/* ===== GLOBAL STYLES ===== */
:root {
    --primary-color: #007bff;
    --secondary-color: #6c757d;
    --success-color: #28a745;
    --info-color: #17a2b8;
    --warning-color: #ffc107;
    --danger-color: #dc3545;
    --light-color: #f8f9fa;
    --dark-color: #343a40;
    --white: #ffffff;
    --gray-100: #f8f9fa;
    --gray-200: #e9ecef;
    --gray-300: #dee2e6;
    --gray-400: #ced4da;
    --gray-500: #adb5bd;
    --gray-600: #6c757d;
    --gray-700: #495057;
    --gray-800: #343a40;
    --gray-900: #212529;

    --font-family-sans: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    --font-family-mono: SFMono-Regular, Menlo, Monaco, Consolas, monospace;

    --border-radius: 0.375rem;
    --border-radius-lg: 0.5rem;
    --border-radius-xl: 1rem;

    --box-shadow: 0 0.125rem 0.25rem rgba(0, 0, 0, 0.075);
    --box-shadow-sm: 0 0.125rem 0.25rem rgba(0, 0, 0, 0.075);
    --box-shadow-lg: 0 1rem 3rem rgba(0, 0, 0, 0.175);

    --transition: all 0.3s ease-in-out;
}

* {
    box-sizing: border-box;
}

body {
    font-family: var(--font-family-sans), ui-sans-serif;
    line-height: 1.6;
    color: var(--gray-800);
    background-color: var(--white);
}

/* ===== NAVIGATION STYLES ===== */
.navbar {
    padding: 0.75rem 0;
    transition: var(--transition);
}

.navbar-brand {
    font-weight: 700;
    font-size: 1.5rem;
    transition: var(--transition);
}

.navbar-brand:hover {
    transform: scale(1.05);
}

.navbar-nav .nav-link {
    font-weight: 500;
    position: relative;
    transition: var(--transition);
    margin: 0 0.25rem;
    padding: 0.5rem 1rem !important;
    border-radius: var(--border-radius);
}

.navbar-nav .nav-link:hover {
    background-color: var(--gray-100);
    color: var(--primary-color) !important;
    transform: translateY(-2px);
}

.navbar-nav .nav-link::after {
    content: '';
    position: absolute;
    width: 0;
    height: 2px;
    bottom: 0;
    left: 50%;
    background-color: var(--primary-color);
    transition: var(--transition);
    transform: translateX(-50%);
}

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

/* ===== HEADER STYLES ===== */
.display-4 {
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 2rem;
    position: relative;
}

.display-4::after {
    content: '';
    position: absolute;
    bottom: -0.5rem;
    left: 50%;
    transform: translateX(-50%);
    width: 80px;
    height: 3px;
    background: linear-gradient(90deg, var(--primary-color), var(--info-color));
    border-radius: var(--border-radius);
}

/* ===== CARD STYLES ===== */
.card {
    border: none;
    border-radius: var(--border-radius-lg);
    box-shadow: var(--box-shadow);
    transition: var(--transition);
    overflow: hidden;
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: var(--box-shadow-lg);
}

.card-header {
    background: linear-gradient(135deg, var(--primary-color), var(--info-color));
    color: var(--white);
    font-weight: 600;
    border-bottom: none;
}

/* ===== BUTTON STYLES ===== */
.btn {
    border-radius: var(--border-radius);
    font-weight: 500;
    padding: 0.75rem 1.5rem;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
    transition: var(--transition);
}

.btn:hover::before {
    left: 100%;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary-color), #0056b3);
    border: none;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0, 123, 255, 0.3);
}

.btn-secondary {
    background: linear-gradient(135deg, var(--secondary-color), #5a6268);
    border: none;
}

.btn-success {
    background: linear-gradient(135deg, var(--success-color), #1e7e34);
    border: none;
}

/* ===== IMAGE STYLES ===== */
.img-responsive {
    max-width: 100%;
    height: auto;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    transition: var(--transition);
}

.img-responsive:hover {
    transform: scale(1.02);
    box-shadow: var(--box-shadow-lg);
}

