/* ============================================
   CSS Variables - Apple Dark Theme
   ============================================ */
:root {
    /* Colors */
    --bg-primary: #000000;
    --bg-secondary: #050505;
    --bg-card: #1a1a1a;
    --bg-card-hover: #252525;
    --text-primary: #ffffff;
    --text-secondary: #a1a1a6;
    --text-tertiary: #6e6e73;
    --accent-blue: #0071e3;
    --accent-blue-hover: #0077ed;
    
    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --spacing-xxl: 4rem;
    --spacing-section: 5rem;
    --spacing-section-mobile: 3rem;
    
    /* Typography */
    --font-family: "SF Pro Text", "SF Pro Display", -apple-system, BlinkMacSystemFont, system-ui, sans-serif;
    --font-size-base: 17px;
    --font-size-sm: 14px;
    --font-size-lg: 19px;
    --font-size-xl: 24px;
    --font-size-xxl: 32px;
    --font-size-hero: 56px;
    --font-size-hero-mobile: 40px;
    
    /* Layout */
    --container-max-width: 1200px;
    --container-padding: 1.25rem;
    
    /* Border & Shadow */
    --border-radius-sm: 12px;
    --border-radius-md: 16px;
    --border-radius-lg: 24px;
    --border-radius-xl: 28px;
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.5);
    
    /* Transitions */
    --transition-fast: 0.2s ease;
    --transition-base: 0.3s ease;
    --transition-slow: 0.5s ease;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--bg-primary);
    overflow-x: hidden;
}
/* Menu con trong "Sản phẩm" */
.nav-dropdown {
    position: absolute;
    top: 100%;
    left: 0;
    margin-top: 0.75rem;
    padding: 0.6rem;
    background: rgba(15, 15, 20, 0.96);
    border-radius: 18px;
    box-shadow: 0 18px 45px rgba(0, 0, 0, 0.85);
    min-width: 180px;
  }
  
  .nav-dropdown a {
    display: block;
    padding: 0.7rem 1.1rem;
    border-radius: 12px;
    font-size: 0.95rem;
    color: #f5f5f7;        /* luôn trắng, không tím */
  }
  
  .nav-dropdown a:hover {
    background: rgba(255, 255, 255, 0.08);
    color: #f5f5f7;
  }  
/* ============================================
   Container
   ============================================ */
.container {
    max-width: var(--container-max-width);
    margin: 0 auto;
    padding-inline: var(--container-padding);
}

/* ============================================
   Header
   ============================================ */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background-color: rgba(0, 0, 0, 0.8);
    backdrop-filter: saturate(180%) blur(20px);
    -webkit-backdrop-filter: saturate(180%) blur(20px);
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    transition: var(--transition-base);
}

.header-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--spacing-sm) 0;
    min-height: 60px;
}

.logo-wrapper {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    text-decoration: none;
    color: var(--text-primary);
}

.logo {
    width: 32px;
    height: 32px;
    object-fit: contain;
}

.logo-text {
    font-size: var(--font-size-lg);
    font-weight: 600;
    letter-spacing: -0.5px;
}

/* Desktop Navigation */
.nav-desktop {
    display: none;
    align-items: center;
    gap: var(--spacing-md);
}

@media (min-width: 769px) {
    .nav-desktop {
        display: flex;
    }
}

.nav-link {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: var(--font-size-base);
    transition: var(--transition-fast);
    position: relative;
    padding: var(--spacing-xs) 0;
}

.nav-link:hover {
    color: var(--text-primary);
}

.nav-item {
    position: relative;
}

.nav-dropdown {
    position: absolute;
    top: 100%;
    left: 50%;
    transform: translateX(-50%);
    margin-top: var(--spacing-sm);
    background-color: rgba(26, 26, 26, 0.95);
    backdrop-filter: blur(20px);
    border-radius: var(--border-radius-md);
    padding: var(--spacing-xs) 0;
    min-width: 160px;
    opacity: 0;
    visibility: hidden;
    transform: translateX(-50%) translateY(-10px);
    transition: var(--transition-base);
    list-style: none;
    box-shadow: var(--shadow-lg);
    border: 1px solid rgba(255, 255, 255, 0.1);
}

.has-dropdown:hover .nav-dropdown {
    opacity: 1;
    visibility: visible;
    transform: translateX(-50%) translateY(0);
}

.dropdown-link {
    display: block;
    padding: var(--spacing-xs) var(--spacing-md);
    color: var(--text-secondary);
    text-decoration: none;
    transition: var(--transition-fast);
}

.dropdown-link:hover {
    color: var(--text-primary);
    background-color: rgba(255, 255, 255, 0.05);
}

/* Mobile Menu Toggle */
.menu-toggle {
    display: flex;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: var(--spacing-xs);
    z-index: 1001;
}

@media (min-width: 769px) {
    .menu-toggle {
        display: none;
    }
}

.menu-toggle span {
    width: 24px;
    height: 2px;
    background-color: var(--text-primary);
    transition: var(--transition-base);
    border-radius: 2px;
}

