/* ================================
   CSS VARIABLES - COLOR PALETTE FROM LOGO
   ================================ */

:root {
    /* Primary Colors from Logo */
    --color-navy: #2C3E50;
    --color-teal: #3498A2;
    --color-coral: #E74C3C;

    /* Light Mode Colors */
    --bg-primary: #FFFFFF;
    --bg-secondary: #F5F7FA;
    --bg-tertiary: #ECF0F1;
    --text-primary: #1A2332;
    --text-secondary: #5A6C7D;
    --text-tertiary: #95A5A6;

    /* Accent Colors */
    --accent-primary: var(--color-teal);
    --accent-secondary: var(--color-coral);
    --accent-hover: #2980B9;

    /* UI Colors */
    --border-color: #E1E8ED;
    --shadow-color: rgba(0, 0, 0, 0.1);
    --overlay-color: rgba(0, 0, 0, 0.5);

    /* Sidebar */
    --sidebar-bg: var(--color-navy);
    --sidebar-text: #FFFFFF;
    --sidebar-hover: rgba(52, 152, 162, 0.2);
    --sidebar-active: var(--color-teal);

    /* Spacing */
    --sidebar-width: 280px;
    --header-height: 70px;
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;

    /* Typography */
    --font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    --font-size-base: 16px;
    --font-size-sm: 0.875rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.5rem;
    --font-size-2xl: 2rem;
    --font-size-3xl: 2.5rem;

    /* Transitions */
    --transition-fast: 0.15s ease;
    --transition-normal: 0.3s ease;
    --transition-slow: 0.5s ease;
}

/* Dark Mode Variables */
body.dark-mode {
    --bg-primary: #1A1A2E;
    --bg-secondary: #16213E;
    --bg-tertiary: #0F1624;
    --text-primary: #EAEAEA;
    --text-secondary: #B8C1CC;
    --text-tertiary: #8A92A0;

    --border-color: #2D3748;
    --shadow-color: rgba(0, 0, 0, 0.3);

    --sidebar-bg: #0F1624;
    --sidebar-hover: rgba(52, 152, 162, 0.3);
}

/* ================================
   GLOBAL STYLES
   ================================ */

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

html {
    font-size: var(--font-size-base);
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family);
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    transition: background-color var(--transition-normal), color var(--transition-normal);
}

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

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

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

.sidebar {
    position: fixed;
    left: 0;
    top: 0;
    width: var(--sidebar-width);
    height: 100vh;
    background: linear-gradient(180deg, #FFFFFF 0%, #F8F9FA 100%);
    color: var(--color-navy);
    padding: 0;
    display: flex;
    flex-direction: column;
    z-index: 1000;
    transition: transform var(--transition-normal), background-color var(--transition-normal);
    box-shadow: 2px 0 10px rgba(0, 0, 0, 0.05);
}

body.dark-mode .sidebar {
    background: linear-gradient(180deg, #1A1A2E 0%, #0F1624 100%);
    color: var(--sidebar-text);
    box-shadow: 2px 0 10px rgba(0, 0, 0, 0.3);
}

.logo-container {
    margin-bottom: var(--spacing-lg);
    text-align: center;
    padding: var(--spacing-xl) var(--spacing-md) var(--spacing-md);
    border-bottom: 1px solid rgba(44, 62, 80, 0.08);
}

body.dark-mode .logo-container {
    border-bottom-color: rgba(255, 255, 255, 0.08);
}

.logo {
    width: 100%;
    max-width: 180px;
    height: auto;
    margin: 0 auto;
}

