/* ========================================
   CSS Variables System
   ======================================== */
:root {
    /* Color System */
    --color-primary: #2563eb;
    --color-primary-light: #3b82f6;
    --color-primary-dark: #1d4ed8;
    --color-secondary: #8b5cf6;
    --color-secondary-light: #a78bfa;
    --color-secondary-dark: #7c3aed;

    --color-success: #10b981;
    --color-warning: #f59e0b;
    --color-error: #ef4444;
    --color-info: #06b6d4;

    /* Neutral Colors */
    --color-white: #ffffff;
    --color-black: #000000;
    --color-gray-50: #f9fafb;
    --color-gray-100: #f3f4f6;
    --color-gray-200: #e5e7eb;
    --color-gray-300: #d1d5db;
    --color-gray-400: #9ca3af;
    --color-gray-500: #6b7280;
    --color-gray-600: #4b5563;
    --color-gray-700: #374151;
    --color-gray-800: #1f2937;
    --color-gray-900: #111827;

    /* Text Colors */
    --color-text-primary: var(--color-gray-900);
    --color-text-secondary: var(--color-gray-600);
    --color-text-muted: var(--color-gray-500);
    --color-text-light: var(--color-gray-400);

    /* Background Colors */
    --color-bg-primary: var(--color-white);
    --color-bg-secondary: var(--color-gray-50);
    --color-bg-muted: var(--color-gray-100);
    --color-bg-dark: var(--color-gray-900);

    /* Border Colors */
    --color-border-light: var(--color-gray-200);
    --color-border-medium: var(--color-gray-300);
    --color-border-dark: var(--color-gray-400);

    /* Spacing System */
    --spacing-xs: 0.25rem;    /* 4px */
    --spacing-sm: 0.5rem;     /* 8px */
    --spacing-md: 1rem;       /* 16px */
    --spacing-lg: 1.5rem;     /* 24px */
    --spacing-xl: 2rem;       /* 32px */
    --spacing-2xl: 2.5rem;    /* 40px */
    --spacing-3xl: 3rem;      /* 48px */
    --spacing-4xl: 4rem;      /* 64px */
    --spacing-5xl: 5rem;      /* 80px */

    /* Typography */
    --font-family-base: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    --font-family-heading: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    --font-family-mono: 'Courier New', Courier, monospace;

    --font-size-xs: 0.75rem;    /* 12px */
    --font-size-sm: 0.875rem;   /* 14px */
    --font-size-base: 1rem;     /* 16px */
    --font-size-lg: 1.125rem;   /* 18px */
    --font-size-xl: 1.25rem;    /* 20px */
    --font-size-2xl: 1.5rem;    /* 24px */
    --font-size-3xl: 1.875rem;  /* 30px */
    --font-size-4xl: 2.25rem;   /* 36px */
    --font-size-5xl: 3rem;      /* 48px */

    --font-weight-light: 300;
    --font-weight-normal: 400;
    --font-weight-medium: 500;
    --font-weight-semibold: 600;
    --font-weight-bold: 700;
    --font-weight-extrabold: 800;

    --line-height-tight: 1.25;
    --line-height-normal: 1.5;
    --line-height-relaxed: 1.75;
    --line-height-loose: 2;

    /* Shadows */
    --shadow-xs: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-sm: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px 0 rgba(0, 0, 0, 0.06);
    --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);
    --shadow-2xl: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
    --shadow-inner: inset 0 2px 4px 0 rgba(0, 0, 0, 0.06);

    /* Border Radius */
    --radius-sm: 0.25rem;   /* 4px */
    --radius-md: 0.5rem;     /* 8px */
    --radius-lg: 0.75rem;    /* 12px */
    --radius-xl: 1rem;       /* 16px */
    --radius-2xl: 1.5rem;    /* 24px */
    --radius-full: 9999px;

    /* Transitions */
    --transition-fast: 150ms ease-in-out;
    --transition-base: 200ms ease-in-out;
    --transition-normal: 300ms ease-in-out;
    --transition-slow: 500ms ease-in-out;

    /* Z-index */
    --z-dropdown: 1000;
    --z-sticky: 1020;
    --z-fixed: 1030;
    --z-modal-backdrop: 1040;
    --z-modal: 1050;
    --z-popover: 1060;
    --z-tooltip: 1070;
}

/* ========================================
   Global Reset
   ======================================== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

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

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

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

h1 { font-size: var(--font-size-5xl); }
h2 { font-size: var(--font-size-4xl); }
h3 { font-size: var(--font-size-3xl); }
h4 { font-size: var(--font-size-2xl); }
h5 { font-size: var(--font-size-xl); }
h6 { font-size: var(--font-size-lg); }

p {
    margin-bottom: var(--spacing-md);
}

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

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

/* ========================================
   Utility Classes
   ======================================== */

