:root {
    --primary: #3aa7ff;
    --primary-hover: #1e90ff;
    --primary-light: rgba(58, 167, 255, 0.1);
    
    --bg-primary: #121212;
    --bg-secondary: #1e1e1e;
    --bg-tertiary: #2a2a2a;
    --text-primary: #ffffff;
    --text-secondary: #cfd8e3;
    --text-muted: #778da9;
    --border-color: #333333;
    --card-shadow: 0 4px 12px rgba(0, 0, 0, 0.5);
    
    --transition-fast: 0.2s ease;
    --transition-normal: 0.3s ease;
    --transition-slow: 0.5s ease;
    
    --header-height: 70px;
    --container-max-width: 1400px;
    --section-padding: 80px;
    
    --radius-sm: 5px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --radius-full: 50%;
}

[data-theme="light"] {
    --bg-primary: #f5f5f5;
    --bg-secondary: #ffffff;
    --bg-tertiary: #e8e8e8;
    --text-primary: #121212;
    --text-secondary: #333333;
    --text-muted: #666666;
    --border-color: #dddddd;
    --card-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

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

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

body {
    font-family: 'Poppins', 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    min-height: 100vh;
    line-height: 1.6;
    transition: background-color var(--transition-normal), color var(--transition-normal);
}

h1, h2, h3, h4, h5, h6 {
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: 1rem;
}

h1 { font-size: clamp(2rem, 5vw, 3.5rem); }
h2 { font-size: clamp(1.5rem, 4vw, 2.5rem); }
h3 { font-size: clamp(1.25rem, 3vw, 1.75rem); }

p {
    margin-bottom: 1rem;
    color: var(--text-secondary);
}

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

a:hover {
    color: var(--primary-hover);
    text-decoration: underline;
}

.container {
    max-width: var(--container-max-width);
    margin: 0 auto;
    padding: 0 20px;
}

header, .main-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px 40px;
    background-color: var(--bg-secondary);
    border-radius: var(--radius-md);
    margin: 20px auto;
    margin-bottom: 50px;
    max-width: 2000px;
    position: relative;
    z-index: 1000;
    box-shadow: var(--card-shadow);
    transition: background-color var(--transition-normal);
}

.main-title, .logo {
    color: var(--primary);
    font-size: 1.5rem;
    font-weight: 800;
    margin: 0;
    text-decoration: none;
}

.logo:hover {
    text-decoration: none;
}

nav ul, .main-nav ul {
    list-style: none;
    display: flex;
    gap: 10px;
    align-items: center;
}

nav ul li a, .main-nav ul li a {
    text-decoration: none;
    color: var(--text-primary);
    font-size: 1rem;
    padding: 10px 20px;
    opacity: 0.7;
    transition: opacity var(--transition-fast), color var(--transition-fast);
    border-radius: var(--radius-sm);
}

nav ul li a:hover, .main-nav ul li a:hover {
    opacity: 1;
    color: var(--primary);
    text-decoration: none;
}

.hamburger {
    display: none;
    flex-direction: column;
    gap: 5px;
    cursor: pointer;
    padding: 10px;
    z-index: 1001;
    background: none;
    border: none;
}

.hamburger span {
    width: 25px;
    height: 3px;
    background-color: var(--text-primary);
    border-radius: 3px;
    transition: var(--transition-normal);
}

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

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

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

.profile-button, .profile-btn {
    font-size: 1.5rem;
    background-color: var(--text-primary);
    color: var(--primary);
    border: none;
    border-radius: var(--radius-full);
    width: 50px;
    height: 50px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background-color var(--transition-normal), transform var(--transition-fast);
    text-decoration: none;
}

.profile-button:hover, .profile-btn:hover {
    background-color: var(--primary);
    color: var(--text-primary);
    transform: scale(1.05);
}

.header-controls {
    display: flex;
    align-items: center;
    gap: 15px;
}

.theme-toggle {
    background: var(--bg-tertiary);
    border: 2px solid var(--border-color);
    border-radius: var(--radius-full);
    width: 50px;
    height: 50px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.3rem;
    transition: var(--transition-normal);
}

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

.theme-toggle .icon-sun {
    display: none;
}

.theme-toggle .icon-moon {
    display: block;
}

[data-theme="light"] .theme-toggle .icon-sun {
    display: block;
}

[data-theme="light"] .theme-toggle .icon-moon {
    display: none;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 12px 24px;
    font-size: 1rem;
    font-weight: 600;
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: var(--transition-normal);
    text-decoration: none;
}

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

.btn-primary:hover {
    background-color: var(--primary-hover);
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(58, 167, 255, 0.4);
}