.menu-toggle.active span:nth-child(1) {
    transform: rotate(45deg) translate(6px, 6px);
}

.menu-toggle.active span:nth-child(2) {
    opacity: 0;
}

.menu-toggle.active span:nth-child(3) {
    transform: rotate(-45deg) translate(6px, -6px);
}

/* Mobile Navigation */
.nav-mobile {
    display: none;
    flex-direction: column;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background-color: rgba(0, 0, 0, 0.95);
    backdrop-filter: blur(20px);
    padding: var(--spacing-lg);
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    gap: var(--spacing-md);
}

.nav-mobile.active {
    display: flex;
}

@media (min-width: 769px) {
    .nav-mobile {
        display: none !important;
    }
}

.nav-mobile .nav-link {
    padding: var(--spacing-sm) 0;
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
}

/* ============================================
   Hero Section
   ============================================ */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding-top: 80px;
    padding-bottom: var(--spacing-xxl);
    text-align: center;
}

.hero-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-lg);
    max-width: 800px;
}

.hero-title {
    font-size: var(--font-size-hero-mobile);
    font-weight: 700;
    letter-spacing: -1.5px;
    line-height: 1.1;
    margin-bottom: var(--spacing-sm);
}

@media (min-width: 769px) {
    .hero-title {
        font-size: var(--font-size-hero);
    }
}

.hero-subtitle {
    font-size: var(--font-size-lg);
    color: var(--text-secondary);
    max-width: 600px;
    margin-bottom: var(--spacing-md);
}

.hero-buttons {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-md);
    justify-content: center;
    margin-bottom: var(--spacing-xl);
}

.hero-image-wrapper {
    width: 100%;
    max-width: 600px;
    margin-top: var(--spacing-lg);
}

.hero-image {
    width: 100%;
    height: auto;
    object-fit: contain;
    border-radius: var(--border-radius-xl);
    box-shadow: var(--shadow-lg);
    filter: drop-shadow(0 20px 40px rgba(0, 113, 227, 0.2));
}

/* ============================================
   Buttons
   ============================================ */
.btn {
    display: inline-block;
    padding: var(--spacing-sm) var(--spacing-lg);
    border-radius: var(--border-radius-md);
    text-decoration: none;
    font-size: var(--font-size-base);
    font-weight: 500;
    transition: var(--transition-base);
    cursor: pointer;
    border: none;
    text-align: center;
}

.btn-primary {
    background-color: var(--accent-blue);
    color: var(--text-primary);
}

.btn-primary:hover {
    background-color: var(--accent-blue-hover);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 113, 227, 0.4);
}

.btn-secondary {
    background-color: rgba(255, 255, 255, 0.1);
    color: var(--text-primary);
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.btn-secondary:hover {
    background-color: rgba(255, 255, 255, 0.15);
    border-color: rgba(255, 255, 255, 0.3);
    transform: translateY(-2px);
}

.btn-small {
    padding: var(--spacing-xs) var(--spacing-md);
    font-size: var(--font-size-sm);
}

.btn-large {
    padding: var(--spacing-md) var(--spacing-xl);
    font-size: var(--font-size-lg);
}

/* ============================================
   Sections
   ============================================ */
.section {
    padding: var(--spacing-section-mobile) 0;
}

@media (min-width: 769px) {
    .section {
        padding: var(--spacing-section) 0;
    }
}

.section-title {
    font-size: var(--font-size-xxl);
    font-weight: 700;
    text-align: center;
    margin-bottom: var(--spacing-sm);
    letter-spacing: -0.5px;
}

.section-subtitle {
    font-size: var(--font-size-lg);
    color: var(--text-secondary);
    text-align: center;
    margin-bottom: var(--spacing-xl);
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

/* ============================================
   Models Section
   ============================================ */
/* Lưới sản phẩm chuẩn Apple */
.models-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 2.5rem;
    margin-top: 2.5rem;
  }

@media (min-width: 640px) {
    .models-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (min-width: 1024px) {
    .models-grid {
        grid-template-columns: repeat(4, 1fr);
    }
}
/* Card sản phẩm */
.product-card {
  background: radial-gradient(circle at top, #1b1b1f, #050506 65%);
  border-radius: 28px;
  padding: 2.2rem 1.8rem 2.4rem;
  box-shadow: 0 26px 60px rgba(0, 0, 0, 0.8);
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  transition: transform 0.35s ease, box-shadow 0.35s ease, background 0.35s ease;
}

/* Hiệu ứng hover nhẹ kiểu Apple */
.product-card:hover {
  transform: translateY(-8px);
  box-shadow: 0 40px 80px rgba(0, 0, 0, 0.95);
  background: radial-gradient(circle at top, #22222a, #050506 70%);
}

.product-card {
    background: linear-gradient(135deg, var(--bg-card) 0%, var(--bg-secondary) 100%);
    border-radius: var(--border-radius-xl);
    padding: var(--spacing-lg);
    text-align: center;
    transition: var(--transition-base);
    border: 1px solid rgba(255, 255, 255, 0.05);
    opacity: 0;
    transform: translateY(30px);
}

