/*
========================================
DAY 2: CSS TRAINING STYLES
========================================
Shared stylesheet for all Day 2 lesson pages.
Includes the 12-column responsive grid system,
shared layout/component styles, and per-lesson demo styles.
*/

/* ========================================
   1. BASE RESET
   ======================================== */

* {
  box-sizing: border-box;
}

/* ========================================
   2. 12-COLUMN GRID SYSTEM (MOBILE-FIRST)
   ======================================== */

/* --- Base Row --- */
.row {
  display: flex;
  flex-wrap: wrap;
  margin-left: auto;
  margin-right: auto;
  width: 100%;
}

/* --- Base Columns (Mobile Default) --- */
.col-1 {
  flex: 0 0 calc((1 / 12) * 100%);
  max-width: calc((1 / 12) * 100%);
}

.col-2 {
  flex: 0 0 calc((2 / 12) * 100%);
  max-width: calc((2 / 12) * 100%);
}

.col-3 {
  flex: 0 0 calc((3 / 12) * 100%);
  max-width: calc((3 / 12) * 100%);
}

.col-4 {
  flex: 0 0 calc((4 / 12) * 100%);
  max-width: calc((4 / 12) * 100%);
}

.col-5 {
  flex: 0 0 calc((5 / 12) * 100%);
  max-width: calc((5 / 12) * 100%);
}

.col-6 {
  flex: 0 0 calc((6 / 12) * 100%);
  max-width: calc((6 / 12) * 100%);
}

.col-7 {
  flex: 0 0 calc((7 / 12) * 100%);
  max-width: calc((7 / 12) * 100%);
}

.col-8 {
  flex: 0 0 calc((8 / 12) * 100%);
  max-width: calc((8 / 12) * 100%);
}

.col-9 {
  flex: 0 0 calc((9 / 12) * 100%);
  max-width: calc((9 / 12) * 100%);
}

.col-10 {
  flex: 0 0 calc((10 / 12) * 100%);
  max-width: calc((10 / 12) * 100%);
}

.col-11 {
  flex: 0 0 calc((11 / 12) * 100%);
  max-width: calc((11 / 12) * 100%);
}

.col-12 {
  flex: 0 0 100%;
  max-width: 100%;
}

/* --- Small Devices (>576px) --- */
@media only screen and (min-width: 576px) {
  .row {
    max-width: 540px;
  }

  .col-1-sm {
    flex: 0 0 calc((1 / 12) * 100%);
    max-width: calc((1 / 12) * 100%);
  }

  .col-2-sm {
    flex: 0 0 calc((2 / 12) * 100%);
    max-width: calc((2 / 12) * 100%);
  }

  .col-3-sm {
    flex: 0 0 calc((3 / 12) * 100%);
    max-width: calc((3 / 12) * 100%);
  }

  .col-4-sm {
    flex: 0 0 calc((4 / 12) * 100%);
    max-width: calc((4 / 12) * 100%);
  }

  .col-5-sm {
    flex: 0 0 calc((5 / 12) * 100%);
    max-width: calc((5 / 12) * 100%);
  }

  .col-6-sm {
    flex: 0 0 calc((6 / 12) * 100%);
    max-width: calc((6 / 12) * 100%);
  }

  .col-7-sm {
    flex: 0 0 calc((7 / 12) * 100%);
    max-width: calc((7 / 12) * 100%);
  }

  .col-8-sm {
    flex: 0 0 calc((8 / 12) * 100%);
    max-width: calc((8 / 12) * 100%);
  }

  .col-9-sm {
    flex: 0 0 calc((9 / 12) * 100%);
    max-width: calc((9 / 12) * 100%);
  }

  .col-10-sm {
    flex: 0 0 calc((10 / 12) * 100%);
    max-width: calc((10 / 12) * 100%);
  }

  .col-11-sm {
    flex: 0 0 calc((11 / 12) * 100%);
    max-width: calc((11 / 12) * 100%);
  }

  .col-12-sm {
    flex: 0 0 100%;
    max-width: 100%;
  }
}

/* --- Medium Devices (>=768px) --- */
@media only screen and (min-width: 768px) {
  .row {
    max-width: 720px;
  }

  .col-1-md {
    flex: 0 0 calc((1 / 12) * 100%);
    max-width: calc((1 / 12) * 100%);
  }

  .col-2-md {
    flex: 0 0 calc((2 / 12) * 100%);
    max-width: calc((2 / 12) * 100%);
  }

  .col-3-md {
    flex: 0 0 calc((3 / 12) * 100%);
    max-width: calc((3 / 12) * 100%);
  }

  .col-4-md {
    flex: 0 0 calc((4 / 12) * 100%);
    max-width: calc((4 / 12) * 100%);
  }

  .col-5-md {
    flex: 0 0 calc((5 / 12) * 100%);
    max-width: calc((5 / 12) * 100%);
  }

  .col-6-md {
    flex: 0 0 calc((6 / 12) * 100%);
    max-width: calc((6 / 12) * 100%);
  }

  .col-7-md {
    flex: 0 0 calc((7 / 12) * 100%);
    max-width: calc((7 / 12) * 100%);
  }

  .col-8-md {
    flex: 0 0 calc((8 / 12) * 100%);
    max-width: calc((8 / 12) * 100%);
  }

  .col-9-md {
    flex: 0 0 calc((9 / 12) * 100%);
    max-width: calc((9 / 12) * 100%);
  }

  .col-10-md {
    flex: 0 0 calc((10 / 12) * 100%);
    max-width: calc((10 / 12) * 100%);
  }

  .col-11-md {
    flex: 0 0 calc((11 / 12) * 100%);
    max-width: calc((11 / 12) * 100%);
  }

  .col-12-md {
    flex: 0 0 100%;
    max-width: 100%;
  }
}

/* --- Large Devices (>=992px) --- */
@media only screen and (min-width: 992px) {
  .row {
    max-width: 960px;
  }