/* ===== VIDEO STYLES ===== */
video {
    max-width: 100%;
    height: auto;
    border-radius: var(--border-radius-lg);
    box-shadow: var(--box-shadow-lg);
    transition: var(--transition);
}

video:hover {
    transform: scale(1.02);
    box-shadow: 0 1rem 3rem rgba(0, 0, 0, 0.25);
}

/* ===== CONTENT STYLES ===== */
.content-section {
    padding: 3rem 0;
}

.content-section:nth-child(even) {
    background-color: var(--gray-100);
}

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

.text-muted {
    color: var(--gray-600) !important;
}

/* ===== HR STYLES ===== */
.hr, hr {
    margin: 2rem 0;
    border: none;
    height: 2px;
    background: linear-gradient(90deg, transparent, var(--primary-color), transparent);
}

/* ===== FOOTER STYLES ===== */
.footer {
    background: linear-gradient(135deg, var(--gray-800), var(--gray-900));
    color: var(--gray-300);
    padding: 2rem 0 1rem;
    margin-top: 3rem;
}

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

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

/* ===== ANIMATION UTILITIES ===== */
@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);
    }
}

@keyframes pulse {
    0%, 100% {
        opacity: 1;
    }
    50% {
        opacity: 0.7;
    }
}

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

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

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

.pulse {
    animation: pulse 2s infinite;
}

/* ===== RESPONSIVE DESIGN ===== */
@media (max-width: 768px) {
    .navbar-brand img {
        width: 150px !important;
        height: 60px !important;
    }

    .display-4 {
        font-size: 2rem;
    }

    .btn {
        padding: 0.5rem 1rem;
        font-size: 0.875rem;
    }

    .content-section {
        padding: 2rem 0;
    }

    video {
        width: 100% !important;
        height: auto !important;
    }
}

@media (max-width: 576px) {
    .navbar-brand img {
        width: 120px !important;
        height: 50px !important;
    }

    .display-4 {
        font-size: 1.75rem;
    }

    .container {
        padding: 0 1rem;
    }
}

/* ===== 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;
    }
}

/* ===== DARK MODE SUPPORT ===== */
@media (prefers-color-scheme: dark) {
    :root {
        --primary-color: #4dabf7;
        --secondary-color: #868e96;
        --background-color: #121212;
        --surface-color: #1e1e1e;
        --text-color: #ffffff;
        --text-secondary: #adb5bd;
    }

    body {
        background-color: var(--background-color);
        color: var(--text-color);
    }

    .card {
        background-color: var(--surface-color);
        color: var(--text-color);
    }

    .navbar {
        background-color: var(--surface-color) !important;
    }

    .navbar-nav .nav-link {
        color: var(--text-color) !important;
    }

    .navbar-nav .nav-link:hover {
        background-color: rgba(255, 255, 255, 0.1);
    }
}

/* ===== UTILITY CLASSES ===== */
.text-gradient {
    background: linear-gradient(135deg, var(--primary-color), var(--info-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.shadow-sm {
    box-shadow: var(--box-shadow-sm) !important;
}

.shadow {
    box-shadow: var(--box-shadow) !important;
}

.shadow-lg {
    box-shadow: var(--box-shadow-lg) !important;
}

.rounded {
    border-radius: var(--border-radius) !important;
}

.rounded-lg {
    border-radius: var(--border-radius-lg) !important;
}

.rounded-xl {
    border-radius: var(--border-radius-xl) !important;
}

/* ===== LOADING STATES ===== */
.loading {
    position: relative;
    overflow: hidden;
}

.loading::after {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.4), transparent);
    animation: loading 1.5s infinite;
}

@keyframes loading {
    0% {
        left: -100%;
    }
    100% {
        left: 100%;
    }
}

/* ===== HOVER EFFECTS ===== */
.hover-lift {
    transition: var(--transition);
}

.hover-lift:hover {
    transform: translateY(-5px);
    box-shadow: var(--box-shadow-lg);
}

.hover-scale {
    transition: var(--transition);
}

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

/* ===== FOCUS STATES ===== */
.btn:focus,
.form-control:focus,
.form-select:focus {
    box-shadow: 0 0 0 0.2rem rgba(0, 123, 255, 0.25);
    border-color: var(--primary-color);
    outline: none;
}