/* ==========================================================================
   1. CSS Reset & Variables
   ========================================================================== */
:root {
    /* Color Palette */
    --color-bg: #FFFFFF;
    --color-bg-alt: #F8F9FA;
    --color-bg-dark: #2C2C2C;
    --color-text-main: #333333;
    --color-text-sub: #666666;
    --color-text-light: #999999;
    --color-accent: #E3D5C8; /* Spring Theme Accent */
    --color-border: #E9ECEF;
    
    /* Spacing */
    --spacing-xs: 0.5rem;  /* 8px */
    --spacing-sm: 1rem;    /* 16px */
    --spacing-md: 2rem;    /* 32px */
    --spacing-lg: 4rem;    /* 64px */
    --spacing-xl: 8rem;    /* 128px */

    /* Typography */
    --font-primary: "Helvetica Now Display", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
    --font-size-base: 16px;
    --font-size-sm: 14px;
    --font-size-lg: 20px;
    --font-size-xl: 28px;
    --font-size-xxl: 40px;

    /* Layout */
    --container-width: 1440px;
    --header-height: 80px;
    
    /* Transitions */
    --transition-base: all 0.4s cubic-bezier(0.25, 0.46, 0.45, 0.94);
    --transition-slow: all 0.8s cubic-bezier(0.16, 1, 0.3, 1);
}

*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-primary);
    background-color: var(--color-bg);
    color: var(--color-text-main);
    line-height: 1.6;
    overflow-x: hidden;
}

a {
    text-decoration: none;
    color: inherit;
    transition: var(--transition-base);
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

ul, ol {
    list-style: none;
}

button {
    border: none;
    background: none;
    cursor: pointer;
    font-family: inherit;
    outline: none;
}

/* ==========================================================================
   2. Typography
   ========================================================================== */
h1, h2, h3, h4, h5, h6 {
    font-weight: 400;
    line-height: 1.3;
    letter-spacing: -0.02em;
    margin-bottom: var(--spacing-sm);
}

.text-display {
    font-size: var(--font-size-xxl);
    font-weight: 300;
}

.text-title {
    font-size: var(--font-size-xl);
    margin-bottom: var(--spacing-md);
}

.text-subtitle {
    font-size: var(--font-size-lg);
    color: var(--color-text-sub);
    margin-bottom: var(--spacing-sm);
}

.text-body {
    font-size: var(--font-size-base);
    color: var(--color-text-main);
}

.text-small {
    font-size: var(--font-size-sm);
    color: var(--color-text-sub);
}

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

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

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

.flex-center {
    display: flex;
    justify-content: center;
    align-items: center;
}

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

.grid-base {
    display: grid;
    gap: var(--spacing-md);
}

/* ==========================================================================
   4. Components: Navigation
   ========================================================================== */
.main-header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: var(--header-height);
    background-color: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    z-index: 1000;
    border-bottom: 1px solid transparent;
    transition: border-color 0.3s ease;
}

.main-header.scrolled {
    border-bottom: 1px solid var(--color-border);
}

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

.logo {
    font-size: 1.5rem;
    font-weight: 500;
    letter-spacing: 0.05em;
    text-transform: uppercase;
    z-index: 1002;
}

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

.nav-links a {
    position: relative;
    font-size: var(--font-size-sm);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--color-text-main);
    padding-bottom: 4px;
}

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 1px;
    background-color: var(--color-text-main);
    transition: width 0.3s ease;
}

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

/* Mobile Menu Toggle */
.mobile-menu-btn {
    display: none;
    flex-direction: column;
    justify-content: space-between;
    width: 24px;
    height: 18px;
    z-index: 1002;
}

.mobile-menu-btn span {
    display: block;
    width: 100%;
    height: 1px;
    background-color: var(--color-text-main);
    transition: var(--transition-base);
}

/* ==========================================================================
   5. Components: Hero & Carousel
   ========================================================================== */
.hero-section {
    position: relative;
    height: 100vh;
    width: 100%;
    overflow: hidden;
}

.hero-slider {
    width: 100%;
    height: 100%;
    position: relative;
}

.hero-slide {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    opacity: 0;
    transition: opacity 1.5s ease;
    z-index: 1;
}

.hero-slide.active {
    opacity: 1;
    z-index: 2;
}

.hero-slide img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    object-position: center;
    transform: scale(1.05);
    transition: transform 8s linear;
}

.hero-slide.active img {
    transform: scale(1);
}

.hero-content {
    position: absolute;
    bottom: 15%;
    left: 5%;
    z-index: 10;
    color: white;
    max-width: 600px;
    opacity: 0;
    transform: translateY(20px);
    transition: var(--transition-slow);
    transition-delay: 0.5s;
}

.hero-slide.active ~ .hero-content,
.hero-content.visible {
    opacity: 1;
    transform: translateY(0);
}

.hero-title {
    font-size: 3.5rem;
    margin-bottom: var(--spacing-sm);
    text-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

.btn-explore {
    display: inline-block;
    padding: 12px 32px;
    border: 1px solid white;
    color: white;
    font-size: var(--font-size-sm);
    letter-spacing: 0.1em;
    text-transform: uppercase;
    transition: var(--transition-base);
}