  .col-1-lg {
    flex: 0 0 calc((1 / 12) * 100%);
    max-width: calc((1 / 12) * 100%);
  }

  .col-2-lg {
    flex: 0 0 calc((2 / 12) * 100%);
    max-width: calc((2 / 12) * 100%);
  }

  .col-3-lg {
    flex: 0 0 calc((3 / 12) * 100%);
    max-width: calc((3 / 12) * 100%);
  }

  .col-4-lg {
    flex: 0 0 calc((4 / 12) * 100%);
    max-width: calc((4 / 12) * 100%);
  }

  .col-5-lg {
    flex: 0 0 calc((5 / 12) * 100%);
    max-width: calc((5 / 12) * 100%);
  }

  .col-6-lg {
    flex: 0 0 calc((6 / 12) * 100%);
    max-width: calc((6 / 12) * 100%);
  }

  .col-7-lg {
    flex: 0 0 calc((7 / 12) * 100%);
    max-width: calc((7 / 12) * 100%);
  }

  .col-8-lg {
    flex: 0 0 calc((8 / 12) * 100%);
    max-width: calc((8 / 12) * 100%);
  }

  .col-9-lg {
    flex: 0 0 calc((9 / 12) * 100%);
    max-width: calc((9 / 12) * 100%);
  }

  .col-10-lg {
    flex: 0 0 calc((10 / 12) * 100%);
    max-width: calc((10 / 12) * 100%);
  }

  .col-11-lg {
    flex: 0 0 calc((11 / 12) * 100%);
    max-width: calc((11 / 12) * 100%);
  }

  .col-12-lg {
    flex: 0 0 100%;
    max-width: 100%;
  }
}

/* --- Extra Large Devices (>=1200px) --- */
@media only screen and (min-width: 1200px) {
  .row {
    max-width: 1140px;
  }

  .col-1-xl {
    flex: 0 0 calc((1 / 12) * 100%);
    max-width: calc((1 / 12) * 100%);
  }

  .col-2-xl {
    flex: 0 0 calc((2 / 12) * 100%);
    max-width: calc((2 / 12) * 100%);
  }

  .col-3-xl {
    flex: 0 0 calc((3 / 12) * 100%);
    max-width: calc((3 / 12) * 100%);
  }

  .col-4-xl {
    flex: 0 0 calc((4 / 12) * 100%);
    max-width: calc((4 / 12) * 100%);
  }

  .col-5-xl {
    flex: 0 0 calc((5 / 12) * 100%);
    max-width: calc((5 / 12) * 100%);
  }

  .col-6-xl {
    flex: 0 0 calc((6 / 12) * 100%);
    max-width: calc((6 / 12) * 100%);
  }

  .col-7-xl {
    flex: 0 0 calc((7 / 12) * 100%);
    max-width: calc((7 / 12) * 100%);
  }

  .col-8-xl {
    flex: 0 0 calc((8 / 12) * 100%);
    max-width: calc((8 / 12) * 100%);
  }

  .col-9-xl {
    flex: 0 0 calc((9 / 12) * 100%);
    max-width: calc((9 / 12) * 100%);
  }

  .col-10-xl {
    flex: 0 0 calc((10 / 12) * 100%);
    max-width: calc((10 / 12) * 100%);
  }

  .col-11-xl {
    flex: 0 0 calc((11 / 12) * 100%);
    max-width: calc((11 / 12) * 100%);
  }

  .col-12-xl {
    flex: 0 0 100%;
    max-width: 100%;
  }
}

/* --- XXL Devices (>=1400px) --- */
@media only screen and (min-width: 1400px) {
  .row {
    max-width: 1320px;
  }

  .col-1-2xl {
    flex: 0 0 calc((1 / 12) * 100%);
    max-width: calc((1 / 12) * 100%);
  }

  .col-2-2xl {
    flex: 0 0 calc((2 / 12) * 100%);
    max-width: calc((2 / 12) * 100%);
  }

  .col-3-2xl {
    flex: 0 0 calc((3 / 12) * 100%);
    max-width: calc((3 / 12) * 100%);
  }

  .col-4-2xl {
    flex: 0 0 calc((4 / 12) * 100%);
    max-width: calc((4 / 12) * 100%);
  }

  .col-5-2xl {
    flex: 0 0 calc((5 / 12) * 100%);
    max-width: calc((5 / 12) * 100%);
  }

  .col-6-2xl {
    flex: 0 0 calc((6 / 12) * 100%);
    max-width: calc((6 / 12) * 100%);
  }

  .col-7-2xl {
    flex: 0 0 calc((7 / 12) * 100%);
    max-width: calc((7 / 12) * 100%);
  }

  .col-8-2xl {
    flex: 0 0 calc((8 / 12) * 100%);
    max-width: calc((8 / 12) * 100%);
  }

  .col-9-2xl {
    flex: 0 0 calc((9 / 12) * 100%);
    max-width: calc((9 / 12) * 100%);
  }

  .col-10-2xl {
    flex: 0 0 calc((10 / 12) * 100%);
    max-width: calc((10 / 12) * 100%);
  }

  .col-11-2xl {
    flex: 0 0 calc((11 / 12) * 100%);
    max-width: calc((11 / 12) * 100%);
  }

  .col-12-2xl {
    flex: 0 0 100%;
    max-width: 100%;
  }
}

/* ========================================
   3. CONTAINER & BODY
   ======================================== */

body {
  font-family: Arial, sans-serif;
  line-height: 1.6;
  background-color: #f9f9f9;
  color: #333;
}

/* Responsive wrapper that provides padding for the fixed header */
.container {
  width: 100%;
  padding: 80px 20px 20px;
}

/* ========================================
   4. STICKY HEADER & DROPDOWN
   ======================================== */

