/* =================================
   DESIGN SYSTEM & CSS VARIABLES
   ================================= */

:root {
    /* Colors */
    --color-bg: #000000;
    --color-text: #FFFFFF;
    --color-accent: #FF6B00;
    --color-gray: #808080;
    --color-gray-light: #999999;
    
    /* Typography */
    --font-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-weight-regular: 400;
    --font-weight-semibold: 600;
    --font-weight-bold: 700;
    --font-weight-extrabold: 800;
    --font-weight-black: 900;
    
    /* Spacing */
    --spacing-xs: 8px;
    --spacing-sm: 16px;
    --spacing-md: 24px;
    --spacing-lg: 32px;
    --spacing-xl: 48px;
    --spacing-2xl: 64px;
    --spacing-3xl: 80px;
    --spacing-4xl: 120px;
    
    /* Border Radius */
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
    
    /* Transitions */
    --transition-fast: 0.15s ease;
    --transition-normal: 0.3s ease;
    --transition-slow: 0.5s ease;
    
    /* Shadows */
    --shadow-sm: 0 2px 8px rgba(255, 107, 0, 0.2);
    --shadow-md: 0 4px 16px rgba(255, 107, 0, 0.3);
    --shadow-lg: 0 8px 32px rgba(255, 107, 0, 0.4);
    
    /* Z-index */
    --z-navbar: 1000;
    --z-modal: 2000;
}

/* =================================
   RESET & BASE STYLES
   ================================= */

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

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

body {
    font-family: var(--font-primary);
    background-color: var(--color-bg);
    color: var(--color-text);
    line-height: 1.6;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* =================================
   TYPOGRAPHY
   ================================= */

h1, h2, h3, h4, h5, h6 {
    font-weight: var(--font-weight-bold);
    line-height: 1.2;
}

p {
    line-height: 1.6;
}

.accent-text {
    color: var(--color-accent);
}

/* =================================
   LAYOUT CONTAINERS
   ================================= */

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

@media (min-width: 768px) {
    .container {
        padding: 0 var(--spacing-xl);
    }
}

/* =================================
   NAVIGATION
   ================================= */

.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background-color: rgba(0, 0, 0, 0.95);
    backdrop-filter: blur(10px);
    z-index: var(--z-navbar);
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    transition: background-color var(--transition-normal);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--spacing-md);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-logo a {
    font-size: 0.875rem;
    font-weight: var(--font-weight-bold);
    color: var(--color-text);
    text-decoration: none;
    letter-spacing: 0.05em;
    transition: color var(--transition-fast);
}

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

.nav-menu {
    display: none;
    list-style: none;
    gap: var(--spacing-lg);
}

@media (min-width: 768px) {
    .nav-menu {
        display: flex;
    }
}

.nav-link {
    color: var(--color-text);
    text-decoration: none;
    font-weight: var(--font-weight-semibold);
    font-size: 0.9375rem;
    transition: color var(--transition-fast);
    position: relative;
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background-color: var(--color-accent);
    transition: width var(--transition-normal);
}

.nav-link:hover,
.nav-link.active {
    color: var(--color-accent);
}

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

.mobile-menu-toggle {
    display: flex;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: var(--spacing-xs);
}

@media (min-width: 768px) {
    .mobile-menu-toggle {
        display: none;
    }
}

.mobile-menu-toggle span {
    width: 24px;
    height: 2px;
    background-color: var(--color-text);
    transition: all var(--transition-normal);
}

/* Mobile menu active state */
.mobile-menu-toggle.active span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
}

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

.mobile-menu-toggle.active span:nth-child(3) {
    transform: rotate(-45deg) translate(7px, -6px);
}

/* Mobile menu dropdown */
@media (max-width: 767px) {
    .nav-menu {
        display: none;
        position: fixed;
        top: 60px;
        left: 0;
        right: 0;
        background-color: rgba(0, 0, 0, 0.98);
        flex-direction: column;
        padding: var(--spacing-lg);
        gap: var(--spacing-md);
        border-bottom: 1px solid rgba(255, 255, 255, 0.1);
        max-height: 0;
        overflow: hidden;
        transition: max-height var(--transition-normal);
    }
    
    .nav-menu.mobile-active {
        display: flex;
        max-height: 400px;
    }
    
    .nav-link {
        padding: var(--spacing-sm);
        text-align: center;
        font-size: 1.125rem;
    }
}

