/* ========================================
   DE Curriculum — Educational Theme
   Clean light mode + Immersive dark mode
   ======================================== */

/* --- CSS Variables --- */
:root {
    --de-gold: #C9A227;
    --de-gold-light: #E5C04B;
    --de-gold-dark: #A68B1E;
    --de-gold-muted: rgba(201, 162, 39, 0.08);
    
    /* Light mode palette — Espresso */
    --de-light-bg: #F5F0EB;              /* Warm cream background */
    --de-light-surface: #FFFFFF;         /* Pure white cards */
    --de-light-text: #2C1810;            /* Dark espresso text */
    --de-light-text-muted: #5C4033;      /* Medium roast muted */
    --de-light-accent: #6F4E37;          /* Coffee brown links */
    --de-light-accent-hover: #4A3728;    /* Darker espresso hover */
    --de-light-border: #D4C4B0;          /* Latte borders */
    --de-light-code-bg: #EDE4DA;         /* Cream code blocks */
    
    /* Dark mode palette */
    --de-dark-bg: #0F0F1A;
    --de-dark-surface: #1A1A2E;
    --de-dark-text: #E8E8F0;
    --de-dark-text-muted: #A0A0B8;
    --de-dark-accent: #E5C04B;         /* Gold for dark mode links */
    --de-dark-border: #2A2A40;
}

/* --- Light Mode (Espresso) --- */
[data-md-color-scheme="default"] {
    --md-primary-fg-color: #2C1810;
    --md-primary-fg-color--light: #4A3728;
    --md-primary-fg-color--dark: #1A0E0A;
    --md-primary-bg-color: var(--de-light-bg);
    --md-primary-bg-color--light: var(--de-light-surface);
    --md-accent-fg-color: var(--de-gold);
    --md-accent-fg-color--transparent: var(--de-gold-muted);
    --md-default-bg-color: var(--de-light-bg);
    --md-default-bg-color--light: var(--de-light-surface);
    --md-typeset-a-color: var(--de-light-accent);
    --md-footer-bg-color: #2C1810;
    --md-footer-bg-color--dark: #1A0E0A;
    --md-typeset-color: var(--de-light-text);
    --md-default-fg-color: var(--de-light-text);
    --md-default-fg-color--light: var(--de-light-text-muted);
}

/* --- Dark Mode --- */
[data-md-color-scheme="slate"] {
    --md-primary-fg-color: #0D0D1A;
    --md-primary-fg-color--light: #1A1A2E;
    --md-primary-fg-color--dark: #05050F;
    --md-accent-fg-color: var(--de-gold);
    --md-accent-fg-color--transparent: rgba(201, 162, 39, 0.1);
    --md-default-bg-color: var(--de-dark-bg);
    --md-default-bg-color--light: var(--de-dark-surface);
    --md-typeset-a-color: var(--de-dark-accent);
    --md-typeset-color: var(--de-dark-text);
    --md-default-fg-color: var(--de-dark-text);
    --md-default-fg-color--light: var(--de-dark-text-muted);
}

/* --- Base Typography --- */
.md-typeset {
    color: var(--md-typeset-color);
    line-height: 1.7;
}

/* --- Links --- */
.md-typeset a {
    color: var(--md-typeset-a-color);
    text-decoration: none;
    transition: color 0.15s;
}

.md-typeset a:hover {
    color: var(--de-gold);
    text-decoration: underline;
    text-decoration-color: var(--de-gold-muted);
}

/* --- Header --- */
[data-md-color-scheme="default"] .md-header {
    background: rgba(44, 24, 16, 0.97);
}

[data-md-color-scheme="slate"] .md-header {
    background: rgba(13, 13, 26, 0.97);
}

.md-header__source {
    color: var(--de-gold);
}

/* --- Sidebar --- */
.md-nav__link {
    transition: color 0.15s, padding-left 0.15s, background-color 0.15s;
    border-radius: 6px;
    padding-left: 0.5rem;
    color: var(--md-default-fg-color--light);
}

.md-nav__link:hover {
    color: var(--de-gold);
    background-color: var(--de-gold-muted);
}