.sticky-header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 60px;
  background-color: white;
  color: #032340;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 max(20px, calc(50vw - 660px));
  box-shadow: 0 2px 5px rgba(0, 0, 0, 0.2);
  z-index: 1000;
}

.header-left {
  display: flex;
  align-items: center;
  gap: 20px;
}

.home-link {
  color: #34495e;
  text-decoration: none;
  font-weight: bold;
  font-size: 1.1rem;
  display: flex;
  align-items: center;
  gap: 5px;
}

.home-link:hover {
  color: hsl(210, 27%, 50%);
}

.page-title {
  font-size: 1rem;
  color: #34495e;
  opacity: 0.8;
  display: none;
  /* Hidden on small screens */
}

/* --- Dropdown --- */
.dropdown {
  position: relative;
  display: inline-block;
}

.dropbtn {
  background-color: #34495e;
  color: white;
  padding: 8px 16px;
  font-size: 14px;
  border: none;
  border-radius: 4px;
  cursor: pointer;
}

.dropdown:hover .dropbtn {
  background-color: hsl(210, 27%, 50%);
}

.dropdown-content {
  display: none;
  position: absolute;
  right: 0;
  background-color: #f9f9f9;
  min-width: 260px;
  box-shadow: 0 8px 16px rgba(0, 0, 0, 0.2);
  z-index: 1;
  border-radius: 4px;
  max-height: 400px;
  overflow-y: auto;
}

.dropdown-content a {
  color: black;
  padding: 12px 16px;
  text-decoration: none;
  display: block;
  font-size: 0.9rem;
  border-bottom: 1px solid #eee;
  text-align: left;
}

.dropdown-content a:hover {
  background-color: #f1f1f1;
}

.dropdown:hover .dropdown-content {
  display: block;
}

/* Show page title on wider screens */
@media (min-width: 600px) {
  .page-title {
    display: block;
  }
}

/* ========================================
   5. SHARED LESSON COMPONENTS
   ======================================== */

/* --- Main Title --- */
h1.main-title {
  color: hsl(210, 27%, 50%);
  text-align: center;
  font-size: 2.5rem;
  margin-bottom: 10px;
  border-bottom: 2px solid hsl(210, 27%, 50%);
  padding-bottom: 0.5rem;
}

/* --- Section Title --- */
.section-title {
  color: #333;
  border-bottom: 2px solid #ddd;
  padding-bottom: 10px;
  margin-top: 40px;
}

/* --- Example Output --- */
.example-output {
  background-color: white;
  border: 2px dashed #aaa;
  padding: 20px;
  border-radius: 5px;
  margin-top: 10px;
}

/* --- Info & Warning Boxes --- */
.info-box {
  background-color: #e3f2fd;
  border-left: 5px solid #2196f3;
  padding: 15px;
  margin: 15px 0;
  border-radius: 0 5px 5px 0;
}

.info-box-orange {
  background-color: #fff3e0;
  border-left: 5px solid #ff9800;
  padding: 15px;
  margin: 15px 0;
  border-radius: 0 5px 5px 0;
}

.warning-box {
  background-color: #ffebee;
  border-left: 5px solid #f44336;
  padding: 15px;
  margin: 15px 0;
  border-radius: 0 5px 5px 0;
}

.resize-hint {
  background-color: #fff3e0;
  border-left: 5px solid #ff9800;
  padding: 15px;
  margin-bottom: 20px;
  color: #e65100;
}

/* --- Comparison & Specificity Tables --- */
.comparison-table,
.specificity-table {
  width: 100%;
  border-collapse: collapse;
  margin: 15px 0;
}

.comparison-table th,
.comparison-table td,
.specificity-table th,
.specificity-table td {
  border: 1px solid #ddd;
  padding: 12px;
  text-align: left;
}

.comparison-table th,
.specificity-table th {
  background-color: #f5f5f5;
  font-weight: bold;
}

.comparison-table tr:nth-child(even),
.specificity-table tr:nth-child(even) {
  background-color: #fafafa;
}

.pros {
  color: #4caf50;
}

.cons {
  color: #f44336;
}

.specificity-value {
  font-family: "Courier New", monospace;
  font-weight: bold;
  color: #e06c75;
}

/* --- Navigation Links --- */
.nav-links {
  margin-top: 50px;
  text-align: center;
  padding: 20px;
  background-color: #fff;
  border-top: 1px solid #ddd;
}

.nav-links a {
  text-decoration: none;
  color: #34495e;
  font-weight: bold;
  margin: 0 10px;
}

.nav-links a:hover {
  text-decoration: underline;
}

/* ========================================
   6. INDEX PAGE STYLES
   ======================================== */

.page-index {
  font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
  background-color: #f0f2f5;
}

.page-index h1 {
  color: hsl(210, 27%, 50%);
  border-bottom: 2px solid hsl(210, 27%, 50%);
  padding-bottom: 0.5rem;
}

/* Lesson card list */
.lesson-list {
  list-style-type: none;
  padding: 0;
  margin: 1rem 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 1rem;
}

@media (min-width: 576px) {
  .lesson-list {
    grid-template-columns: 1fr 1fr;
  }
}

.lesson-card {
  background: white;
  padding: 1rem;
  border-radius: 8px;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
  transition:
    transform 0.2s,
    box-shadow 0.2s;
  display: flex;
  align-items: center;
  margin-bottom: 1rem;
}

.lesson-card:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
}

.lesson-card a {
  text-decoration: none;
  color: #34495e;
  font-weight: 500;
  flex-grow: 1;
}

.file-name {
  font-size: 0.85rem;
  color: #7f8c8d;
  font-family: monospace;
}

.back-link {
  display: inline-block;
  margin-top: 2rem;
  color: #666;
  font-size: 0.9rem;
}

/* ========================================
   7. LESSON 00: CSS INTRO
   ======================================== */

.benefit-list {
  list-style-type: none;
  padding: 0;
}

.benefit-list li {
  padding: 8px 0;
  padding-left: 25px;
  position: relative;
}