/* Container */
.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
}

.container-fluid {
    width: 100%;
    padding: 0 var(--spacing-lg);
}

.container-narrow {
    width: 100%;
    max-width: 800px;
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
}

/* Card */
.card {
    background-color: var(--color-bg-primary);
    border: 1px solid var(--color-border-light);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
    box-shadow: var(--shadow-sm);
    transition: box-shadow var(--transition-base), transform var(--transition-base);
}

.card:hover {
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
}

.card-flat {
    box-shadow: none;
    border: none;
}

.card-bordered {
    border-width: 2px;
    border-color: var(--color-border-medium);
}

/* Section Title */
.section-title {
    font-size: var(--font-size-3xl);
    font-weight: var(--font-weight-bold);
    text-align: center;
    margin-bottom: var(--spacing-3xl);
    position: relative;
    padding-bottom: var(--spacing-md);
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 60px;
    height: 4px;
    background: linear-gradient(90deg, var(--color-primary), var(--color-secondary));
    border-radius: var(--radius-full);
}

.section-title-left {
    text-align: left;
}

.section-title-left::after {
    left: 0;
    transform: none;
}

/* Button */
.button {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-sm) var(--spacing-xl);
    font-size: var(--font-size-base);
    font-weight: var(--font-weight-medium);
    line-height: var(--line-height-tight);
    border: 1px solid transparent;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-base);
    text-decoration: none;
    white-space: nowrap;
}

.button:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

.button-primary {
    background-color: var(--color-primary);
    color: var(--color-white);
    border-color: var(--color-primary);
}

.button-primary:hover:not(:disabled) {
    background-color: var(--color-primary-dark);
    border-color: var(--color-primary-dark);
    box-shadow: var(--shadow-md);
}

.button-secondary {
    background-color: var(--color-secondary);
    color: var(--color-white);
    border-color: var(--color-secondary);
}

.button-secondary:hover:not(:disabled) {
    background-color: var(--color-secondary-dark);
    border-color: var(--color-secondary-dark);
    box-shadow: var(--shadow-md);
}

.button-outline {
    background-color: transparent;
    color: var(--color-primary);
    border-color: var(--color-primary);
}

.button-outline:hover:not(:disabled) {
    background-color: var(--color-primary);
    color: var(--color-white);
    box-shadow: var(--shadow-md);
}

.button-ghost {
    background-color: transparent;
    color: var(--color-text-primary);
    border-color: transparent;
}

.button-ghost:hover:not(:disabled) {
    background-color: var(--color-bg-secondary);
}

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

.button-lg {
    padding: var(--spacing-md) var(--spacing-2xl);
    font-size: var(--font-size-lg);
}

/* Flexbox Utilities */
.flex { display: flex; }
.flex-inline { display: inline-flex; }
.flex-row { flex-direction: row; }
.flex-col { flex-direction: column; }
.flex-wrap { flex-wrap: wrap; }
.items-start { align-items: flex-start; }
.items-center { align-items: center; }
.items-end { align-items: flex-end; }
.justify-start { justify-content: flex-start; }
.justify-center { justify-content: center; }
.justify-end { justify-content: flex-end; }
.justify-between { justify-content: space-between; }
.gap-sm { gap: var(--spacing-sm); }
.gap-md { gap: var(--spacing-md); }
.gap-lg { gap: var(--spacing-lg); }

/* Spacing Utilities */
.m-0 { margin: 0; }
.mt-sm { margin-top: var(--spacing-sm); }
.mt-md { margin-top: var(--spacing-md); }
.mt-lg { margin-top: var(--spacing-lg); }
.mb-sm { margin-bottom: var(--spacing-sm); }
.mb-md { margin-bottom: var(--spacing-md); }
.mb-lg { margin-bottom: var(--spacing-lg); }
.ml-sm { margin-left: var(--spacing-sm); }
.ml-md { margin-left: var(--spacing-md); }
.ml-lg { margin-left: var(--spacing-lg); }
.mr-sm { margin-right: var(--spacing-sm); }
.mr-md { margin-right: var(--spacing-md); }
.mr-lg { margin-right: var(--spacing-lg); }

.p-0 { padding: 0; }
.pt-sm { padding-top: var(--spacing-sm); }
.pt-md { padding-top: var(--spacing-md); }
.pt-lg { padding-top: var(--spacing-lg); }
.pb-sm { padding-bottom: var(--spacing-sm); }
.pb-md { padding-bottom: var(--spacing-md); }
.pb-lg { padding-bottom: var(--spacing-lg); }
.pl-sm { padding-left: var(--spacing-sm); }
.pl-md { padding-left: var(--spacing-md); }
.pl-lg { padding-left: var(--spacing-lg); }
.pr-sm { padding-right: var(--spacing-sm); }
.pr-md { padding-right: var(--spacing-md); }
.pr-lg { padding-right: var(--spacing-lg); }

