/* ===================================
   MAIN.CSS - Global Layout & Components
   Mobile-First Approach
   =================================== */

/* ===================================
   CSS RESET & BASE STYLES
   =================================== */
*,
*::before,
*::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

:root {
    /* Colors */
    --color-primary: #0066FF;
    --color-primary-dark: #0052CC;
    --color-primary-light: #3385FF;
    --color-secondary: #00D4FF;
    --color-accent: #FF6B6B;
    
    --color-text-primary: #1a1a1a;
    --color-text-secondary: #666666;
    --color-text-tertiary: #999999;
    
    --color-bg-primary: #FFFFFF;
    --color-bg-secondary: #F8F9FA;
    --color-bg-tertiary: #F0F2F5;
    
    --color-border: #E1E4E8;
    --color-border-light: #F0F2F5;
    
    --color-success: #28A745;
    --color-warning: #FFC107;
    --color-error: #DC3545;
    
    /* Typography */
    --font-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-secondary: 'Roboto Slab', Georgia, serif;
    
    --font-size-xs: 12px;
    --font-size-sm: 14px;
    --font-size-base: 16px;
    --font-size-lg: 18px;
    --font-size-xl: 20px;
    --font-size-2xl: 24px;
    --font-size-3xl: 30px;
    --font-size-4xl: 36px;
    --font-size-5xl: 48px;
    
    --font-weight-light: 300;
    --font-weight-normal: 400;
    --font-weight-medium: 500;
    --font-weight-semibold: 600;
    --font-weight-bold: 700;
    
    --line-height-tight: 1.25;
    --line-height-normal: 1.5;
    --line-height-relaxed: 1.75;
    
    /* Spacing */
    --spacing-xs: 4px;
    --spacing-sm: 8px;
    --spacing-md: 16px;
    --spacing-lg: 24px;
    --spacing-xl: 32px;
    --spacing-2xl: 48px;
    --spacing-3xl: 64px;
    --spacing-4xl: 96px;
    
    /* Layout */
    --container-width-sm: 640px;
    --container-width-md: 768px;
    --container-width-lg: 1024px;
    --container-width-xl: 1280px;
    --container-width-2xl: 1440px;
    
    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
    
    /* Border Radius */
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --radius-xl: 16px;
    --radius-full: 9999px;
    
    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 250ms ease;
    --transition-slow: 350ms ease;
    
    /* Z-index */
    --z-dropdown: 1000;
    --z-sticky: 1020;
    --z-fixed: 1030;
    --z-modal-backdrop: 1040;
    --z-modal: 1050;
    --z-popover: 1060;
    --z-tooltip: 1070;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* Theme Management */
html[data-theme="dark"] {
    --color-text-primary: #E8EAED;
    --color-text-secondary: #BDC1C6;
    --color-text-tertiary: #9AA0A6;
    
    --color-bg-primary: #1F1F1F;
    --color-bg-secondary: #2D2D2D;
    --color-bg-tertiary: #3C3C3C;
    
    --color-border: #3C4043;
    --color-border-light: #2D2D2D;
}

body {
    font-family: var(--font-primary);
    font-size: var(--font-size-base);
    font-weight: var(--font-weight-normal);
    line-height: var(--line-height-normal);
    color: var(--color-text-primary);
    background-color: var(--color-bg-primary);
    overflow-x: hidden;
}

body.menu-open {
    overflow: hidden;
}

/* ===================================
   TYPOGRAPHY
   =================================== */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-secondary);
    font-weight: var(--font-weight-bold);
    line-height: var(--line-height-tight);
    color: var(--color-text-primary);
    margin-bottom: var(--spacing-md);
}

a {
    color: var(--color-primary);
    text-decoration: none;
    transition: color var(--transition-fast);
}

a:hover {
    color: var(--color-primary-dark);
}

a:focus-visible {
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
    border-radius: var(--radius-sm);
}

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

/* ===================================
   HEADER
   =================================== */
.header {
    position: sticky;
    top: 0;
    width: 100%;
    background-color: var(--color-bg-primary);
    border-bottom: 1px solid var(--color-border);
    z-index: var(--z-sticky);
    box-shadow: var(--shadow-sm);
}