.benefit-list li::before {
  content: "\2713";
  color: #4caf50;
  font-weight: bold;
  position: absolute;
  left: 0;
}

/* ========================================
   8. LESSON 01: CSS SYNTAX
   ======================================== */

.styled-text {
  color: blue;
  font-size: 20px;
  font-weight: bold;
}

.multi-property-box {
  width: 200px;
  height: 100px;
  background-color: purple;
  color: white;
  text-align: center;
  line-height: 100px;
  /* Vertically centers text */
  border-radius: 10px;
}

/* ========================================
   9. LESSON 04: CSS SELECTORS
   ======================================== */

/* Element Selector Demo */
p.element-selector-demo {
  color: green;
  font-weight: bold;
}

/* Class Selector Demo */
.highlight {
  background-color: yellow;
  color: red;
  font-weight: bold;
  padding: 5px;
}

/* ID Selector Demo */
#unique-element {
  border: 2px solid orange;
  padding: 10px;
  background-color: #fff3e0;
  color: #d84315;
}

/* Group Selector Demo */
.group-demo-h3,
.group-demo-h4 {
  color: purple;
  text-decoration: underline;
}

/* Descendant Selector Demo */
.descendant-container p {
  color: teal;
  font-style: italic;
}

/* Child Selector Demo */
.child-parent > p {
  border-left: 5px solid blue;
  padding-left: 10px;
  background-color: #e3f2fd;
}

/* Attribute Selector Demo */
.lesson-04 input[type="text"] {
  border: 2px solid red;
  padding: 5px;
}

.lesson-04 input[type="email"] {
  border: 2px solid green;
  padding: 5px;
}

/* Pseudo-class Selector Demo */
.hover-link {
  color: blue;
  text-decoration: none;
  font-size: 1.2rem;
  transition: color 0.3s;
}

.hover-link:hover {
  color: red;
  text-decoration: underline;
}

.list-demo li:first-child {
  color: red;
  font-weight: bold;
}

.list-demo li:last-child {
  color: blue;
  font-weight: bold;
}

/* Pseudo-element Selector Demo */
.pseudo-demo::before {
  content: "\1F449 ";
  /* pointing right */
}

.pseudo-demo::after {
  content: " \1F448";
  /* pointing left */
}

/* ========================================
   10. LESSON 05: BOX MODEL
   ======================================== */

.lesson-05 .box {
  background-color: #e0e0e0;
  border: 1px solid #999;
  display: inline-block;
  margin-bottom: 10px;
}

/* Padding */
.pad-none {
  padding: 0;
}

.pad-20 {
  padding: 20px;
  background-color: #c8e6c9;
}

.pad-mixed {
  padding: 10px 40px;
  background-color: #b9f6ca;
}

/* Margin */
.marg-none {
  margin: 0;
}

.marg-20 {
  margin: 20px;
  background-color: #ffccbc;
}

.marg-auto {
  margin: 0 auto;
  display: block !important;
  width: 50%;
  background-color: #ffe0b2;
}

/* Border */
.bord-solid {
  border: 5px solid red;
}

.bord-dotted {
  border: 5px dotted blue;
}

.bord-mixed {
  border-top: 5px solid red;
  border-bottom: 5px dashed green;
}

/* Border Radius */
.rad-small {
  border-radius: 5px;
  padding: 10px;
  border: 2px solid #333;
}

.rad-large {
  border-radius: 20px;
  padding: 10px;
  border: 2px solid #333;
}

.rad-circle {
  width: 100px;
  height: 100px;
  border-radius: 50%;
  border: 2px solid #333;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
}

/* Box Sizing */
.sizing-demo {
  width: 200px;
  height: 100px;
  padding: 20px;
  border: 10px solid blue;
  background-color: #b3e5fc;
  margin-bottom: 20px;
  font-size: 14px;
}

.content-box {
  box-sizing: content-box;
}

.border-box {
  box-sizing: border-box;
}

/* ========================================
   11. LESSON 04: TYPOGRAPHY
   ======================================== */

p.demo {
  margin: 5px 0;
  padding: 5px;
  background-color: #f0f0f0;
  border-left: 3px solid #ccc;
}

/* Font Family */
.font-serif {
  font-family: Georgia, "Times New Roman", serif;
}

.font-sans {
  font-family: Arial, Helvetica, sans-serif;
}

.font-mono {
  font-family: "Courier New", Courier, monospace;
}

/* Font Size */
.size-small {
  font-size: 12px;
}

.size-medium {
  font-size: 16px;
}

.size-large {
  font-size: 24px;
}

.size-xlarge {
  font-size: 32px;
}

/* Font Weight */
.weight-light {
  font-weight: 300;
}

.weight-normal {
  font-weight: 400;
}

.weight-bold {
  font-weight: 700;
}

.weight-bolder {
  font-weight: 900;
}

/* Font Style */
.style-italic {
  font-style: italic;
}

.style-oblique {
  font-style: oblique;
}

/* Text Decoration */
.dec-underline {
  text-decoration: underline;
}

.dec-line-through {
  text-decoration: line-through;
}

.dec-none {
  text-decoration: none;
  border-bottom: none;
}

/* Text Transform */
.trans-upper {
  text-transform: uppercase;
}

.trans-lower {
  text-transform: lowercase;
}

.trans-cap {
  text-transform: capitalize;
}

/* Text Align */
.align-center {
  text-align: center;
}

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

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

/* Line Height */
.lh-small {
  line-height: 1;
  background-color: #ffebee;
}

.lh-large {
  line-height: 2;
  background-color: #e8f5e9;
}

/* Letter Spacing */
.spacing-wide {
  letter-spacing: 5px;
}

.spacing-neg {
  letter-spacing: -1px;
}

/* ========================================
   12. LESSON 05: COLORS
   ======================================== */

/* Base Color Box */
.color-box {
  padding: 20px;
  margin: 10px 0;
  border-radius: 5px;
  font-weight: bold;
  text-align: center;
  color: white;
  font-size: 1.1rem;
  text-shadow: 0 1px 2px rgba(0, 0, 0, 0.3);
}

