infinite 3s;
    cursor: pointer;
    z-index: 10;
}

.scroll-indicator span {
    display: block;
    width: 1px;
    height: 60px;
    background: linear-gradient(to bottom, var(--text-main) 0%, transparent 100%);
    margin: 0 auto;
}

.scroll-indicator p {
    font-size: 0.7rem;
    letter-spacing: 0.2em;
    margin-top: 10px;
    text-transform: uppercase;
    color: var(--text-secondary);
}

/* Image Hover Effects */
.img-wrapper {
    overflow: hidden;
    position: relative;
}

.img-wrapper img {
    transition: transform 0.8s cubic-bezier(0.25, 0.46, 0.45, 0.94);
}

.img-wrapper:hover img {
    /* transform: scale(1.05); */
}

/* Animations Keyframes */
@keyframes scaleUp {
    from { transform: scale(1.05); }
    to { transform: scale(1.15); }
}

@keyframes fadeUp {
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes fadeIn {
    to { opacity: 1; }
}

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

/* Scroll Animation Classes */
.animate-on-scroll {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 1s ease, transform 1s ease;
}

.animate-on-scroll.is-visible {
    opacity: 1;
    transform: translateY(0);
}

/* Staggered Delays */
.delay-100 { transition-delay: 0.1s; }
.delay-200 { transition-delay: 0.2s; }
.delay-300 { transition-delay: 0.3s; }

/* Responsive */
@media (max-width: 768px) {
    :root {
        --spacing-xl: 4rem;
        --spacing-lg: 3rem;
        --spacing-md: 1.5rem;
    }

    .section {
        padding: var(--spacing-lg) 0;
    }

    .nav-links {
        position: fixed;
        left: -100%;
        top: 0;
        flex-direction: column;
        background-color: var(--bg-color);
        width: 100%;
        height: 100vh;
        justify-content: center;
        align-items: center;
        transition: 0.4s cubic-bezier(0.77, 0, 0.175, 1);
        z-index: 99;
    }

    .nav-links.active {
        left: 0;
    }

    .hamburger {
        display: block;
    }
    
    .hero {
        align-items: flex-end; /* Align text to bottom on mobile */
        padding-bottom: 20vh;
    }

    .hero h1 {
        font-size: 2.5rem;
        margin-bottom: 0.5rem;
    }

    .hero p {
        font-size: 1rem;
        letter-spacing: 0.1em;
    }

    .hero p.sub-text {
        font-size: 0.85rem;
        margin-top: 10px;
        opacity: 0.9;
    }
    
    .hero-bg img {
        animation: none;
        transform: scale(1);
        object-position: center center;
    }

    /* .hero-overlay {
        background: linear-gradient(to bottom, rgba(250, 250, 248, 0.1) 0%, rgba(250, 250, 248, 0.6) 100%); 
    } */

    /* Grid Stacking */
    .grid-2-cols, .grid-3-cols {
        grid-template-columns: 1fr;
        gap: var(--spacing-md);
    }

    /* Adjust specific layout items */
    .grid-2-cols > div {
        order: 0;
    }
    
    /* Reverse order for image/text alternating if needed, or keep standard flow */
}