.md-nav__link--active {
    color: var(--de-gold) !important;
    font-weight: 600;
    background-color: var(--de-gold-muted);
}

/* Unit section headers */
.md-nav__item--section > .md-nav__link {
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    font-size: 0.8rem;
    color: var(--de-gold);
}

/* --- Headers (h1, h2, h3) --- */
.md-typeset h1 {
    color: var(--de-gold);
    font-weight: 700;
    border-bottom: 2px solid var(--de-light-border);
    padding-bottom: 0.5rem;
    margin-bottom: 1.5rem;
}

[data-md-color-scheme="slate"] .md-typeset h1 {
    border-bottom-color: var(--de-dark-border);
}

.md-typeset h2 {
    color: var(--de-light-accent);
    font-weight: 600;
    margin-top: 2.5rem;
    padding-top: 1rem;
    border-top: 1px solid var(--de-light-border);
}

[data-md-color-scheme="slate"] .md-typeset h2 {
    color: var(--de-gold);
    border-top-color: var(--de-dark-border);
}

/* --- Paragraph spacing --- */
.md-typeset p {
    margin-bottom: 1rem;
}

/* --- Tables --- */
.md-typeset table:not([class]) {
    font-size: 0.9rem;
    border-collapse: separate;
    border-spacing: 0;
}

.md-typeset table:not([class]) td,
.md-typeset table:not([class]) th {
    padding: 0.6rem 0.8rem;
}

.md-typeset table:not([class]) th {
    background-color: var(--de-gold);
    color: #1a1a2e;
    font-weight: 700;
    text-transform: uppercase;
    font-size: 0.75rem;
    letter-spacing: 0.04em;
}

[data-md-color-scheme="slate"] .md-typeset table:not([class]) th {
    color: #0F0F1A;
}

/* --- Admonitions --- */
.md-typeset .admonition {
    border-left: 3px solid var(--de-gold);
    border-radius: 0 8px 8px 0;
    margin: 1rem 0;
}

[data-md-color-scheme="default"] .md-typeset .admonition {
    background-color: var(--de-gold-muted);
}

.md-typeset .admonition-title {
    background-color: var(--de-gold);
    color: #1a1a2e;
    font-weight: 700;
    text-transform: uppercase;
    font-size: 0.8rem;
    letter-spacing: 0.03em;
}

/* --- Collapsible Details --- */
.md-typeset details {
    border-left: 3px solid var(--de-gold);
    border-radius: 0 8px 8px 0;
}

[data-md-color-scheme="default"] .md-typeset details {
    background-color: rgba(201, 162, 39, 0.05);
}

.md-typeset details summary {
    color: var(--de-light-accent);
    font-weight: 600;
    cursor: pointer;
}

[data-md-color-scheme="slate"] .md-typeset details summary {
    color: var(--de-gold);
}

/* --- Code Blocks --- */
.md-typeset pre {
    margin: 1rem 0;
}

[data-md-color-scheme="default"] .md-typeset pre > code {
    background-color: var(--de-light-code-bg);
    border: 1px solid var(--de-light-border);
}

[data-md-color-scheme="slate"] .md-typeset pre > code {
    background-color: rgba(26, 26, 46, 0.8);
    border: 1px solid var(--de-dark-border);
}

/* --- Blockquotes --- */
.md-typeset blockquote {
    border-left: 3px solid var(--de-gold);
    border-radius: 0 8px 8px 0;
    background-color: var(--de-gold-muted);
    font-style: italic;
}

.md-typeset blockquote strong {
    color: var(--de-gold-dark);
    font-style: normal;
}

[data-md-color-scheme="slate"] .md-typeset blockquote strong {
    color: var(--de-gold);
}

/* --- Unit Cards (Homepage) --- */
.unit-card {
    display: block;
    padding: 1.75rem;
    margin-bottom: 1.25rem;
    border: 1px solid var(--de-light-border);
    border-radius: 12px;
    background: var(--de-light-surface);
    transition: transform 0.2s, box-shadow 0.2s, border-color 0.2s;
    text-decoration: none;
    color: inherit;
}

