/* CSS Reset and Global Styles */
* {
  box-sizing: border-box;
}

*:before,
*:after {
  box-sizing: inherit;
}

/* CSS Variables */
:root {
  /* Color palette */
  --white: #fff;

  /* Neutrals */
  --light-grey-1: #F5F7FA;
  --light-grey-2: #E4E7EB;
  --light-grey-3: #CBD2D9;
  --light-grey-4: #9AA5B1;
  --light-grey-5: #7B8794;

  --grey-1: #616E7C;
  --grey-2: #52606D;
  --grey-3: #3E4C59;
  --grey-4: #323F4B;
  --grey-5: #1F2933;

  /* Main: Indigo */
  --light-indigo-1: #E0E8F9;
  --light-indigo-2: #BED0F7;
  --light-indigo-3: #98AEEB;
  --light-indigo-4: #7B93DB;
  --light-indigo-5: #647ACB;

  --indigo-1: #4C63B6;
  --indigo-2: #4055A8;
  --indigo-3: #35469C;
  --indigo-4: #2D3A8C;
  --indigo-5: #19216C;

  /* Spacing */
  --spacing-2xs: 4px;
  --spacing-xs: 8px;
  --spacing-sm: 12px;
  --spacing-md: 16px;
  --spacing-lg: 24px;
  --spacing-xl: 32px;
  --spacing-2xl: 48px;
  --spacing-3xl: 64px;
  --spacing-4xl: 128px;

  /* Text sizes */
  --text-2xs: 10px;
  --text-xs: 12px;
  --text-sm: 14px;
  --text-md: 16px;
  --text-lg: 18px;
  --text-xl: 20px;
  --text-2xl: 24px;
  --text-3xl: 30px;
  --text-4xl: 36px;
  --text-5xl: 48px;

  --background-color: white;
  --font-family: "Inter", -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
  --font-family-monospace: 'Fira Mono', 'Courier New', Courier, monospace;
  --text-color: var(--grey-5);
  --light-text-color: var(--light-grey-5);
  --link-color: var(--indigo-1);
  --base-font-size: var(--text-md);
  --border-radius: 4px;
  --border-color: var(--light-indigo-2);
  --box-shadow: 0 1px 5px rgba(0, 0, 0, .2);
  --line-height: 1.77;

  --button-bg: var(--light-indigo-5);
  --button-bg-hover: var(--light-indigo-4);
  --button-color: var(--white);
  --button-border-radius: var(--border-radius);
  --button-padding: var(--spacing-xs) var(--spacing-md);

  --header-height: 50px;
  --header-bg: var(--indigo-2);
}

html {
  font-family: var(--font-family);
  box-sizing: border-box;
  font-size: var(--base-font-size);
}

body {
  background-color: var(--background-color);
  color: var(--text-color);
  overscroll-behavior: none;
  transition: all 0.2s;
  margin: 0;
  padding: 0;
}

h1, h2, h3, h4, h5, h6 {
  font-weight: normal;
  line-height: 1.5;
}

h1, h2, h3, h4 {
  font-weight: 600;
}

a {
  color: var(--link-color);
  text-decoration: none;
}

p, ul, ol {
  line-height: 1.77;
  font-weight: 400;
}

p:first-child {
  margin-top: 0;
}

button {
  padding: 0;
  background: none;
  outline: none;
  border: none;
  cursor: pointer;
  color: var(--text-color);
}

strong {
  font-weight: 600;
}

/* Header */
.header {
  height: var(--header-height);
  padding: 0 var(--spacing-lg);
  background: var(--header-bg);
  color: var(--white);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.logo {
  font-weight: 600;
}

.header nav ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
}

.header nav a {
  color: var(--white);
  text-decoration: none;
}

/* Dropzone */
.dropzone-wrapper {
  position: relative;
  z-index: 0;
}

.dropzone-alert {
  display: none;
  background-color: rgba(52, 177, 235, 0.2);
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  text-align: center;
  pointer-events: none;
  z-index: 1000;
  border: 5px var(--light-indigo-4) solid;
}

.dropzone-alert.active {
  display: block;
}

.dropzone-uploading {
  display: none;
  background-color: rgba(202, 100, 235, 0.5);
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  text-align: center;
  pointer-events: none;
  z-index: 1000;
}

.dropzone-uploading.active {
  display: block;
}

.dropzone-message {
  position: relative;
  top: 50%;
  transform: translateY(-50%);
}