/* Named Colors */
.named-red {
  background-color: red;
}

.named-blue {
  background-color: blue;
}

.named-green {
  background-color: green;
}

/* Hexadecimal Colors */
.hex-tomato {
  background-color: #ff5733;
}

.hex-green {
  background-color: #33ff57;
}

.hex-blue {
  background-color: #3357ff;
}

/* RGB Colors */
.rgb-coral {
  background-color: rgb(255, 99, 71);
}

.rgb-sea {
  background-color: rgb(60, 179, 113);
}

.rgb-corn {
  background-color: rgb(100, 149, 237);
}

/* RGBA Colors */
.rgba-container {
  background-image: url("data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAoAAAAKCAYAAACNMs+9AAAAHElEQVQYlWNgYGBg+M9AxYBRB4w6YNSBqBwMABm4AwnWgl1WAAAAAElFTkSuQmCC");
  padding: 20px;
  border-radius: 5px;
}

.rgba-100 {
  background-color: rgba(255, 0, 0, 1);
}

.rgba-60 {
  background-color: rgba(255, 0, 0, 0.6);
}

.rgba-30 {
  background-color: rgba(255, 0, 0, 0.3);
}

/* HSL Colors */
.hsl-red {
  background-color: hsl(0, 100%, 50%);
}

.hsl-green {
  background-color: hsl(120, 100%, 50%);
}

.hsl-blue {
  background-color: hsl(240, 100%, 50%);
}

/* ========================================
   13. LESSON 06: CSS VARIABLES & FUNCTIONS
   ======================================== */

:root {
  --primary-color: #e91e63;
  --secondary-color: #3f51b5;
  --box-padding: 20px;
  --border-radius: 8px;
}

.var-box {
  background-color: var(--primary-color);
  color: white;
  padding: var(--box-padding);
  border-radius: var(--border-radius);
  margin-bottom: 10px;
  font-weight: bold;
  text-align: center;
}

.var-box-2 {
  background-color: var(--secondary-color);
  color: white;
  padding: var(--box-padding);
  border-radius: var(--border-radius);
  text-align: center;
  font-weight: bold;
}

.local-scope {
  --primary-color: #4caf50;
  background-color: var(--primary-color);
  padding: var(--box-padding);
  color: white;
  text-align: center;
  font-weight: bold;
  border-radius: var(--border-radius);
}

/* calc() demos */
.calc-container {
  border: 2px solid #333;
  width: 100%;
  padding: 10px;
  background-color: #ddd;
}

.calc-box {
  background-color: #ff9800;
  color: white;
  padding: 10px;
  text-align: center;
  width: calc(100% - 40px);
  margin: 0 auto;
}

.calc-fluid {
  margin-top: 10px;
  background-color: #9c27b0;
  color: white;
  padding: 10px;
  text-align: center;
  width: calc(100% / 3);
}

/* ========================================
   14. LESSON 07: BACKGROUNDS
   ======================================== */

/* Base demo box for backgrounds */
.demo-box {
  width: 100%;
  height: 150px;
  border: 1px solid #ddd;
  margin-bottom: 10px;
  color: white;
  text-shadow: 1px 1px 2px black;
  font-weight: bold;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
}

/* Background Color */
.bg-red {
  background-color: red;
}

.bg-blue {
  background-color: blue;
}

/* Linear Gradient */
.grad-linear {
  background-image: linear-gradient(to right, red, yellow);
}

.grad-linear-deg {
  background-image: linear-gradient(45deg, blue, purple);
}

/* Radial Gradient */
.grad-radial {
  background-image: radial-gradient(circle, red, yellow, green);
}

/* Background Image & Size */
.bg-img-cover {
  background-image: url("../img/bg-beach.jpg");
  background-size: cover;
  background-position: center;
}

.bg-img-contain {
  background-image: url("../img/bg-beach.jpg");
  background-size: contain;
  background-repeat: no-repeat;
  background-color: #333;
}

.demo-box.obj-fit-demo {
  flex-direction: column;
  height: auto;
  gap: 1rem;
}

.img-container {
  width: 100%;
  height: 150px;
  position: relative;
  background-color: #333;
  display: flex;
  justify-content: center;
  align-items: center;
}

.obj-fit-cover {
  object-fit: cover;
  width: 100%;
  height: 100%;
  position: absolute;
}

.obj-fit-contain {
  object-fit: contain;
  width: 100%;
  height: 100%;
  position: absolute;
}

.obj-fit-text {
  z-index: 100;
}

/* Background Position */
.bg-pos-center {
  background-image: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><circle cx="50" cy="50" r="40" fill="gold"/></svg>');
  background-repeat: no-repeat;
  background-size: 50px 50px;
  background-position: center;
  background-color: #eee;
  color: black;
  text-shadow: none;
}

.bg-pos-br {
  background-image: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><circle cx="50" cy="50" r="40" fill="purple"/></svg>');
  background-repeat: no-repeat;
  background-size: 50px 50px;
  background-position: bottom right;
  background-color: #eee;
  color: black;
  text-shadow: none;
}

/* Background Repeat */
.bg-repeat {
  background-image: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 20 20"><rect width="10" height="10" fill="blue"/></svg>');
  background-repeat: repeat;
  background-color: #e3f2fd;
  color: black;
  text-shadow: none;
}

.bg-norepeat {
  background-image: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 20 20"><rect width="10" height="10" fill="red"/></svg>');
  background-repeat: no-repeat;
  background-size: 50px 50px;
  background-position: center;
  background-color: #ffebee;
  color: black;
  text-shadow: none;
}