/* Text Utilities */
.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }
.text-primary { color: var(--color-primary); }
.text-secondary { color: var(--color-secondary); }
.text-muted { color: var(--color-text-muted); }
.text-sm { font-size: var(--font-size-sm); }
.text-lg { font-size: var(--font-size-lg); }
.font-bold { font-weight: var(--font-weight-bold); }
.font-medium { font-weight: var(--font-weight-medium); }

/* Display Utilities */
.hidden { display: none; }
.block { display: block; }
.inline-block { display: inline-block; }

/* ========================================
   Welcome Page Styles
   ======================================== */
.welcome-page {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 1000;
    color: var(--color-white);
}

.animated-bg {
    background: linear-gradient(-45deg, #2563eb, #8b5cf6, #06b6d4, #10b981);
    background-size: 400% 400%;
    animation: gradientFlow 15s ease infinite;
}

.welcome-content {
    text-align: center;
    padding: var(--spacing-2xl);
    animation: fadeIn 1s ease-in;
}

.welcome-title {
    font-size: 4rem;
    font-weight: var(--font-weight-bold);
    margin-bottom: var(--spacing-lg);
    text-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
    animation: slideInUp 0.8s ease-out;
}

.welcome-subtitle {
    font-size: 1.5rem;
    font-weight: var(--font-weight-normal);
    margin-bottom: var(--spacing-3xl);
    opacity: 0.9;
    animation: slideInUp 0.8s ease-out 0.2s both;
}

.scroll-hint {
    margin-top: var(--spacing-2xl);
    color: var(--color-white);
    animation: bounce 2s infinite;
}

.scroll-hint svg {
    display: block;
    margin: 0 auto;
    filter: drop-shadow(0 2px 4px rgba(0, 0, 0, 0.2));
}

.main-page {
    min-height: 100vh;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    animation: fadeIn 1s ease-in;
}

/* Welcome Page Transition States */
.welcome-page.fade-out {
    animation: fadeOut 0.8s ease-in-out forwards;
}

.welcome-page.hidden {
    display: none;
}

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

/* Responsive Design for Welcome Page */
@media (max-width: 768px) {
    .welcome-title {
        font-size: 2.5rem;
    }

    .welcome-subtitle {
        font-size: 1.2rem;
    }

    .welcome-content {
        padding: var(--spacing-lg);
    }
}

@media (max-width: 480px) {
    .welcome-title {
        font-size: 2rem;
    }

    .welcome-subtitle {
        font-size: 1rem;
    }

    .scroll-hint svg {
        width: 32px;
        height: 32px;
    }
}

/* ========================================
   Navigation Bar Styles
   ======================================== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background-color: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    box-shadow: var(--shadow-sm);
    z-index: 100;
    transition: all var(--transition-base);
}

.navbar.scrolled {
    box-shadow: var(--shadow-md);
    background-color: rgba(255, 255, 255, 0.98);
}

.nav-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-md) 0;
}

.nav-logo {
    font-size: var(--font-size-xl);
    font-weight: var(--font-weight-bold);
    background: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    text-decoration: none;
    transition: transform var(--transition-base);
}

.nav-logo:hover {
    transform: scale(1.05);
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: var(--spacing-lg);
    margin: 0;
    padding: 0;
}

.nav-link {
    color: var(--color-text-primary);
    text-decoration: none;
    font-size: var(--font-size-base);
    font-weight: var(--font-weight-medium);
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--radius-md);
    transition: all var(--transition-base);
    position: relative;
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 0;
    height: 2px;
    background: linear-gradient(90deg, var(--color-primary), var(--color-secondary));
    transition: width var(--transition-base);
}

.nav-link:hover {
    color: var(--color-primary);
    background-color: var(--color-bg-secondary);
}

.nav-link:hover::after {
    width: 80%;
}

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

.nav-link.active::after {
    width: 80%;
}

.nav-toggle {
    display: none;
    flex-direction: column;
    background: none;
    border: none;
    cursor: pointer;
    padding: var(--spacing-sm);
    gap: 4px;
    z-index: 101;
}

.nav-toggle span {
    display: block;
    width: 25px;
    height: 3px;
    background-color: var(--color-text-primary);
    border-radius: var(--radius-sm);
    transition: all var(--transition-base);
}

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

.nav-toggle.active span:nth-child(2) {
    opacity: 0;
    transform: translateX(-20px);
}

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

/* Mobile Navigation */
@media (max-width: 768px) {
    .nav-toggle {
        display: flex;
    }

