/* ========================================
   Vietnam Airlines Clone - Core Design System
   Premium & Modern Redesign
   ======================================== */

/* Import Google Fonts */
@import url('https://fonts.googleapis.com/css2?family=Open+Sans:wght@300;400;500;600;700;800&display=swap');

/* CSS Variables - Design Tokens */
:root {
    /* Primary Colors - VNA Official */
    --color-primary: #005f6e;
    --color-primary-dark: #004850;
    --color-primary-light: #00676e;
    --color-primary-gradient: linear-gradient(180deg, #004850 0%, #00676e 100%);

    /* Accent Colors - VNA Gold */
    --color-accent: #d4a017;
    --color-accent-light: #e6b833;
    --color-accent-dark: #b8860b;

    /* Alert Colors */
    --color-alert: #e53935;
    --color-success: #43a047;

    /* Neutral Colors */
    --color-white: #ffffff;
    --color-light: #f5f7fa;
    --color-gray-50: #fafbfc;
    --color-gray-100: #f1f3f5;
    --color-gray-200: #e9ecef;
    --color-gray-300: #dee2e6;
    --color-gray-400: #ced4da;
    --color-gray-500: #adb5bd;
    --color-gray-600: #868e96;
    --color-gray-700: #495057;
    --color-gray-800: #343a40;
    --color-dark: #212529;

    /* Typography */
    --font-family: 'Open Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-size-xs: 0.75rem;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 2rem;
    --font-size-4xl: 2.5rem;
    --font-size-5xl: 3.5rem;

    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    --spacing-3xl: 4rem;
    --spacing-4xl: 6rem;

    /* Borders */
    --border-radius-sm: 6px;
    --border-radius-md: 10px;
    --border-radius-lg: 16px;
    --border-radius-xl: 24px;
    --border-radius-2xl: 32px;
    --border-radius-full: 50%;

    /* Shadows - Premium soft shadows */
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.04);
    --shadow-md: 0 4px 20px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 8px 40px rgba(0, 0, 0, 0.12);
    --shadow-xl: 0 16px 60px rgba(0, 0, 0, 0.16);
    --shadow-2xl: 0 24px 80px rgba(0, 0, 0, 0.2);

    /* Transitions */
    --transition-fast: 200ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-normal: 300ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 500ms cubic-bezier(0.4, 0, 0.2, 1);

    /* Layout */
    --sidebar-width: 260px;
    /* Always expanded like VNA original */
    --sidebar-width-expanded: 260px;
    --header-height: 64px;
    --max-width: 1400px;
}

/* Reset & Base Styles */
*,
*::before,
*::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

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

body {
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    line-height: 1.6;
    color: var(--color-dark);
    background-color: var(--color-light);
    overflow-x: hidden;
}

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

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

button {
    font-family: inherit;
    cursor: pointer;
    border: none;
    background: none;
}

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

ul,
ol {
    list-style: none;
}

input,
select,
textarea {
    font-family: inherit;
    font-size: inherit;
    border: none;
    outline: none;
}

/* Utility Classes */
.container {
    width: 100%;
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 var(--spacing-xl);
}

/* Main Layout */
.main-wrapper {
    display: flex;
    min-height: 100vh;
}

.main-content {
    flex: 1;
    margin-left: var(--sidebar-width);
    transition: margin-left var(--transition-normal);
}

/* Premium Button Styles */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-md) var(--spacing-xl);
    font-weight: 600;
    font-size: var(--font-size-sm);
    border-radius: var(--border-radius-lg);
    transition: all var(--transition-fast);
    cursor: pointer;
    border: none;
    position: relative;
    overflow: hidden;
}

.btn-primary {
    background: var(--color-primary);
    color: var(--color-white);
    box-shadow: 0 4px 14px rgba(0, 95, 110, 0.35);
}

.btn-primary:hover {
    background: var(--color-primary-dark);
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(0, 95, 110, 0.45);
}

.btn-accent {
    background: linear-gradient(135deg, var(--color-accent) 0%, var(--color-accent-dark) 100%);
    color: var(--color-white);
    box-shadow: 0 4px 14px rgba(212, 160, 23, 0.35);
}

.btn-accent:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(212, 160, 23, 0.45);
}

/* Glassmorphism Effect */
.glass {
    background: rgba(255, 255, 255, 0.92);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: 1px solid rgba(255, 255, 255, 0.6);
}

/* Premium Card */
.card {
    background: var(--color-white);
    border-radius: var(--border-radius-xl);
    box-shadow: var(--shadow-lg);
    overflow: hidden;
    transition: all var(--transition-normal);
}

.card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-xl);
}

/* Animations */
@keyframes fadeIn {
    from {
        opacity: 0;
    }

    to {
        opacity: 1;
    }
}

@keyframes slideUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes float {

    0%,
    100% {
        transform: translateY(0);
    }

    50% {
        transform: translateY(-10px);
    }
}

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

.animate-slide-up {
    animation: slideUp 0.6s ease forwards;
}

/* Custom Scrollbar */
::-webkit-scrollbar {
    width: 6px;
    height: 6px;
}

::-webkit-scrollbar-track {
    background: transparent;
}

::-webkit-scrollbar-thumb {
    background: var(--color-gray-300);
    border-radius: 10px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--color-gray-400);
}

/* Selection */
::selection {
    background: var(--color-primary);
    color: var(--color-white);
}