/* Background Attachment */
.attachment-container {
  height: 200px;
  border: 2px solid #333;
  overflow-y: scroll;
}

.bg-scroll {
  height: 400px;
  background-image: linear-gradient(to bottom, #4facfe, #00f2fe);
  background-attachment: scroll;
  padding: 20px;
}

.bg-fixed {
  height: 400px;
  background-image: linear-gradient(to bottom, #d4fc79, #96e6a1);
  padding: 20px;
}

/* ========================================
   15. LESSON 08: UNITS & SHADOWS
   ======================================== */

.unit-container {
  font-size: 16px;
  border: 1px solid #ccc;
  padding: 10px;
  margin-bottom: 20px;
}

.px-box {
  font-size: 20px;
  background-color: #e0e0e0;
  padding: 10px;
  margin: 5px;
}

.em-box {
  font-size: 1.5em;
  background-color: #d1c4e9;
  padding: 10px;
  margin: 5px;
}

.em-child {
  font-size: 1.5em;
  background-color: #b39ddb;
}

.rem-box {
  font-size: 1.5rem;
  background-color: #c8e6c9;
  padding: 10px;
  margin: 5px;
}

/* Shadows */
.shadow-demo {
  display: flex;
  gap: 20px;
  flex-wrap: wrap;
  padding: 20px;
}

.box-shadow {
  background-color: #fff;
  padding: 20px;
  border: 1px solid #ddd;
  box-shadow: 5px 5px 10px rgba(0, 0, 0, 0.3);
  font-weight: bold;
}

.soft-shadow {
  background-color: #fff;
  padding: 20px;
  box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
  border-radius: 10px;
}

.text-shadow-demo {
  font-size: 2rem;
  font-weight: bold;
  color: #ff5722;
  text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.4);
}

/* --- Units Demo Container --- */
.units-demo-container {
  margin-top: 30px;
}

.units-demo-container section {
  background-color: white;
  border: 2px dashed #aaa;
  border-radius: 5px;
  padding: 20px;
  margin-bottom: 30px;
}

.units-demo-container h3 {
  color: #333;
  border-bottom: 2px solid #ddd;
  padding-bottom: 8px;
  margin-top: 0;
  margin-bottom: 15px;
}

/* px demo — fixed, never changes regardless of context */
.ud-px-box {
  width: 200px;
  height: 60px;
  background-color: #e0e0e0;
  font-size: 20px;
  padding: 10px;
  line-height: 40px;
  text-align: center;
}

/* em demo — relative to parent font-size; can compound when nested */
.ud-em-parent {
  font-size: 16px;
  background-color: #d1c4e9;
  padding: 10px;
  margin-bottom: 5px;
}

.ud-em-box {
  font-size: 1.5em;
  /* 1.5 × 16px = 24px */
  background-color: #b39ddb;
  padding: 8px;
}

.ud-em-child {
  font-size: 1.5em;
  /* 1.5 × 24px = 36px — compounds! */
  background-color: #9575cd;
  padding: 6px;
  color: white;
}

/* rem demo — always relative to the root <html> font-size (16px default) */
.ud-rem-box {
  font-size: 1.5rem;
  /* always 24px regardless of nesting depth */
  background-color: #c8e6c9;
  padding: 10px;
}

/* % demo — relative to the parent element's width/height */
.ud-pct-parent {
  background-color: #e0e0e0;
  padding: 10px;
}

.ud-pct-bar {
  width: 60%;
  /* 60% of parent container */
  background-color: #29b6f6;
  color: white;
  padding: 10px;
  text-align: center;
  font-weight: bold;
}

/* vw demo — relative to 1% of the viewport width */
.ud-vw-bar {
  width: 50vw;
  /* 50% of the browser window's width */
  background-color: #ff7043;
  color: white;
  padding: 10px;
  text-align: center;
  font-weight: bold;
}

/* vh demo — relative to 1% of the viewport height */
.ud-vh-box {
  height: 30vh;
  /* 30% of the browser window's height */
  background-color: #26a69a;
  color: white;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: bold;
  text-align: center;
  padding: 10px;
}

/* ========================================
   16. LESSON 10: ANIMATIONS
   ======================================== */

/* Override example-output for animation demos */
.lesson-10 .example-output {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 20px;
  min-height: 150px;
  align-items: center;
}

/* Animation demo box */
.lesson-10 .box {
  width: 100px;
  height: 100px;
  background-color: #f093fb;
  color: white;
  font-weight: bold;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  border-radius: 8px;
  cursor: pointer;
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

/* Transitions */
.trans-color {
  background-color: #4caf50;
  transition: background-color 0.5s ease;
}

.trans-color:hover {
  background-color: #ff5722;
}

.trans-transform {
  background-color: #2196f3;
  transition: transform 0.3s ease;
}

.trans-transform:hover {
  transform: scale(1.2) rotate(10deg);
}

/* Transforms */
.rotate-box:hover {
  transform: rotate(180deg);
  transition: transform 0.5s;
}

.scale-box:hover {
  transform: scale(0.5);
  transition: transform 0.5s;
}

/* Animations */
.anim-move {
  background-color: #34495e;
  animation: moveRight 2s ease-in-out infinite alternate;
}

@keyframes moveRight {
  from {
    transform: translateX(0);
  }

  to {
    transform: translateX(200px);
  }
}

.anim-spin {
  background-color: #ff9800;
  animation: spin 2s linear 0s infinite normal none;
}

@keyframes spin {
  0% {
    transform: rotate(0deg);
  }

  100% {
    transform: rotate(360deg);
  }
}

.anim-bounce {
  background-color: #9c27b0;
  animation: bounce 1s ease 0s infinite normal none;
}

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

  50% {
    transform: translateY(-30px);
  }
}

/* Loader */
.loader {
  border: 8px solid #f3f3f3;
  border-top: 8px solid #3498db;
  border-radius: 50%;
  width: 60px;
  height: 60px;
  animation: spin 1s linear 0s infinite normal none;
}