.header__container {
    max-width: var(--container-width-lg);
    margin: 0 auto;
    padding: var(--spacing-md) var(--spacing-md);
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: var(--spacing-md);
}

/* Logo */
.header__logo {
    flex: 1;
    display: flex;
    justify-content: center;
}

.logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-size: var(--font-size-lg);
    font-weight: var(--font-weight-semibold);
    color: var(--color-text-primary);
    transition: opacity var(--transition-fast);
}

.logo:hover {
    opacity: 0.8;
}

.logo__icon {
    width: 32px;
    height: 32px;
}

.logo__text strong {
    color: var(--color-primary);
}

/* Mobile Menu Toggle */
.menu-toggle-checkbox {
    display: none;
}

.header__menu-toggle {
    display: flex;
    flex-direction: column;
    justify-content: space-around;
    width: 28px;
    height: 28px;
    background: transparent;
    border: none;
    cursor: pointer;
    padding: 0;
    z-index: var(--z-fixed);
    order: -1;
    flex-shrink: 0;
}

.hamburger {
    width: 100%;
    height: 2px;
    background-color: var(--color-text-primary);
    border-radius: var(--radius-full);
    transition: all var(--transition-base);
    transform-origin: center;
}

/* Hamburger animation when menu is open */
.menu-toggle-checkbox:checked + .header .header__menu-toggle .hamburger:nth-child(1) {
    transform: translateY(9px) rotate(45deg);
}

.menu-toggle-checkbox:checked + .header .header__menu-toggle .hamburger:nth-child(2) {
    opacity: 0;
    transform: translateX(-20px);
}

.menu-toggle-checkbox:checked + .header .header__menu-toggle .hamburger:nth-child(3) {
    transform: translateY(-9px) rotate(-45deg);
}

/* Navigation - Mobile First */
.nav {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    max-width: 280px;
    height: 100vh;
    background-color: var(--color-bg-primary);
    box-shadow: var(--shadow-xl);
    transform: translateX(-100%);
    transition: transform var(--transition-base);
    z-index: calc(var(--z-fixed) - 1);
    padding: calc(var(--spacing-4xl) + var(--spacing-md)) var(--spacing-xl) var(--spacing-xl);
    overflow-y: auto;
}

html[data-theme="dark"] .nav {
    background-color: var(--color-bg-primary);
}

/* Show menu when checkbox is checked */
.menu-toggle-checkbox:checked + .header .nav {
    transform: translateX(0);
}

.nav--active {
    transform: translateX(0);
}

.nav__list {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.nav__item {
    width: 100%;
}

.nav__link {
    display: block;
    padding: var(--spacing-md);
    font-size: var(--font-size-base);
    font-weight: var(--font-weight-medium);
    color: var(--color-text-primary);
    border-radius: var(--radius-md);
    transition: all var(--transition-fast);
}

.nav__link:hover {
    color: #F00;
    box-shadow: 0 2px 0 0 #F00;
    transition: all 0.3s ease;
}

/* Mobile Menu Overlay */
.nav-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100vh;
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-base);
    z-index: calc(var(--z-fixed) - 2);
    cursor: pointer;
}

/* Show overlay when checkbox is checked */
.menu-toggle-checkbox:checked ~ .nav-overlay {
    opacity: 1;
    visibility: visible;
}

.nav-overlay.active {
    opacity: 1;
    visibility: visible;
}

/* Prevent body scroll when menu is open */
.menu-toggle-checkbox:checked ~ .main,
.menu-toggle-checkbox:checked ~ .footer {
    filter: blur(2px);
}

body.menu-open {
    overflow: hidden;
}

/* ===================================
   THEME TOGGLE BUTTON
   =================================== */
.theme-toggle {
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
    width: 50px;
    height: 50px;
    background-color: var(--color-bg-secondary);
    border: 2px solid var(--color-border);
    border-radius: 100%;
    cursor: pointer;
    transition: all var(--transition-base);
    margin-left: var(--spacing-md);
    flex-shrink: 0;
}