.btn-secondary {
    background-color: var(--bg-tertiary);
    color: var(--text-primary);
    border: 2px solid var(--border-color);
}

.btn-secondary:hover {
    border-color: var(--primary);
    color: var(--primary);
}

input[type="submit"],
button[type="submit"] {
    width: 100%;
    padding: 14px;
    border: none;
    border-radius: var(--radius-md);
    background-color: var(--primary);
    color: white;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition-normal);
}

input[type="submit"]:hover,
button[type="submit"]:hover {
    background-color: var(--primary-hover);
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(58, 167, 255, 0.4);
}

label {
    display: block;
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-secondary);
    margin-bottom: 8px;
}

input[type="text"],
input[type="email"],
input[type="password"],
input[type="number"],
input[type="tel"],
select,
textarea {
    width: 100%;
    padding: 14px;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    background-color: var(--bg-tertiary);
    color: var(--text-primary);
    font-size: 1rem;
    transition: var(--transition-fast);
}

input:focus,
select:focus,
textarea:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px var(--primary-light);
}

input::placeholder {
    color: var(--text-muted);
}

.card {
    background-color: var(--bg-secondary);
    border-radius: var(--radius-lg);
    padding: 24px;
    border: 1px solid var(--border-color);
    box-shadow: var(--card-shadow);
    transition: var(--transition-normal);
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.3);
    border-color: var(--primary);
}

.profile-menu {
    position: relative;
    display: inline-block;
}

.dropdown {
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    position: absolute;
    right: 0;
    top: 100%;
    margin-top: 10px;
    background-color: var(--bg-secondary);
    border-radius: var(--radius-md);
    min-width: 180px;
    box-shadow: var(--card-shadow);
    border: 1px solid var(--border-color);
    transition: var(--transition-fast);
    z-index: 1000;
    list-style: none;
    padding: 8px 0;
}

.profile-menu:hover .dropdown,
.dropdown.show {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.dropdown li a {
    display: block;
    padding: 12px 20px;
    color: var(--text-primary);
    transition: var(--transition-fast);
}

.dropdown li a:hover {
    background-color: var(--primary-light);
    color: var(--primary);
    text-decoration: none;
}

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

@keyframes slideInLeft {
    from {
        opacity: 0;
        transform: translateX(-30px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

@keyframes slideInRight {
    from {
        opacity: 0;
        transform: translateX(30px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

@keyframes pulse {
    0%, 100% {
        transform: scale(1);
    }
    50% {
        transform: scale(1.05);
    }
}

@keyframes shimmer {
    0% {
        background-position: -200% 0;
    }
    100% {
        background-position: 200% 0;
    }
}

.animate-fade-in {
    animation: fadeIn 0.6s ease forwards;
}

.animate-slide-left {
    animation: slideInLeft 0.6s ease forwards;
}

.animate-slide-right {
    animation: slideInRight 0.6s ease forwards;
}

.delay-1 { animation-delay: 0.1s; }
.delay-2 { animation-delay: 0.2s; }
.delay-3 { animation-delay: 0.3s; }
.delay-4 { animation-delay: 0.4s; }
.delay-5 { animation-delay: 0.5s; }

.skeleton {
    background: linear-gradient(90deg, var(--bg-tertiary) 25%, var(--bg-secondary) 50%, var(--bg-tertiary) 75%);
    background-size: 200% 100%;
    animation: shimmer 1.5s infinite;
    border-radius: var(--radius-md);
}

.toast-container {
    position: fixed;
    top: 20px;
    right: 20px;
    z-index: 9999;
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.toast {
    padding: 16px 24px;
    border-radius: var(--radius-md);
    color: white;
    font-weight: 500;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.3);
    animation: slideInRight 0.3s ease;
    display: flex;
    align-items: center;
    gap: 10px;
    min-width: 280px;
}

.toast-success { background-color: #10b981; }
.toast-error { background-color: #ef4444; }
.toast-warning { background-color: #f59e0b; }
.toast-info { background-color: var(--primary); }

.toast-close {
    margin-left: auto;
    background: none;
    border: none;
    color: white;
    cursor: pointer;
    font-size: 1.2rem;
    opacity: 0.7;
    transition: opacity var(--transition-fast);
}

.toast-close:hover { opacity: 1; }

.spinner {
    width: 40px;
    height: 40px;
    border: 3px solid var(--bg-tertiary);
    border-top-color: var(--primary);
    border-radius: var(--radius-full);
    animation: spin 0.8s linear infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.7);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 9999;
    opacity: 0;
    visibility: hidden;
    transition: var(--transition-fast);
}