/* Flip Card */
.flip-card {
  background-color: transparent;
  width: 150px;
  height: 150px;
  perspective: 1000px;
}

.flip-inner {
  position: relative;
  width: 100%;
  height: 100%;
  text-align: center;
  transition: transform 0.6s;
  transform-style: preserve-3d;
}

.flip-card:hover .flip-inner {
  transform: rotateY(180deg);
}

.flip-front,
.flip-back {
  position: absolute;
  width: 100%;
  height: 100%;
  backface-visibility: hidden;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 10px;
  font-weight: bold;
  color: white;
}

.flip-front {
  background-color: #bbb;
  color: black;
}

.flip-back {
  background-color: #2980b9;
  transform: rotateY(180deg);
}

/* ========================================
   17. LESSON 11: POSITIONING
   ======================================== */

/* Positioning demo box */
.lesson-11 .box {
  width: 100px;
  height: 100px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-weight: bold;
  text-align: center;
  margin: 5px;
  border-radius: 5px;
  border: 2px solid rgba(0, 0, 0, 0.2);
  box-shadow: 2px 2px 5px rgba(0, 0, 0, 0.2);
}

/* Override example-output for positioning context */
.lesson-11 .example-output {
  position: relative;
  min-height: 200px;
}

/* Extra bottom padding for scrolling demos */
.lesson-11 {
  padding-bottom: 200px;
}

/* Static */
.static-box {
  position: static;
  background-color: #9e9e9e;
}

/* Relative */
.relative-box {
  position: relative;
  top: 20px;
  left: 20px;
  background-color: #2196f3;
  z-index: 10;
}

.normal-box {
  background-color: #ccc;
}

/* Absolute */
.relative-container {
  position: relative;
  height: 250px;
  border: 3px solid #e91e63;
  background-color: #fce4ec;
}

.absolute-tl {
  position: absolute;
  top: 0;
  left: 0;
  background-color: #e91e63;
}

.absolute-br {
  position: absolute;
  bottom: 10px;
  right: 10px;
  background-color: #e91e63;
}

.absolute-center {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  background-color: #880e4f;
}

/* Fixed */
.fixed-box {
  position: fixed;
  bottom: 20px;
  right: 20px;
  width: 150px;
  height: 60px;
  background-color: #ff5722;
  z-index: 1000;
  border: 4px solid white;
  box-shadow: 0 5px 15px rgba(0, 0, 0, 0.3);
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-weight: bold;
  border-radius: 5px;
}

/* Sticky */
.sticky-container {
  height: 300px;
  overflow-y: scroll;
  border: 3px solid #9c27b0;
}

.sticky-element {
  position: sticky;
  top: 0;
  width: 100%;
  height: 50px;
  background-color: #9c27b0;
  display: flex;
  align-items: center;
  padding-left: 20px;
  margin: 0;
  border-radius: 0;
  color: white;
  font-weight: bold;
}

.content-block {
  height: 800px;
  background: linear-gradient(#f3e5f5, #e1bee7);
  padding: 20px;
}

/* Z-Index */
.z-container {
  position: relative;
  height: 200px;
}

.z-1 {
  position: absolute;
  top: 20px;
  left: 20px;
  background-color: red;
  z-index: 1;
}

.z-2 {
  position: absolute;
  top: 50px;
  left: 50px;
  background-color: green;
  z-index: 2;
}

.z-3 {
  position: absolute;
  top: 80px;
  left: 80px;
  background-color: blue;
  z-index: 3;
}

/* ========================================
   18. LESSON 12: FLEXBOX
   ======================================== */

/* Scoped h3 styling for flexbox and grid lessons */
.lesson-12 h3,
.lesson-13 h3 {
  margin-top: 20px;
  margin-bottom: 5px;
  color: #555;
}

/* Flex Container */
.flex-container {
  display: flex;
  background-color: #e3f2fd;
  border: 2px solid #2196f3;
  padding: 10px;
  margin-bottom: 10px;
  min-height: 100px;
}

/* Flex Item */
.flex-container .item {
  background-color: #ff9800;
  color: white;
  font-weight: bold;
  padding: 15px;
  margin: 5px;
  text-align: center;
  border-radius: 4px;
  min-width: 50px;
}

.flex-container .item:nth-child(2) {
  background-color: #f57c00;
}

.flex-container .item:nth-child(3) {
  background-color: #e65100;
}

/* Flex Direction (renamed to avoid grid system .row conflict) */
.dir-row {
  flex-direction: row;
}

.dir-column {
  flex-direction: column;
}

/* Justify Content */
.j-start {
  justify-content: flex-start;
}

.j-center {
  justify-content: center;
}

.j-end {
  justify-content: flex-end;
}

.j-between {
  justify-content: space-between;
}

.j-around {
  justify-content: space-around;
}

/* Align Items */
.a-start {
  align-items: flex-start;
}

.a-center {
  align-items: center;
}

.a-end {
  align-items: flex-end;
}

.a-stretch {
  align-items: stretch;
  min-height: 120px;
}

/* Flex Wrap */
.wrap-container {
  display: flex;
  flex-wrap: wrap;
  width: 300px;
  background-color: #e8f5e9;
  border: 2px solid #4caf50;
  padding: 10px;
}

.wrap-item {
  width: 100px;
  height: 50px;
  background-color: #4caf50;
  color: white;
  margin: 5px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 4px;
}

/* Flex Grow */
.grow-container {
  display: flex;
  gap: 10px;
  background-color: #f3e5f5;
  padding: 10px;
}

.grow-1 {
  flex-grow: 1;
  background-color: #9c27b0;
  padding: 20px;
  color: white;
}

.grow-2 {
  flex-grow: 2;
  background-color: #7b1fa2;
  padding: 20px;
  color: white;
}