.theme-toggle:hover {
    background-color: var(--color-bg-tertiary);
    border-color: var(--color-primary);
    transform: scale(1.05);
}

.theme-toggle:active {
    transform: scale(0.95);
}

.theme-toggle:focus-visible {
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
}

.theme-toggle__icon {
    position: absolute;
    transition: all var(--transition-base);
    color: var(--color-text-primary);
}

.theme-toggle__icon--sun {
    opacity: 1;
    transform: rotate(0deg) scale(1);
}

.theme-toggle__icon--moon {
    opacity: 0;
    transform: rotate(180deg) scale(0);
}

html[data-theme="dark"] .theme-toggle__icon--sun {
    opacity: 0;
    transform: rotate(-180deg) scale(0);
}

html[data-theme="dark"] .theme-toggle__icon--moon {
    opacity: 1;
    transform: rotate(0deg) scale(1);
}

.theme-toggle--animating {
    animation: togglePulse 0.3s ease;
}

@keyframes togglePulse {
    0%, 100% {
        transform: scale(1);
    }
    50% {
        transform: scale(1.1);
    }
}

/* ===================================
   MAIN CONTENT AREA
   =================================== */
.main {
    min-height: 100vh;
    background-color: var(--color-bg-secondary);
}

/* ===================================
   BREADCRUMB
   =================================== */
.breadcrumb {
    max-width: var(--container-width-lg);
    margin: 0 auto;
    padding: var(--spacing-md) var(--spacing-md);
    background-color: var(--color-bg-primary);
}

.breadcrumb__list {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: var(--spacing-xs);
    list-style: none;
    font-size: var(--font-size-sm);
}

.breadcrumb__item {
    display: flex;
    align-items: center;
    color: var(--color-text-tertiary);
}

.breadcrumb__item:not(:last-child)::after {
    content: '/';
    margin-left: var(--spacing-xs);
    color: var(--color-text-tertiary);
}

.breadcrumb__item a {
    color: var(--color-text-secondary);
    transition: color var(--transition-fast);
}

.breadcrumb__item a:hover {
    color: var(--color-primary);
}

.breadcrumb__item[aria-current="page"] {
    color: var(--color-text-primary);
    font-weight: var(--font-weight-medium);
}

/* ===================================
   FOOTER
   =================================== */
.footer {
    background-color: var(--color-text-primary);
    color: var(--color-bg-secondary);
}

.footer__container {
    max-width: var(--container-width-2xl);
    margin: 0 auto;
    padding: var(--spacing-2xl) var(--spacing-md) var(--spacing-md);
}

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

.footer__column {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.footer__logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-size: var(--font-size-xl);
    font-weight: var(--font-weight-bold);
    color: white;
}

.footer__logo strong {
    color: var(--color-secondary);
}

.footer__description {
    font-size: var(--font-size-sm);
    line-height: var(--line-height-relaxed);
    color: var(--color-text-tertiary);
    max-width: 400px;
}

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

.footer__social-link {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    background-color: rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-md);
    color: white;
    transition: all var(--transition-base);
}

.footer__social-link:hover {
    background-color: #F00;
    transform: translateY(-2px);
}

.footer__heading {
    font-family: var(--font-primary);
    font-size: var(--font-size-base);
    font-weight: var(--font-weight-semibold);
    color: white;
    margin-bottom: var(--spacing-sm);
}

.footer__links {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.footer__links a {
    font-size: var(--font-size-sm);
    color: var(--color-text-tertiary);
    transition: color var(--transition-fast);
    display: inline-block;
}

.footer__links a:hover {
    color: var(--color-secondary);
    padding-left: var(--spacing-xs);
}

.footer__bottom {
    padding-top: var(--spacing-md);
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    text-align: center;
}

.footer__copyright {
    margin: 0 var(--spacing-md);
    font-size: var(--font-size-sm);
    color: var(--color-text-tertiary);
}

/* ===================================
   UTILITY CLASSES
   =================================== */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border-width: 0;
}

.container {
    width: 100%;
    max-width: var(--container-width-2xl);
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