.product-card.reveal {
    opacity: 1;
    transform: translateY(0);
}

.product-card:hover {
    transform: translateY(-8px) scale(1.02);
    box-shadow: var(--shadow-lg);
    border-color: rgba(255, 255, 255, 0.1);
}

.product-image-wrapper {
    height: 280px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: var(--spacing-md);
    background: linear-gradient(135deg, rgba(255, 255, 255, 0.02) 0%, rgba(255, 255, 255, 0.05) 100%);
    border-radius: var(--border-radius-lg);
    padding: var(--spacing-md);
}

.product-image {
    width: 100%;
    max-width: 260px;
    height: 100%;
    object-fit: contain;
}

.product-name {
    font-size: var(--font-size-xl);
    font-weight: 600;
    margin-bottom: var(--spacing-xs);
    letter-spacing: -0.3px;
}

.product-description {
    font-size: var(--font-size-sm);
    color: var(--text-secondary);
    margin-bottom: var(--spacing-md);
    line-height: 1.5;
    min-height: 60px;
}

.product-price {
    font-size: var(--font-size-lg);
    font-weight: 600;
    color: var(--accent-blue);
    margin-bottom: var(--spacing-md);
}

/* ============================================
   Features Section
   ============================================ */
.features {
    background-color: var(--bg-secondary);
}

.features-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--spacing-xl);
    margin-top: var(--spacing-xl);
}

@media (min-width: 768px) {
    .features-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

.feature-card {
    background-color: var(--bg-card);
    border-radius: var(--border-radius-lg);
    padding: var(--spacing-xl);
    text-align: center;
    border: 1px solid rgba(255, 255, 255, 0.05);
    opacity: 0;
    transform: translateY(30px);
    transition: var(--transition-base);
}

.feature-card.reveal {
    opacity: 1;
    transform: translateY(0);
}

.feature-card:hover {
    transform: translateY(-4px);
    border-color: rgba(255, 255, 255, 0.1);
    box-shadow: var(--shadow-md);
}

.feature-icon {
    width: 64px;
    height: 64px;
    margin: 0 auto var(--spacing-md);
    background: linear-gradient(135deg, rgba(0, 113, 227, 0.2) 0%, rgba(0, 113, 227, 0.1) 100%);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--accent-blue);
}

.feature-icon svg {
    width: 32px;
    height: 32px;
}

.feature-title {
    font-size: var(--font-size-xl);
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
    letter-spacing: -0.3px;
}

.feature-description {
    font-size: var(--font-size-base);
    color: var(--text-secondary);
    line-height: 1.6;
}

/* ============================================
   Accessories Section
   ============================================ */
.accessories-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--spacing-xl);
    margin-top: var(--spacing-xl);
}

@media (min-width: 640px) {
    .accessories-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (min-width: 1024px) {
    .accessories-grid {
        grid-template-columns: repeat(3, 1fr);
    }
}

.accessory-placeholder {
    background: linear-gradient(135deg, rgba(0, 113, 227, 0.1) 0%, rgba(0, 113, 227, 0.05) 100%);
}

.accessory-icon {
    font-size: 64px;
    opacity: 0.8;
}

/* ============================================
   Contact Section
   ============================================ */
.contact {
    background-color: var(--bg-secondary);
}

.contact-content {
    max-width: 700px;
    margin: 0 auto;
    text-align: center;
}

.contact-buttons {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-md);
    justify-content: center;
    margin-bottom: var(--spacing-xl);
}

.contact-info {
    margin-top: var(--spacing-xl);
    text-align: left;
    display: grid;
    gap: var(--spacing-lg);
}

@media (min-width: 640px) {
    .contact-info {
        grid-template-columns: repeat(2, 1fr);
    }
}

.info-item {
    padding: var(--spacing-md);
    background-color: var(--bg-card);
    border-radius: var(--border-radius-md);
    border: 1px solid rgba(255, 255, 255, 0.05);
}

.info-item strong {
    display: block;
    color: var(--text-primary);
    margin-bottom: var(--spacing-xs);
    font-size: var(--font-size-sm);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.info-item p {
    color: var(--text-secondary);
    font-size: var(--font-size-base);
}

.info-item a {
    color: var(--accent-blue);
    text-decoration: none;
    transition: var(--transition-fast);
}

.info-item a:hover {
    color: var(--accent-blue-hover);
}

/* ============================================
   Footer
   ============================================ */
.footer {
    background-color: var(--bg-primary);
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    padding: var(--spacing-xl) 0;
    text-align: center;
}

.footer-text {
    font-size: var(--font-size-sm);
    color: var(--text-tertiary);
    margin-bottom: var(--spacing-sm);
}

.footer-link {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: var(--font-size-sm);
    transition: var(--transition-fast);
}

.footer-link:hover {
    color: var(--text-primary);
}

/* ============================================
   Reveal Animation
   ============================================ */
.reveal {
    transition: opacity 0.6s ease, transform 0.6s ease;
}