.main-nav {
    flex: 1;
    padding: var(--spacing-md) var(--spacing-sm);
}

.main-nav ul {
    list-style: none;
}

.main-nav li {
    margin-bottom: 0.25rem;
}

.nav-link {
    display: flex;
    align-items: center;
    padding: 0.75rem 1.25rem;
    color: var(--color-navy);
    border-radius: 10px;
    transition: all var(--transition-fast);
    font-size: 0.95rem;
    letter-spacing: 0.3px;
    font-weight: 500;
    position: relative;
}

body.dark-mode .nav-link {
    color: #E0E0E0;
}

.nav-link i {
    margin-right: 0.875rem;
    font-size: 1.1rem;
    width: 22px;
    text-align: center;
    opacity: 0.9;
    transition: all var(--transition-fast);
    display: inline-block;
}

.nav-link:hover {
    background-color: rgba(52, 152, 162, 0.08);
    color: var(--color-teal);
    transform: translateX(3px);
}

.nav-link:hover i {
    opacity: 1;
}

body.dark-mode .nav-link:hover {
    background-color: rgba(52, 152, 162, 0.15);
}

.nav-link.active {
    background: linear-gradient(135deg, var(--color-teal) 0%, #2980B9 100%);
    color: white;
    font-weight: 600;
    box-shadow: 0 2px 8px rgba(52, 152, 162, 0.3);
}

.nav-link.active i {
    opacity: 1;
    color: white;
}

.nav-link.active::before {
    content: '';
    position: absolute;
    left: 0;
    top: 50%;
    transform: translateY(-50%);
    width: 4px;
    height: 60%;
    background-color: var(--color-coral);
    border-radius: 0 4px 4px 0;
}

/* Colorful Icon Gradients */
.icon-gradient-1 {
    background: linear-gradient(135deg, #3498A2 0%, #2980B9 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.icon-gradient-2 {
    background: linear-gradient(135deg, #E74C3C 0%, #C0392B 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.icon-gradient-3 {
    background: linear-gradient(135deg, #F39C12 0%, #E67E22 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.icon-gradient-4 {
    background: linear-gradient(135deg, #9B59B6 0%, #8E44AD 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.icon-gradient-5 {
    background: linear-gradient(135deg, #1ABC9C 0%, #16A085 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.icon-gradient-6 {
    background: linear-gradient(135deg, #3498DB 0%, #2C3E50 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.icon-gradient-7 {
    background: linear-gradient(135deg, #E67E22 0%, #D35400 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.icon-gradient-8 {
    background: linear-gradient(135deg, #27AE60 0%, #229954 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.icon-gradient-9 {
    background: linear-gradient(135deg, #8E44AD 0%, #9B59B6 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* Active state - icons turn white */
.nav-link.active i {
    background: none !important;
    -webkit-text-fill-color: white !important;
    color: white !important;
}

/* Hover state - enhance gradient effect */
.nav-link:hover .icon-gradient-1,
.nav-link:hover .icon-gradient-2,
.nav-link:hover .icon-gradient-3,
.nav-link:hover .icon-gradient-4,
.nav-link:hover .icon-gradient-5,
.nav-link:hover .icon-gradient-6,
.nav-link:hover .icon-gradient-7,
.nav-link:hover .icon-gradient-8,
.nav-link:hover .icon-gradient-9 {
    transform: scale(1.15);
    filter: brightness(1.2);
}

/* Theme Toggle */
.theme-toggle {
    margin-top: auto;
    padding: var(--spacing-md) var(--spacing-sm) var(--spacing-lg);
    border-top: 1px solid rgba(44, 62, 80, 0.08);
}

body.dark-mode .theme-toggle {
    border-top-color: rgba(255, 255, 255, 0.08);
}

.theme-toggle-btn {
    width: 100%;
    padding: 0.875rem 1.25rem;
    background: linear-gradient(135deg, rgba(52, 152, 162, 0.1) 0%, rgba(41, 128, 185, 0.1) 100%);
    border: 1px solid rgba(52, 152, 162, 0.2);
    border-radius: 10px;
    color: var(--color-navy);
    font-size: 0.95rem;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-fast);
    display: flex;
    align-items: center;
    justify-content: center;
}

body.dark-mode .theme-toggle-btn {
    color: #E0E0E0;
    background: linear-gradient(135deg, rgba(52, 152, 162, 0.15) 0%, rgba(41, 128, 185, 0.15) 100%);
    border-color: rgba(52, 152, 162, 0.3);
}