/* =================================
   HERO SECTION
   ================================= */

.hero-section {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-4xl) 0;
    margin-top: 60px;
}

.hero-content {
    text-align: center;
    max-width: 900px;
    margin: 0 auto;
}

.hero-title {
    font-size: clamp(2.5rem, 8vw, 5rem);
    font-weight: var(--font-weight-black);
    line-height: 1.1;
    letter-spacing: -0.02em;
    margin-bottom: var(--spacing-lg);
}

.hero-subtitle {
    font-size: clamp(1.125rem, 3vw, 1.5rem);
    font-weight: var(--font-weight-regular);
    color: var(--color-gray-light);
    margin-bottom: var(--spacing-2xl);
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

/* =================================
   THESIS SECTION
   ================================= */

.thesis-section {
    padding: var(--spacing-4xl) 0;
    background-color: var(--color-bg);
}

.thesis-content {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-2xl);
}

@media (min-width: 768px) {
    .thesis-content {
        gap: var(--spacing-3xl);
    }
}

.thesis-statement {
    text-align: center;
}

.thesis-text {
    font-size: clamp(1.5rem, 4vw, 2.5rem);
    font-weight: var(--font-weight-bold);
    line-height: 1.3;
    letter-spacing: -0.01em;
}

/* =================================
   AUDIENCE SECTION
   ================================= */

.audience-section {
    padding: var(--spacing-3xl) 0;
}

.section-label {
    font-size: 0.875rem;
    font-weight: var(--font-weight-bold);
    color: var(--color-accent);
    letter-spacing: 0.1em;
    text-align: center;
    margin-bottom: var(--spacing-2xl);
}

.audience-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--spacing-lg);
}

@media (min-width: 768px) {
    .audience-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: var(--spacing-xl);
    }
}

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

.audience-card {
    padding: var(--spacing-xl);
    border: 2px solid rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-md);
    transition: all var(--transition-normal);
}

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

.audience-title {
    font-size: 1.125rem;
    font-weight: var(--font-weight-bold);
    margin-bottom: var(--spacing-md);
    letter-spacing: 0.05em;
}

.audience-description {
    font-size: 0.9375rem;
    color: var(--color-gray-light);
    line-height: 1.6;
}

/* =================================
   CHAPTERS SECTION
   ================================= */

.chapters-section {
    padding: var(--spacing-3xl) 0;
}

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

@media (min-width: 768px) {
    .chapters-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: var(--spacing-2xl);
    }
}

.chapters-column {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
}

.chapter-item {
    display: flex;
    align-items: flex-start;
    gap: var(--spacing-md);
    padding: var(--spacing-lg);
    border-radius: var(--radius-md);
    transition: all var(--transition-normal);
}

.chapter-item:hover {
    background-color: rgba(255, 255, 255, 0.03);
    transform: translateX(8px);
}

.chapter-number {
    font-size: 1.5rem;
    font-weight: var(--font-weight-extrabold);
    color: var(--color-accent);
    min-width: 60px;
    flex-shrink: 0;
}

.chapter-title {
    font-size: 1.125rem;
    font-weight: var(--font-weight-bold);
    line-height: 1.4;
}

/* =================================
   ANTI-PATTERNS SECTION
   ================================= */

.anti-patterns-section {
    padding: var(--spacing-3xl) 0;
}

.anti-patterns-subtitle {
    text-align: center;
    font-size: 1.25rem;
    color: var(--color-gray-light);
    margin-bottom: var(--spacing-2xl);
}

.anti-patterns-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--spacing-lg);
}

@media (min-width: 768px) {
    .anti-patterns-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: var(--spacing-xl);
    }
}

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

.anti-pattern-card {
    padding: var(--spacing-xl);
    border: 2px solid var(--color-accent);
    border-radius: var(--radius-md);
    transition: all var(--transition-normal);
    cursor: pointer;
}

.anti-pattern-card:hover,
.anti-pattern-card:focus {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-width: 3px;
    outline: none;
}

.anti-pattern-title {
    font-size: 1.25rem;
    font-weight: var(--font-weight-bold);
    margin-bottom: var(--spacing-md);
    color: var(--color-text);
}

.anti-pattern-description {
    font-size: 0.9375rem;
    color: var(--color-gray-light);
    line-height: 1.6;
}