[data-md-color-scheme="slate"] .unit-card {
    border-color: var(--de-dark-border);
    background: var(--de-dark-surface);
}

.unit-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 20px rgba(201, 162, 39, 0.1);
    border-color: var(--de-gold);
}

.unit-card h3 {
    color: var(--de-gold);
    margin-top: 0;
    margin-bottom: 0.5rem;
}

.unit-card p {
    margin-bottom: 0;
    color: var(--md-default-fg-color--light);
    line-height: 1.6;
}

/* --- Quiz Styles --- */
.quiz-container {
    margin: 2rem 0;
    padding: 1.5rem;
    border: 1px solid var(--de-light-border);
    border-radius: 12px;
    background: var(--de-light-surface);
}

[data-md-color-scheme="slate"] .quiz-container {
    border-color: var(--de-dark-border);
    background: var(--de-dark-surface);
}

.quiz-container .quiz-title {
    font-size: 1rem;
    font-weight: 700;
    color: var(--de-gold);
    margin-bottom: 1rem;
}

.quiz-option {
    display: block;
    padding: 0.75rem 1rem;
    margin: 0.5rem 0;
    border: 1px solid var(--de-light-border);
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.15s;
    background: transparent;
}

[data-md-color-scheme="slate"] .quiz-option {
    border-color: var(--de-dark-border);
}

.quiz-option:hover {
    border-color: var(--de-gold);
    background-color: var(--de-gold-muted);
}

.quiz-option.correct {
    border-color: #22c55e;
    background-color: rgba(34, 197, 94, 0.1);
}

.quiz-option.incorrect {
    border-color: #ef4444;
    background-color: rgba(239, 68, 68, 0.1);
}

/* --- Glossary --- */
.glossary-letter {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--de-gold);
    border-bottom: 1px solid var(--de-light-border);
    margin-top: 2rem;
    margin-bottom: 1rem;
    padding-bottom: 0.5rem;
}

[data-md-color-scheme="slate"] .glossary-letter {
    border-bottom-color: var(--de-dark-border);
}

.glossary-term {
    margin-bottom: 0.75rem;
    padding: 0.5rem 0.75rem;
    border-radius: 6px;
    background-color: var(--de-gold-muted);
}

.glossary-term dt {
    font-weight: 700;
    color: var(--de-gold-dark);
}

[data-md-color-scheme="slate"] .glossary-term dt {
    color: var(--de-gold);
}

/* --- Footer --- */
.md-footer {
    color: var(--de-dark-text-muted);
}

.md-footer a {
    color: var(--de-gold);
}

/* --- Print Styles --- */
@media print {
    .md-sidebar, .md-header, .md-footer, .md-search {
        display: none !important;
    }
    
    .md-content {
        margin: 0 !important;
        max-width: 100% !important;
    }
    
    a {
        color: #000 !important;
    }
    
    .md-typeset .admonition-title {
        background-color: #000 !important;
        color: #fff !important;
    }
}

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

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

::-webkit-scrollbar-thumb {
    background: rgba(201, 162, 39, 0.3);
    border-radius: 3px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--de-gold);
}

/* ========================================
   Lesson Components — Tags, Prereqs, Related
   ======================================== */

/* --- Topic Tags --- */
.lesson-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.4rem;
    margin-bottom: 1rem;
}

.lesson-tag {
    display: inline-block;
    padding: 0.15rem 0.6rem;
    font-size: 0.75rem;
    font-weight: 600;
    border: 1px solid var(--de-gold);
    border-radius: 999px;
    color: var(--de-gold-dark);
    background: var(--de-gold-muted);
    letter-spacing: 0.02em;
}

[data-md-color-scheme="slate"] .lesson-tag {
    color: var(--de-gold);
    border-color: rgba(201, 162, 39, 0.4);
    background: rgba(201, 162, 39, 0.1);
}

/* --- Prerequisites Box --- */
.lesson-prerequisites {
    padding: 0.75rem 1rem;
    margin-bottom: 1rem;
    border-left: 3px solid #3b82f6;
    border-radius: 0 8px 8px 0;
    background: rgba(59, 130, 246, 0.06);
}