.theme-toggle-btn:hover {
    background: linear-gradient(135deg, var(--color-coral) 0%, #C0392B 100%);
    border-color: var(--color-coral);
    color: white;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(231, 76, 60, 0.3);
}

.theme-toggle-btn i {
    margin-right: 0.625rem;
    font-size: 1rem;
}

/* Mobile Menu Toggle */
.mobile-menu-toggle {
    display: none;
    position: fixed;
    top: var(--spacing-md);
    left: var(--spacing-md);
    z-index: 1001;
    background: white;
    color: var(--color-navy);
    border: 1px solid rgba(44, 62, 80, 0.1);
    padding: 0.75rem 1rem;
    border-radius: 10px;
    font-size: 1.25rem;
    cursor: pointer;
    transition: all var(--transition-fast);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

body.dark-mode .mobile-menu-toggle {
    background: var(--bg-secondary);
    color: var(--text-primary);
    border-color: rgba(255, 255, 255, 0.1);
}

.mobile-menu-toggle:hover {
    background: linear-gradient(135deg, var(--color-teal) 0%, #2980B9 100%);
    color: white;
    border-color: var(--color-teal);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(52, 152, 162, 0.3);
}

/* ================================
   MAIN CONTENT AREA
   ================================ */

.main-content {
    margin-left: var(--sidebar-width);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* ================================
   CONTENT SECTIONS
   ================================ */

.content-wrapper {
    flex: 1;
    padding: var(--spacing-xl);
    max-width: 1400px;
    margin: 0 auto;
    width: 100%;
}

.page-title {
    font-size: var(--font-size-3xl);
    color: var(--color-navy);
    margin-bottom: var(--spacing-lg);
    font-weight: 700;
    letter-spacing: -0.5px;
    position: relative;
    display: inline-block;
}

.page-title::after {
    content: '';
    position: absolute;
    bottom: -8px;
    left: 0;
    width: 60px;
    height: 4px;
    background: linear-gradient(90deg, var(--color-teal) 0%, var(--color-coral) 100%);
    border-radius: 2px;
}

body.dark-mode .page-title {
    color: var(--text-primary);
}

.section {
    background-color: var(--bg-secondary);
    padding: var(--spacing-xl);
    border-radius: 16px;
    margin-bottom: var(--spacing-lg);
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.05);
    border: 1px solid rgba(44, 62, 80, 0.05);
    transition: all var(--transition-normal);
}

body.dark-mode .section {
    border-color: rgba(255, 255, 255, 0.05);
}

.section:hover {
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
    transform: translateY(-2px);
}

.section-title {
    font-size: var(--font-size-2xl);
    color: var(--color-teal);
    margin-bottom: var(--spacing-md);
    font-weight: 600;
    position: relative;
    display: inline-block;
}

.section-title::before {
    content: '';
    position: absolute;
    left: -20px;
    top: 50%;
    transform: translateY(-50%);
    width: 4px;
    height: 24px;
    background: linear-gradient(180deg, var(--color-teal) 0%, var(--color-coral) 100%);
    border-radius: 2px;
}

.section-content {
    color: var(--text-secondary);
    line-height: 1.8;
}

/* About Section */
.about-section {
    background: linear-gradient(135deg, rgba(52, 152, 162, 0.05) 0%, rgba(41, 128, 185, 0.05) 100%);
    padding: var(--spacing-xl);
    border-radius: 16px;
    margin-bottom: var(--spacing-lg);
    border: 1px solid rgba(52, 152, 162, 0.1);
    position: relative;
    overflow: hidden;
}

.about-section::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 3px;
    background: linear-gradient(90deg, var(--color-teal) 0%, var(--color-coral) 100%);
}

body.dark-mode .about-section {
    background: linear-gradient(135deg, rgba(52, 152, 162, 0.08) 0%, rgba(41, 128, 185, 0.08) 100%);
    border-color: rgba(52, 152, 162, 0.15);
}