.btn-explore:hover {
    background-color: white;
    color: var(--color-text-main);
}

/* ==========================================================================
   6. Components: Grids & Cards
   ========================================================================== */
.grid-3-col {
    grid-template-columns: repeat(3, 1fr);
}

.grid-2-col {
    grid-template-columns: repeat(2, 1fr);
}

.card-product {
    group: product;
}

.card-image-wrapper {
    position: relative;
    overflow: hidden;
    margin-bottom: var(--spacing-sm);
    aspect-ratio: 3/4;
    background-color: var(--color-bg-alt);
}

.card-image-wrapper img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.6s ease;
}

.card-product:hover .card-image-wrapper img {
    transform: scale(1.05);
}

.card-info {
    text-align: left;
}

.card-title {
    font-size: var(--font-size-base);
    margin-bottom: 4px;
    font-weight: 400;
}

.card-meta {
    font-size: var(--font-size-sm);
    color: var(--color-text-sub);
    display: flex;
    gap: 8px;
}

.card-meta span + span::before {
    content: "·";
    margin-right: 8px;
}

/* ==========================================================================
   7. Components: Filters
   ========================================================================== */
.filter-bar {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
    padding-top: var(--spacing-md);
}

.filter-btn {
    font-size: var(--font-size-sm);
    color: var(--color-text-sub);
    padding: 8px 16px;
    border-radius: 20px;
    transition: var(--transition-base);
}

.filter-btn:hover,
.filter-btn.active {
    color: var(--color-text-main);
    background-color: var(--color-bg-alt);
}

/* ==========================================================================
   8. Components: Seasonal & Materials
   ========================================================================== */
.seasonal-section {
    background-color: var(--color-bg-alt);
}

.split-layout {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-lg);
    align-items: center;
}

.split-content {
    padding: var(--spacing-md);
}

.material-card {
    background-color: white;
    padding: var(--spacing-sm);
    transition: var(--transition-base);
}

.material-card:hover {
    box-shadow: 0 10px 30px rgba(0,0,0,0.03);
}

/* ==========================================================================
   9. Components: Philosophy & Styling
   ========================================================================== */
.philosophy-block {
    margin-bottom: var(--spacing-xl);
}

.philosophy-block:nth-child(even) .split-layout {
    direction: rtl; /* Swap image/text */
}
.philosophy-block:nth-child(even) .split-content {
    direction: ltr;
    text-align: right;
}

.style-board {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-xl);
}

.style-main-img {
    aspect-ratio: 3/4;
    width: 100%;
    object-fit: cover;
}

.style-items {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.style-item-img {
    aspect-ratio: 1/1;
    object-fit: cover;
    background-color: var(--color-bg-alt);
}

/* ==========================================================================
   10. Footer
   ========================================================================== */
.main-footer {
    padding: var(--spacing-lg) 0;
    border-top: 1px solid var(--color-border);
    text-align: center;
    margin-top: auto;
}

.footer-content p {
    font-size: var(--font-size-sm);
    color: var(--color-text-sub);
    letter-spacing: 0.1em;
}

/* ==========================================================================
   11. Utility Animations
   ========================================================================== */
.fade-in-up {
    opacity: 0;
    transform: translateY(20px);
    animation: fadeInUp 0.8s ease forwards;
}

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

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

/* ==========================================================================
   12. Responsive Design
   ========================================================================== */
/* Tablet (max-width: 1024px) */
@media (max-width: 1024px) {
    :root {
        --spacing-xl: 5rem;
        --spacing-lg: 3rem;
    }
    
    .grid-3-col {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .hero-title {
        font-size: 2.5rem;
    }
}

/* Mobile (max-width: 768px) */
@media (max-width: 768px) {
    :root {
        --header-height: 60px;
        --spacing-xl: 4rem;
    }

    .text-display {
        font-size: 2rem;
    }
    
    .mobile-menu-btn {
        display: flex;
    }

    .nav-links {
        position: fixed;
        top: var(--header-height);
        left: 0;
        width: 100%;
        height: calc(100vh - var(--header-height));
        background-color: var(--color-bg);
        flex-direction: column;
        padding: var(--spacing-lg);
        gap: var(--spacing-md);
        transform: translateX(100%);
        transition: transform 0.4s ease;
        align-items: center;
        justify-content: center;
    }

    .nav-links.active {
        transform: translateX(0);
    }
    
    .nav-links a {
        font-size: 1.25rem;
    }

    .split-layout,
    .style-board {
        grid-template-columns: 1fr;
        gap: var(--spacing-md);
    }
    
    .philosophy-block:nth-child(even) .split-layout {
        direction: ltr;
    }
    
    .philosophy-block:nth-child(even) .split-content {
        text-align: left;
    }
    
    .style-items {
        display: grid;
        grid-template-columns: repeat(3, 1fr);
    }

    .grid-3-col, .grid-2-col {
        grid-template-columns: 1fr;
    }
    
    .filter-bar {
        overflow-x: auto;
        justify-content: flex-start;
        padding-bottom: var(--spacing-sm);
        flex-wrap: nowrap;
        -webkit-overflow-scrolling: touch;
    }
    
    .filter-btn {
        white-space: nowrap;
    }
}