[data-md-color-scheme="slate"] .lesson-prerequisites {
    background: rgba(59, 130, 246, 0.08);
    border-left-color: #60a5fa;
}

.lesson-prerequisites__label {
    font-weight: 700;
    font-size: 0.8rem;
    text-transform: uppercase;
    letter-spacing: 0.03em;
    color: #3b82f6;
    margin-right: 0.5rem;
}

[data-md-color-scheme="slate"] .lesson-prerequisites__label {
    color: #60a5fa;
}

.lesson-prerequisites__list {
    display: inline;
    list-style: none;
    padding: 0;
    margin: 0;
}

.lesson-prerequisites__list li {
    display: inline;
}

.lesson-prerequisites__list li:not(:last-child)::after {
    content: ", ";
}

.lesson-prerequisites__link {
    color: #3b82f6;
    text-decoration: none;
}

.lesson-prerequisites__link:hover {
    text-decoration: underline;
}

[data-md-color-scheme="slate"] .lesson-prerequisites__link {
    color: #60a5fa;
}

/* --- Related Lessons Footer --- */
.related-lessons {
    margin-top: 2rem;
    padding-top: 1rem;
    border-top: 1px solid var(--de-light-border);
}

[data-md-color-scheme="slate"] .related-lessons {
    border-top-color: var(--de-dark-border);
}

.related-lessons__label {
    display: block;
    font-weight: 700;
    font-size: 0.8rem;
    text-transform: uppercase;
    letter-spacing: 0.03em;
    color: var(--md-default-fg-color--light);
    margin-bottom: 0.5rem;
}

.related-lessons__links {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.related-link {
    display: inline-block;
    padding: 0.3rem 0.75rem;
    font-size: 0.85rem;
    border-radius: 6px;
    text-decoration: none;
    font-weight: 500;
    transition: transform 0.15s, box-shadow 0.15s;
}

.related-link:hover {
    transform: translateY(-1px);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    text-decoration: none;
}

.related-link--next {
    background: var(--de-gold-muted);
    color: var(--de-gold-dark);
    border: 1px solid var(--de-gold);
}

[data-md-color-scheme="slate"] .related-link--next {
    color: var(--de-gold);
    border-color: rgba(201, 162, 39, 0.4);
}

.related-link--prereq {
    background: rgba(59, 130, 246, 0.08);
    color: #3b82f6;
    border: 1px solid #3b82f6;
}

[data-md-color-scheme="slate"] .related-link--prereq {
    color: #60a5fa;
    border-color: rgba(96, 165, 250, 0.4);
    background: rgba(59, 130, 246, 0.1);
}

.related-link--applies {
    background: rgba(168, 85, 247, 0.08);
    color: #7c3aed;
    border: 1px solid #7c3aed;
}

[data-md-color-scheme="slate"] .related-link--applies {
    color: #a78bfa;
    border-color: rgba(167, 139, 250, 0.4);
    background: rgba(168, 85, 247, 0.1);
}

/* ========================================
   Progress System — Sidebar & Bars
   ======================================== */

/* --- Sidebar Progress Indicators --- */
.nav-lesson--viewed {
    position: relative;
}

.nav-lesson--viewed::before {
    content: "\2713";
    position: absolute;
    left: -0.2rem;
    color: #22c55e;
    font-size: 0.7rem;
    font-weight: 700;
}

.nav-lesson--current {
    border-left: 2px solid var(--de-gold);
    padding-left: 0.5rem;
}

/* --- Progress Bars --- */
.unit-progress {
    margin-top: 0.5rem;
    font-size: 0.75rem;
    color: var(--md-default-fg-color--light);
}

.unit-progress__bar {
    height: 4px;
    background: var(--de-dark-border);
    border-radius: 2px;
    margin-top: 0.25rem;
    overflow: hidden;
}

[data-md-color-scheme="default"] .unit-progress__bar {
    background: var(--de-light-border);
}