.about-content {
    display: flex;
    gap: var(--spacing-xl);
    align-items: center;
}

.about-text h2 {
    font-size: var(--font-size-2xl);
    color: var(--color-navy);
    margin-bottom: var(--spacing-md);
    font-weight: 700;
}

body.dark-mode .about-text h2 {
    color: var(--text-primary);
}

.about-text p {
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: var(--spacing-sm);
    font-size: 1rem;
}

/* Tab Navigation */
.tab-navigation {
    display: flex;
    gap: 0.5rem;
    margin-bottom: var(--spacing-lg);
    border-bottom: 1px solid var(--border-color);
    flex-wrap: wrap;
}

.tab-btn {
    padding: 0.875rem 1.5rem;
    background-color: transparent;
    border: none;
    color: var(--text-secondary);
    font-size: 0.95rem;
    cursor: pointer;
    transition: all var(--transition-fast);
    border-bottom: 2px solid transparent;
    font-weight: 500;
    position: relative;
    letter-spacing: 0.2px;
}

.tab-btn i {
    margin-right: 0.5rem;
    font-size: 0.9rem;
}

.tab-btn:hover {
    color: var(--color-teal);
    background-color: rgba(52, 152, 162, 0.05);
}

.tab-btn.active {
    color: var(--color-teal);
    border-bottom-color: var(--color-teal);
    font-weight: 600;
    background: linear-gradient(180deg, rgba(52, 152, 162, 0.08) 0%, transparent 100%);
}

.tab-btn.active::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 2px;
    background: linear-gradient(90deg, var(--color-teal) 0%, var(--color-coral) 100%);
}

.tab-content {
    display: none;
    animation: fadeIn var(--transition-normal);
}

.tab-content.active {
    display: block;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Cards */
.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: var(--spacing-lg);
    margin-top: var(--spacing-lg);
}

.card {
    background-color: var(--bg-primary);
    padding: var(--spacing-lg);
    border-radius: 14px;
    border: 1px solid var(--border-color);
    transition: all var(--transition-fast);
    position: relative;
    overflow: hidden;
}

.card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 3px;
    background: linear-gradient(90deg, var(--color-teal) 0%, var(--color-coral) 100%);
    opacity: 0;
    transition: opacity var(--transition-fast);
}

.card:hover {
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.08);
    transform: translateY(-4px);
    border-color: var(--color-teal);
}

.card:hover::before {
    opacity: 1;
}

.card h3 {
    color: var(--color-navy);
    margin-bottom: var(--spacing-sm);
    font-size: var(--font-size-xl);
    font-weight: 600;
}

body.dark-mode .card h3 {
    color: var(--text-primary);
}

.card p {
    color: var(--text-secondary);
    line-height: 1.6;
    font-size: 0.95rem;
}

.card-meta {
    display: flex;
    gap: var(--spacing-md);
    margin-top: var(--spacing-md);
    color: var(--text-tertiary);
    font-size: 0.875rem;
}

.card-meta i {
    color: var(--color-teal);
    margin-right: 0.25rem;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 0.875rem 1.75rem;
    background: linear-gradient(135deg, var(--color-teal) 0%, #2980B9 100%);
    color: white;
    border: none;
    border-radius: 10px;
    font-size: 0.95rem;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-fast);
    box-shadow: 0 2px 8px rgba(52, 152, 162, 0.2);
    letter-spacing: 0.3px;
}

.btn:hover {
    background: linear-gradient(135deg, #2980B9 0%, var(--color-teal) 100%);
    transform: translateY(-2px);
    box-shadow: 0 6px 16px rgba(52, 152, 162, 0.35);
}

.btn-secondary {
    background: linear-gradient(135deg, var(--color-coral) 0%, #C0392B 100%);
    box-shadow: 0 2px 8px rgba(231, 76, 60, 0.2);
}