.loading-overlay.show {
    opacity: 1;
    visibility: visible;
}

footer {
    background-color: var(--bg-secondary);
    padding: 40px 20px;
    margin-top: 80px;
    border-top: 1px solid var(--border-color);
}

.footer-content {
    max-width: var(--container-max-width);
    margin: 0 auto;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 40px;
}

.footer-section h4 {
    color: var(--primary);
    margin-bottom: 20px;
}

.footer-section ul { list-style: none; }
.footer-section ul li { margin-bottom: 10px; }
.footer-section ul li a {
    color: var(--text-secondary);
    transition: color var(--transition-fast);
}
.footer-section ul li a:hover { color: var(--primary); }

.footer-bottom {
    text-align: center;
    padding-top: 30px;
    margin-top: 30px;
    border-top: 1px solid var(--border-color);
    color: var(--text-muted);
}

.social-links {
    display: flex;
    gap: 15px;
}

.social-links a {
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: var(--bg-tertiary);
    border-radius: var(--radius-full);
    color: var(--text-primary);
    transition: var(--transition-normal);
}

.social-links a:hover {
    background-color: var(--primary);
    color: white;
    transform: translateY(-3px);
}

@media screen and (max-width: 1024px) {
    header, .main-header {
        padding: 15px 25px;
        margin: 15px;
    }
    nav ul li a, .main-nav ul li a {
        font-size: 0.9rem;
        padding: 8px 15px;
    }
    .container { padding: 0 15px; }
}

@media screen and (max-width: 768px) {
    :root { --section-padding: 40px; }
    
    header, .main-header {
        padding: 12px 20px;
        margin: 10px;
        flex-wrap: wrap;
    }
    
    .main-title, .logo { font-size: 1.2rem; }
    .hamburger { display: flex; }
    
    nav, .main-nav {
        position: fixed;
        top: 0;
        right: -100%;
        width: 70%;
        max-width: 300px;
        height: 100vh;
        background-color: var(--bg-secondary);
        padding: 80px 20px 20px;
        transition: right var(--transition-normal);
        z-index: 999;
        box-shadow: -5px 0 15px rgba(0, 0, 0, 0.3);
    }
    
    nav.active, .main-nav.active { right: 0; }
    nav ul, .main-nav ul { flex-direction: column; gap: 5px; }
    nav ul li, .main-nav ul li { width: 100%; }
    nav ul li a, .main-nav ul li a {
        display: block;
        padding: 15px 20px;
        font-size: 1.1rem;
        border-radius: var(--radius-md);
    }
    nav ul li a:hover, .main-nav ul li a:hover { background-color: var(--primary-light); }
    
    .nav-overlay {
        position: fixed;
        top: 0;
        left: 0;
        width: 100%;
        height: 100%;
        background-color: rgba(0, 0, 0, 0.5);
        opacity: 0;
        visibility: hidden;
        transition: var(--transition-normal);
        z-index: 998;
    }
    
    .nav-overlay.active {
        opacity: 1;
        visibility: visible;
    }
    
    .profile-button, .profile-btn { width: 40px; height: 40px; font-size: 1.2rem; }
    .theme-toggle { width: 40px; height: 40px; font-size: 1.1rem; }
    .card { padding: 16px; }
    .footer-content { grid-template-columns: 1fr; text-align: center; }
    .social-links { justify-content: center; }
    .toast-container { left: 10px; right: 10px; }
    .toast { min-width: auto; }
}

@media screen and (max-width: 480px) {
    html { font-size: 14px; }
    header, .main-header { padding: 10px 15px; }
    .main-title, .logo { font-size: 1rem; }
    nav, .main-nav { width: 85%; }
    .header-controls { gap: 10px; }
    .profile-button, .profile-btn, .theme-toggle { width: 36px; height: 36px; font-size: 1rem; }
    input[type="text"], input[type="email"], input[type="password"], input[type="number"] { padding: 12px; }
}

.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }
.text-primary { color: var(--primary); }
.text-muted { color: var(--text-muted); }
.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }
.mt-4 { margin-top: 2rem; }
.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }
.mb-4 { margin-bottom: 2rem; }
.p-1 { padding: 0.5rem; }
.p-2 { padding: 1rem; }
.p-3 { padding: 1.5rem; }
.p-4 { padding: 2rem; }
.flex { display: flex; }
.flex-center { display: flex; align-items: center; justify-content: center; }
.flex-between { display: flex; align-items: center; justify-content: space-between; }
.hidden { display: none !important; }
.visible { display: block !important; }

.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    border: 0;
}

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

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