    .nav-menu {
        position: fixed;
        top: 0;
        right: -100%;
        width: 70%;
        max-width: 300px;
        height: 100vh;
        background-color: rgba(255, 255, 255, 0.98);
        backdrop-filter: blur(10px);
        -webkit-backdrop-filter: blur(10px);
        flex-direction: column;
        padding: var(--spacing-5xl) var(--spacing-xl);
        gap: 0;
        box-shadow: var(--shadow-xl);
        transition: right var(--transition-normal);
        overflow-y: auto;
    }

    .nav-menu.active {
        right: 0;
    }

    .nav-menu li {
        width: 100%;
        margin-bottom: var(--spacing-md);
    }

    .nav-link {
        display: block;
        width: 100%;
        padding: var(--spacing-md) var(--spacing-lg);
        border-radius: var(--radius-md);
        font-size: var(--font-size-lg);
    }

    .nav-link::after {
        display: none;
    }

    .nav-link:hover {
        background-color: var(--color-bg-secondary);
        transform: translateX(4px);
    }

    /* Overlay for mobile menu */
    .nav-overlay {
        display: none;
        position: fixed;
        top: 0;
        left: 0;
        width: 100%;
        height: 100%;
        background-color: rgba(0, 0, 0, 0.5);
        z-index: 99;
        opacity: 0;
        transition: opacity var(--transition-normal);
    }

    .nav-overlay.active {
        display: block;
        opacity: 1;
    }
}

/* Desktop Navigation Tweaks */
@media (min-width: 769px) {
    .nav-overlay {
        display: none !important;
    }
}

/* ========================================
   Profile Section Styles
   ======================================== */
.profile-section {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding-top: 80px;
    padding-bottom: var(--spacing-2xl);
}

.profile-content {
    text-align: center;
    color: var(--color-white);
}

.profile-avatar {
    margin-bottom: var(--spacing-2xl);
}

.avatar-img {
    width: 150px;
    height: 150px;
    border-radius: 50%;
    object-fit: cover;
    border: 4px solid rgba(255, 255, 255, 0.3);
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.3);
    animation: avatarFloat 3s ease-in-out infinite;
    transition: transform var(--transition-normal);
}

.avatar-img:hover {
    transform: scale(1.05);
}

.profile-name {
    font-size: 4rem;
    font-weight: var(--font-weight-bold);
    margin-bottom: var(--spacing-md);
    background: linear-gradient(135deg, var(--color-white) 0%, rgba(255, 255, 255, 0.7) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    text-shadow: 0 2px 10px rgba(0, 0, 0, 0.2);
}

.profile-title {
    font-size: var(--font-size-2xl);
    font-weight: var(--font-weight-medium);
    color: rgba(255, 255, 255, 0.9);
    margin-bottom: var(--spacing-3xl);
    min-height: 2em;
}

.typing-effect {
    overflow: hidden;
    white-space: nowrap;
    border-right: 3px solid var(--color-white);
    animation: typing 3.5s steps(40, end), blink-caret 0.75s step-end infinite;
}

@keyframes typing {
    from { width: 0 }
    to { width: 100% }
}

@keyframes blink-caret {
    from, to { border-color: transparent }
    50% { border-color: var(--color-white) }
}

.social-links {
    display: flex;
    justify-content: center;
    gap: var(--spacing-xl);
    margin-top: var(--spacing-2xl);
}

.social-link {
    width: 50px;
    height: 50px;
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: rgba(255, 255, 255, 0.1);
    border-radius: 50%;
    color: var(--color-white);
    transition: all var(--transition-base);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.social-link:hover {
    background-color: rgba(255, 255, 255, 0.2);
    transform: translateY(-4px) scale(1.1);
    box-shadow: 0 8px 16px rgba(0, 0, 0, 0.2);
}

.social-link svg {
    width: 24px;
    height: 24px;
}

/* Avatar Float Animation */
@keyframes avatarFloat {
    0%, 100% {
        transform: translateY(0px);
    }
    50% {
        transform: translateY(-10px);
    }
}

/* Responsive Design for Profile Section */
@media (max-width: 768px) {
    .profile-section {
        padding-top: 100px;
        padding-bottom: var(--spacing-xl);
    }

    .profile-name {
        font-size: 2.5rem;
    }

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

    .avatar-img {
        width: 120px;
        height: 120px;
    }

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

    .social-link {
        width: 44px;
        height: 44px;
    }

    .social-link svg {
        width: 20px;
        height: 20px;
    }
}

@media (max-width: 480px) {
    .profile-name {
        font-size: 2rem;
    }

    .avatar-img {
        width: 100px;
        height: 100px;
    }
}