/* ===================================
   TABLET STYLES (min-width: 768px)
   =================================== */
@media (min-width: 768px) {
    :root {
        --font-size-3xl: 36px;
        --font-size-4xl: 44px;
        --font-size-5xl: 56px;
    }

    /* Header */
    .header__container {
        padding: var(--spacing-lg) var(--spacing-xl);
    }

    .logo__icon {
        width: 40px;
        height: 40px;
    }

    .logo__text {
        font-size: var(--font-size-xl);
    }

    .header__menu-toggle {
        display: none;
    }
    
    .header__logo {
        flex: 0;
        justify-content: flex-start;
    }

    /* Theme Toggle - Tablet */
    .theme-toggle {
        margin-left: var(--spacing-lg);
    }

    /* Navigation - Tablet */
    .nav {
        position: static;
        width: auto;
        max-width: none;
        height: auto;
        background-color: transparent;
        box-shadow: none;
        padding: 0;
        overflow: visible;
        transform: translateX(0);
    }

    .nav__list {
        flex-direction: row;
        align-items: center;
        gap: var(--spacing-xs);
    }

    .nav__item {
        width: auto;
    }

    .nav__link {
        padding: var(--spacing-sm) var(--spacing-md);
        font-size: var(--font-size-sm);
    }

    .nav__link--cta {
        margin-top: 0;
        margin-left: var(--spacing-sm);
    }

    /* Breadcrumb */
    .breadcrumb {
        padding: var(--spacing-md) var(--spacing-xl);
    }

    /* Footer */
    .footer__container {
        padding: var(--spacing-2xl) var(--spacing-xl) var(--spacing-md);
    }

    .footer__grid {
        grid-template-columns: 2fr 1fr 1fr 1fr;
        gap: var(--spacing-xl);
    }
}

/* ===================================
   DESKTOP STYLES (min-width: 1024px)
   =================================== */
@media (min-width: 1024px) {
    :root {
        --font-size-4xl: 48px;
        --font-size-5xl: 64px;
    }

    /* Header */
    .header__container {
        padding: var(--spacing-lg) var(--spacing-2xl);
    }

    .nav__list {
        gap: var(--spacing-md);
    }

    .nav__link {
        padding: var(--spacing-md) var(--spacing-lg);
        font-size: var(--font-size-base);
    }

    .nav__link--cta {
        margin-left: var(--spacing-md);
    }

    /* Breadcrumb */
    .breadcrumb {
        padding: var(--spacing-md) var(--spacing-2xl);
    }

    /* Footer */
    .footer__container {
        padding: var(--spacing-3xl) var(--spacing-2xl) var(--spacing-md);
    }

    .container {
        padding: 0 var(--spacing-2xl);
    }
}

/* ===================================
   LARGE DESKTOP (min-width: 1440px)
   =================================== */
@media (min-width: 1440px) {
    .header__container,
    .footer__container {
        padding-left: var(--spacing-3xl);
        padding-right: var(--spacing-3xl);
    }

    .breadcrumb {
        padding: var(--spacing-md) var(--spacing-3xl);
    }
}

/* ===================================
   ACCESSIBILITY
   =================================== */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
        scroll-behavior: auto !important;
    }
}

/* High contrast mode */
@media (prefers-contrast: high) {
    :root {
        --color-border: #000000;
    }
    
    .nav__link:hover,
    .nav__link--active {
        outline: 2px solid currentColor;
    }
}

/* Dark mode enhancements */
html[data-theme="dark"] .header {
    box-shadow: 0 1px 0 rgba(255, 255, 255, 0.1);
}

html[data-theme="dark"] .footer {
    background-color: #0a0a0a;
    border-top: 1px solid var(--color-border);
}

html[data-theme="dark"] .breadcrumb {
    background-color: var(--color-bg-primary);
}

/* Print styles */
@media print {
    .header,
    .nav,
    .breadcrumb,
    .footer,
    .share__buttons,
    .code-block__copy {
        display: none !important;
    }

    body {
        font-size: 12pt;
    }

    a {
        text-decoration: underline;
    }

    img {
        max-width: 100% !important;
    }
}