.unit-progress__fill {
    height: 100%;
    background: var(--de-gold);
    border-radius: 2px;
    transition: width 0.3s ease;
}

/* --- Continue Learning Card --- */
.continue-card {
    display: block;
    padding: 1.25rem 1.5rem;
    margin-bottom: 1.5rem;
    border: 2px solid var(--de-gold);
    border-radius: 12px;
    background: var(--de-gold-muted);
    text-decoration: none;
    color: inherit;
    transition: transform 0.2s, box-shadow 0.2s;
}

.continue-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 20px rgba(201, 162, 39, 0.15);
    text-decoration: none;
}

.continue-card__title {
    font-size: 0.8rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.04em;
    color: var(--de-gold-dark);
    margin: 0 0 0.25rem 0;
}

[data-md-color-scheme="slate"] .continue-card__title {
    color: var(--de-gold);
}

.continue-card__lesson {
    font-size: 1rem;
    font-weight: 600;
    color: var(--md-typeset-color);
    margin: 0;
}

/* --- Course Progress Stat --- */
.course-progress {
    margin: 1.5rem 0;
    padding: 1rem;
    border-radius: 8px;
    background: var(--de-gold-muted);
    text-align: center;
}

.course-progress__stat {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--de-gold);
}

.course-progress__label {
    font-size: 0.85rem;
    color: var(--md-default-fg-color--light);
}

/* ========================================
   Video Embed — Responsive YouTube
   ======================================== */

.video-embed {
    position: relative;
    margin: 1.5rem 0;
    border: 1px solid var(--de-light-border);
    border-radius: 12px;
    overflow: hidden;
    background: var(--de-light-surface);
}

[data-md-color-scheme="slate"] .video-embed {
    border-color: var(--de-dark-border);
    background: var(--de-dark-surface);
}

.video-embed__wrapper {
    position: relative;
    width: 100%;
    padding-bottom: 56.25%;
    background: #000;
}

.video-embed__wrapper iframe,
.video-embed__wrapper img {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    border: none;
}

.video-embed__placeholder {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    background-size: cover;
    background-position: center;
    background-color: #1a1a2e;
}

.video-embed__play-btn {
    width: 68px;
    height: 48px;
    background-color: rgba(201, 162, 39, 0.9);
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: transform 0.15s, background-color 0.15s;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
}

.video-embed__play-btn::after {
    content: "";
    display: block;
    width: 0;
    height: 0;
    border-style: solid;
    border-width: 10px 0 10px 18px;
    border-color: transparent transparent transparent #1a1a2e;
    margin-left: 3px;
}

.video-embed__placeholder:hover .video-embed__play-btn {
    transform: scale(1.08);
    background-color: var(--de-gold);
}

.video-embed__title {
    padding: 0.5rem 0.75rem;
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--md-default-fg-color--light);
}

[data-md-color-scheme="slate"] .video-embed__title {
    color: var(--de-dark-text-muted);
}

@media (prefers-reduced-motion: reduce) {
    .video-embed__play-btn {
        transition: none;
    }
}

@media (max-width: 600px) {
    .video-embed {
        margin-left: -0.5rem;
        margin-right: -0.5rem;
        border-radius: 8px;
    }
}

/* ========================================
   Section Labels — Lesson Headings
   ======================================== */

/* Section labels for headings with data-section attribute */
[data-section]::before {
    content: attr(data-section);
    display: block;
    font-size: 0.65rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--md-default-fg-color--light);
    margin-bottom: 0.15rem;
    opacity: 0.7;
}

/* Override content for specific section types */
[data-section="objectives"]::before {
    content: "OBJECTIVES";
}

[data-section="vocabulary"]::before {
    content: "VOCABULARY";
}

[data-section="part"]::before {
    content: "SECTION";
}

[data-section="summary"]::before {
    content: "SUMMARY";
}

[data-section="reminders"]::before {
    content: "KEY REMINDERS";
}

[data-section="practice"]::before {
    content: "PRACTICE";
}

/* Special styling for part sections */
[data-section="part"] {
    border-left: 3px solid var(--de-gold);
    padding-left: 0.75rem;
}