/* Main Grid Layout */
.book-app-wrapper {
  min-height: calc(100vh - var(--header-height));
  max-height: calc(100vh - var(--header-height));
  padding: 0;
  max-width: 100%;
  margin: 0 auto;

  display: grid;
  grid-template-areas:
    "instructions highlights export"
    "preset highlights export"
    "footer footer footer";

  grid-template-columns: minmax(150px, 400px) minmax(200px, 1fr) minmax(300px, 1fr);
  grid-template-rows: 1fr 1fr auto;

  font-size: var(--text-xs);
}

@media (max-width: 1020px) {
  .book-app-wrapper {
    grid-template-areas:
      "instructions highlights"
      "preset export"
      "footer footer";

    grid-template-columns: minmax(150px, 300px) minmax(200px, 1fr);
  }
}

@media (max-width: 850px) {
  .book-app-wrapper {
    grid-template-areas:
      "instructions"
      "highlights"
      "export"
      "preset"
      "footer";

    grid-template-columns: 1fr;
    grid-template-rows: auto minmax(200px, auto) minmax(200px, auto) auto auto;
    max-height: auto;
  }
}

/* Area Base Styles */
.area {
  overflow: hidden;
  display: flex;
  flex-direction: column;
}

.area-title {
  font-weight: 600;
  border-bottom: 1px var(--border-color) solid;
  text-align: left;
  margin: 0;
  padding: var(--spacing-sm) var(--spacing-lg);
  background: var(--light-indigo-1);
  z-index: 100;
  display: flex;
  justify-content: space-between;
  font-size: var(--text-sm);
}

.area-content {
  overflow-y: auto;
  -ms-overflow-style: -ms-autohiding-scrollbar;
  position: relative;
  flex: 1;
}

/* Instructions Area */
.instructions-area {
  grid-area: instructions;
  border-right: 1px var(--border-color) solid;
}

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

.instructions-section input[type="file"] {
  display: none;
}

.instructions-section ol {
  margin: 0;
  margin-bottom: var(--spacing-xl);
  padding: var(--spacing-sm);
}

/* Highlights Area */
.highlights-area {
  grid-area: highlights;
  border-right: 1px var(--border-color) solid;
}

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

.book-heading {
  margin-bottom: var(--spacing-2xl);
}

.book-title {
  margin: 0;
  font-size: var(--text-xl);
}

.book-authors {
  margin-top: var(--spacing-sm);
}

.section {
  margin-bottom: var(--spacing-2xl);
}

.section-title {
  margin: 0;
  font-size: var(--text-lg);
  position: sticky;
  top: 0;
  background: var(--background-color);
  padding: var(--spacing-md) 0;
}

.highlight {
  margin-bottom: var(--spacing-lg);
}

.highlight-content {
  margin-bottom: 0;
}

.highlight-meta {
  margin-top: var(--spacing-2xs);
  color: var(--light-text-color);
}

.highlight-meta span {
  margin-right: var(--spacing-sm);
}

/* Export Area */
.export-area {
  grid-area: export;
}

.export-textarea {
  display: block;
  position: absolute;
  left: 0;
  right: 0;
  top: 0;
  bottom: 0;
  width: 100%;
  height: 100%;
  padding: var(--spacing-lg);
  line-height: var(--line-height);
  border: none;
  outline: none;
  font-family: var(--font-family-monospace);
  resize: none;
}

.presets-wrapper {
  display: flex;
}

.preset-button {
  margin-left: var(--spacing-sm);
  color: var(--light-text-color);
  position: relative;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0;
  font-size: inherit;
}

.preset-button.active {
  color: var(--grey-4);
}

.preset-button.active::after {
  display: block;
  content: "";
  height: 2px;
  background-color: var(--grey-4);
  position: absolute;
  top: calc(100% + 4px);
  left: 0;
  right: 0;
}

/* Custom Preset Area */
.custom-preset-area {
  grid-area: preset;
  border-right: 1px var(--border-color) solid;
  border-top: 1px var(--border-color) solid;
}

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

.custom-preset-section textarea {
  border: 1px var(--border-color) solid;
  padding: var(--spacing-sm);
  display: block;
  margin: var(--spacing-lg) 0;
  width: 100%;
  font-family: var(--font-family-monospace);
  line-height: var(--line-height);
  outline: none;
  resize: vertical;
}

/* Button Styles */
.btn-primary {
  cursor: pointer;
  background-color: var(--button-bg);
  color: var(--button-color);
  outline: none;
  padding: var(--button-padding);
  border-radius: var(--button-border-radius);
  border: none;
  text-align: center;
  user-select: none;
  font-size: var(--text-sm);
  transition: all 0.3s ease-in-out;
  display: inline-block;
}

.btn-primary:hover {
  background: var(--button-bg-hover);
}

/* Footer */
.footer {
  grid-area: footer;
  padding: var(--spacing-sm) var(--spacing-lg);
  border-top: 1px var(--border-color) solid;
  background: var(--light-indigo-1);
  display: flex;
  justify-content: space-between;
}