/* =================================
   CTA SECTION
   ================================= */

.cta-section {
    padding: var(--spacing-4xl) 0;
    text-align: center;
}

.cta-content {
    max-width: 800px;
    margin: 0 auto;
}

.cta-title {
    font-size: clamp(2rem, 6vw, 4rem);
    font-weight: var(--font-weight-black);
    line-height: 1.1;
    letter-spacing: -0.02em;
    margin-bottom: var(--spacing-lg);
}

.cta-subtitle {
    font-size: clamp(1rem, 2.5vw, 1.375rem);
    color: var(--color-gray);
    margin-bottom: var(--spacing-2xl);
}

/* =================================
   BUTTONS
   ================================= */

.cta-button {
    display: inline-block;
    padding: var(--spacing-md) var(--spacing-2xl);
    font-size: 1rem;
    font-weight: var(--font-weight-bold);
    letter-spacing: 0.05em;
    text-transform: uppercase;
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-normal);
    position: relative;
    overflow: hidden;
    min-width: 200px;
}

.cta-button-primary {
    background-color: var(--color-accent);
    color: var(--color-text);
}

.cta-button-primary:hover {
    transform: scale(1.05);
    box-shadow: var(--shadow-lg);
}

.cta-button-primary:active {
    transform: scale(0.98);
}

.cta-button-primary:focus {
    outline: 3px solid rgba(255, 107, 0, 0.5);
    outline-offset: 4px;
}

.cta-button-primary:disabled {
    background-color: var(--color-gray);
    cursor: not-allowed;
    opacity: 0.5;
    transform: none;
}

/* Ripple effect */
.cta-button::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    border-radius: 50%;
    background-color: rgba(255, 255, 255, 0.3);
    transform: translate(-50%, -50%);
    transition: width 0.6s, height 0.6s;
}

.cta-button:active::after {
    width: 300px;
    height: 300px;
}

/* =================================
   FOOTER
   ================================= */

.footer {
    padding: var(--spacing-2xl) 0;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    margin-top: var(--spacing-4xl);
}

.footer-content {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
    text-align: center;
}

@media (min-width: 768px) {
    .footer-content {
        flex-direction: row;
        justify-content: space-between;
        align-items: center;
        text-align: left;
    }
}

.footer-brand p {
    font-size: 0.875rem;
    font-weight: var(--font-weight-bold);
    letter-spacing: 0.05em;
}

.footer-links {
    display: flex;
    gap: var(--spacing-md);
    align-items: center;
    justify-content: center;
    flex-wrap: wrap;
}

.footer-links a {
    color: var(--color-text);
    text-decoration: none;
    font-size: 0.875rem;
    transition: color var(--transition-fast);
}

.footer-links a:hover {
    color: var(--color-accent);
    text-decoration: underline;
}

.footer-separator {
    color: var(--color-gray);
}

.footer-copyright {
    font-size: 0.875rem;
    color: var(--color-gray);
}

/* =================================
   ANIMATIONS
   ================================= */

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes slideInLeft {
    from {
        opacity: 0;
        transform: translateX(-50px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

@keyframes slideInRight {
    from {
        opacity: 0;
        transform: translateX(50px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

.fade-in {
    animation: fadeIn 0.8s ease forwards;
}

.fade-in-delay {
    animation: fadeIn 0.8s ease 0.2s forwards;
    opacity: 0;
}

.fade-in-delay-2 {
    animation: fadeIn 0.8s ease 0.4s forwards;
    opacity: 0;
}

.slide-in-left {
    animation: slideInLeft 0.8s ease forwards;
}

.slide-in-right {
    animation: slideInRight 0.8s ease forwards;
}

/* Intersection Observer animations */
.fade-in-stagger {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-in-stagger.visible {
    opacity: 1;
    transform: translateY(0);
}

/* =================================
   ACCESSIBILITY & REDUCED MOTION
   ================================= */

@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;
    }
}

/* Focus visible for keyboard navigation */
*:focus-visible {
    outline: 3px solid var(--color-accent);
    outline-offset: 2px;
}

/* =================================
   RESPONSIVE BREAKPOINTS
   ================================= */

/* Mobile First - Base styles above */

/* Tablet: 768px and up */
@media (min-width: 768px) {
    :root {
        font-size: 17px;
    }
}

/* Desktop: 1024px and up */
@media (min-width: 1024px) {
    :root {
        font-size: 18px;
    }
}

/* Large Desktop: 1440px and up */
@media (min-width: 1440px) {
    .container {
        max-width: 1280px;
    }
}