/* Demo Navbar (renamed to avoid grid system .navbar conflict) */
.demo-navbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  background-color: #333;
  color: white;
  padding: 10px 20px;
  border-radius: 5px;
}

.nav-menu {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  gap: 15px;
}

.nav-menu li {
  cursor: pointer;
}

.nav-menu li:hover {
  color: #ff9800;
}

/* Demo heights for align-items examples */
.demo-h-40 {
  height: 40px;
}

.demo-h-60 {
  height: 60px;
}

.demo-h-80 {
  height: 80px;
}

.demo-h-150 {
  height: 150px;
}

/* ========================================
   19. LESSON 13: CSS GRID
   ======================================== */

/* Grid Container */
.grid-container {
  display: grid;
  background-color: #fce4ec;
  border: 2px solid #e91e63;
  padding: 10px;
  margin-bottom: 10px;
  gap: 10px;
}

/* Grid Item */
.grid-container .item {
  background-color: #ec407a;
  color: white;
  font-weight: bold;
  padding: 20px;
  text-align: center;
  border-radius: 4px;
  font-size: 1.2rem;
}

.grid-container .item:nth-child(even) {
  background-color: #d81b60;
}

.grid-container .item:nth-child(3n) {
  background-color: #ad1457;
}

/* Basic Columns */
.cols-3 {
  grid-template-columns: 100px 100px 100px;
}

.cols-fr {
  grid-template-columns: 1fr 2fr 1fr;
}

/* Gap Demo */
.gap-demo {
  grid-template-columns: 1fr 1fr;
  gap: 20px;
}

/* Spanning */
.span-grid {
  grid-template-columns: repeat(3, 1fr);
}

.span-col-2 {
  grid-column: span 2;
  background-color: #880e4f;
}

.span-row-2 {
  grid-row: span 2;
  background-color: #880e4f;
  display: flex;
  align-items: center;
  justify-content: center;
}

/* Grid Areas (Dashboard) */
.dashboard {
  display: grid;
  height: 400px;
  grid-template-columns: 200px 1fr 1fr;
  grid-template-rows: 60px 1fr 100px 60px;
  gap: 10px;
  grid-template-areas:
    "header header header"
    "nav main main"
    "nav widget1 widget2"
    "footer footer footer";
  color: white;
  font-weight: bold;
  font-size: 1.2rem;
  text-align: center;
}

.area-header {
  grid-area: header;
  background-color: #1a237e;
}

.area-nav {
  grid-area: nav;
  background-color: #283593;
}

.area-main {
  grid-area: main;
  background-color: #3949ab;
}

.area-widget1 {
  grid-area: widget1;
  background-color: #5c6bc0;
}

.area-widget2 {
  grid-area: widget2;
  background-color: #7986cb;
}

.area-footer {
  grid-area: footer;
  background-color: #303f9f;
}

/* ========================================
   20. LESSON 13: RESPONSIVE DESIGN
   ======================================== */

/* Viewport Demo */
.vw-box {
  background-color: #00acc1;
  width: 50vw;
  color: white;
  padding: 10px;
  margin-bottom: 5px;
}

.pct-box {
  background-color: #00838f;
  width: 50%;
  color: white;
  padding: 10px;
}

/* Media Query Demo */
.responsive-box {
  background-color: #ff5722;
  color: white;
  padding: 20px;
  text-align: center;
  font-weight: bold;
  transition: background-color 0.3s;
}

/* Responsive Grid Layout */
.responsive-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 10px;
}

.grid-card {
  background-color: #673ab7;
  color: white;
  padding: 20px;
  text-align: center;
}

/* Hide/Show Demo */
.mobile-only {
  display: block;
  background-color: #e91e63;
  color: white;
  padding: 10px;
  text-align: center;
}

.desktop-only {
  display: none;
  background-color: #3f51b5;
  color: white;
  padding: 10px;
  text-align: center;
}

/* Clamp Demo */
.clamp-demo {
  font-size: clamp(1rem, 5vw, 3rem);
  text-align: center;
  transition: font-size 0.2s;
}

/* ========================================
   21. RESPONSIVE MEDIA QUERIES
   ======================================== */

/* Tablet breakpoint - responsive design demos */
@media (min-width: 600px) {
  .responsive-box {
    background-color: #2196f3;
  }

  .responsive-box::after {
    content: " (Tablet View >= 600px)";
  }

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

/* Desktop breakpoint - responsive design demos */
@media (min-width: 768px) {
  .mobile-only {
    display: none;
  }

  .desktop-only {
    display: block;
  }
}

/* Desktop breakpoint - responsive design demos */
@media (min-width: 900px) {
  .responsive-box {
    background-color: #4caf50;
  }

  .responsive-box::after {
    content: " (Desktop View >= 900px)";
  }

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

/* Dashboard responsive - stack on small screens */
@media (max-width: 768px) {
  .dashboard {
    grid-template-columns: 1fr;
    grid-template-rows: auto;
    height: auto;
    grid-template-areas:
      "header"
      "nav"
      "main"
      "widget1"
      "widget2"
      "footer";
  }
}

/* --- 04: Text Overflow --- */
.demo.ov-clip {
  max-width: 300px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: clip;
}

.demo.ov-ellipsis {
  max-width: 300px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.demo.clamp-2 {
  max-width: 350px;
  display: -webkit-box;
  -webkit-box-orient: vertical;
  -webkit-line-clamp: 2;
  overflow: hidden;
}

.demo.clamp-4 {
  max-width: 350px;
  display: -webkit-box;
  -webkit-box-orient: vertical;
  -webkit-line-clamp: 4;
  overflow: hidden;
}

.demo.wrap-normal {
  max-width: 250px;
  border: 1px solid #ccc;
  overflow-wrap: normal;
}

.demo.wrap-anywhere {
  max-width: 250px;
  border: 1px solid #ccc;
  overflow-wrap: anywhere;
}