/**
 * Core CSS - Style cơ bản của trang web
 * File này chỉ chứa CSS cơ bản nhất, không chứa các thành phần cụ thể
 */

/* ===== CSS VARIABLES ===== */
:root {
    /* Colors */
    --primary: #4361ee;
    --primary-dark: #3a56d4;
    --secondary: #3f37c9;
    --success: #4cc9f0;
    --danger: #ef476f;
    --warning: #ffd166;
    --light: #f8f9fa;
    --dark: #212529;
    --gray: #6c757d;
    --gray-light: #e9ecef;
    
    /* Sizes & Spacing */
    --border-radius: 8px;
    --transition-speed: 0.3s;
    --shadow: 0 2px 12px rgba(0, 0, 0, 0.08);
    --section-padding: 80px 0;
    
    /* Component-specific */
    --sidebar-width: 260px;
    --sidebar-collapsed-width: 70px;
    --header-height: 60px;
}

/* ===== RESET & BASE STYLES ===== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
    background-color: #f5f7fb;
    color: var(--dark);
    line-height: 1.5;
}

a {
    text-decoration: none;
    color: inherit;
}

ul {
    list-style-type: none;
}

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

button, input, select, textarea {
    font-family: inherit;
}

/* Remove focus outline for mouse users but keep for keyboard users */
*:focus-visible {
    outline: 2px solid var(--primary);
    outline-offset: 2px;
}

/* ===== CONTAINER ===== */
.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 15px;
}

/* ===== STARS RATING ===== */
.stars {
    color: var(--warning);
    display: inline-flex;
}

/* ===== HELPERS ===== */
/* Hide elements visually but keep them accessible for screen readers */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border-width: 0;
}

/* Force a line break */
.break {
    flex-basis: 100%;
    width: 0;
}

/* Clearfix for floating elements */
.clearfix::after {
    content: "";
    display: table;
    clear: both;
}

/* ===== DROPDOWN MENU ===== */
.dropdown {
    position: relative;
    display: inline-block;
}

.dropdown-content {
    position: absolute;
    top: 100%;
    right: 0;
    background-color: white;
    min-width: 160px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    border-radius: var(--border-radius);
    padding: 5px 0;
    z-index: 1000;
    display: none;
    opacity: 0;
    transform: translateY(10px);
    transition: all 0.3s;
}

.dropdown-content.show {
    display: block;
    opacity: 1;
    transform: translateY(0);
}

.dropdown-item {
    display: flex;
    align-items: center;
    padding: 8px 15px;
    color: var(--dark);
    cursor: pointer;
    transition: background-color 0.2s;
}

.dropdown-item:hover {
    background-color: var(--gray-light);
}

.dropdown-item i {
    margin-right: 10px;
    font-size: 14px;
    color: var(--gray);
}

.dropdown-divider {
    height: 1px;
    background-color: var(--gray-light);
    margin: 5px 0;
}

/* ===== RESPONSIVE IMAGES ===== */
.img-fluid {
    max-width: 100%;
    height: auto;
}

.img-thumbnail {
    padding: 0.25rem;
    background-color: #fff;
    border: 1px solid var(--gray-light);
    border-radius: var(--border-radius);
    max-width: 100%;
    height: auto;
}

/* ===== TABLE BASE STYLES ===== */
table {
    border-collapse: collapse;
    width: 100%;
}

th, td {
    text-align: left;
    padding: 8px;
}

/* ===== MEDIA QUERY BREAKPOINTS ===== */
/* These are just empty selectors to document the standard breakpoints */
/* Small devices (landscape phones, 576px and up) */
@media (min-width: 576px) {
    /* styles for small devices */
}

/* Medium devices (tablets, 768px and up) */
@media (min-width: 768px) {
    /* styles for medium devices */
}

/* Large devices (desktops, 992px and up) */
@media (min-width: 992px) {
    /* styles for large devices */
}

/* Extra large devices (large desktops, 1200px and up) */
@media (min-width: 1200px) {
    /* styles for extra large devices */
}