.btn-secondary:hover {
    background: linear-gradient(135deg, #C0392B 0%, var(--color-coral) 100%);
    box-shadow: 0 6px 16px rgba(231, 76, 60, 0.35);
}

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

.site-footer {
    background: linear-gradient(135deg, var(--color-navy) 0%, #1A2332 100%);
    color: #E0E0E0;
    padding: var(--spacing-xl) var(--spacing-lg);
    margin-top: auto;
    position: relative;
}

.site-footer::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: linear-gradient(90deg, var(--color-teal) 0%, var(--color-coral) 100%);
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-xl);
    max-width: 1200px;
    margin: 0 auto var(--spacing-lg);
}

.footer-section h3 {
    font-size: var(--font-size-lg);
    margin-bottom: var(--spacing-md);
    color: white;
    font-weight: 600;
    letter-spacing: 0.3px;
}

.footer-section p {
    color: rgba(255, 255, 255, 0.7);
    line-height: 1.6;
    font-size: 0.95rem;
}

.footer-links {
    list-style: none;
}

.footer-links li {
    margin-bottom: var(--spacing-sm);
}

.footer-links a {
    color: rgba(255, 255, 255, 0.8);
    transition: all var(--transition-fast);
    font-size: 0.95rem;
    display: inline-block;
}

.footer-links a:hover {
    color: var(--color-coral);
    transform: translateX(3px);
}

.social-links {
    display: flex;
    gap: var(--spacing-sm);
}

.social-links a {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    background: rgba(255, 255, 255, 0.08);
    border: 1px solid rgba(255, 255, 255, 0.15);
    border-radius: 10px;
    color: rgba(255, 255, 255, 0.9);
    font-size: 1.1rem;
    transition: all var(--transition-fast);
}

.social-links a:hover {
    background: linear-gradient(135deg, var(--color-coral) 0%, #C0392B 100%);
    border-color: var(--color-coral);
    color: white;
    transform: translateY(-3px);
    box-shadow: 0 4px 12px rgba(231, 76, 60, 0.4);
}

.footer-bottom {
    text-align: center;
    padding-top: var(--spacing-lg);
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    color: rgba(255, 255, 255, 0.6);
    font-size: 0.9rem;
}

/* ================================
   RESPONSIVE DESIGN
   ================================ */

@media (max-width: 1024px) {
    :root {
        --sidebar-width: 250px;
    }
}

@media (max-width: 768px) {
    .mobile-menu-toggle {
        display: block;
    }

    .sidebar {
        transform: translateX(-100%);
    }

    .sidebar.active {
        transform: translateX(0);
    }

    .main-content {
        margin-left: 0;
    }

    .content-wrapper {
        padding: calc(var(--spacing-xl) + 60px) var(--spacing-md) var(--spacing-md);
    }

    .page-title {
        font-size: var(--font-size-2xl);
    }

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

    .about-content {
        flex-direction: column;
    }

    .tab-navigation {
        overflow-x: auto;
        scrollbar-width: thin;
    }

    .card-grid {
        grid-template-columns: 1fr;
    }

    .footer-content {
        grid-template-columns: 1fr;
        text-align: center;
    }

    .social-links {
        justify-content: center;
    }
}

@media (max-width: 480px) {
    .content-wrapper {
        padding: calc(var(--spacing-lg) + 60px) var(--spacing-sm) var(--spacing-sm);
    }

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

    .section {
        padding: var(--spacing-md);
    }
}

/* ================================
   UTILITIES
   ================================ */

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

.mt-1 { margin-top: var(--spacing-sm); }
.mt-2 { margin-top: var(--spacing-md); }
.mt-3 { margin-top: var(--spacing-lg); }

.mb-1 { margin-bottom: var(--spacing-sm); }
.mb-2 { margin-bottom: var(--spacing-md); }
.mb-3 { margin-bottom: var(--spacing-lg); }