/**
 * Full Stack Course Template - Shared Styles
 *
 * This provides the unified styling for all courses including:
 * - Collapsible sidebar (50px → 280px on hover)
 * - Sticky positioning for sidebar
 * - Navigation styles
 * - Card and widget styles
 * - Quiz system
 * - Info/warning boxes
 * - Code blocks
 * - Responsive design
 *
 * Include after shared.css and before course-specific styles.
 */

/* =====================================================
   CSS VARIABLES - Override these in course-specific CSS
   ===================================================== */
:root {
    /* Core colors - can be overridden per course */
    --course-bg-primary: #0a0a0f;
    --course-bg-secondary: #12121a;
    --course-bg-card: #16161f;
    --course-bg-code: #0d0d12;
    --course-border: #2a2a3a;
    --course-text-primary: #f0f0f5;
    --course-text-secondary: #a0a0b8;
    --course-text-muted: #6a6a7a;
    --course-accent: #00ff41;
    --course-accent-secondary: #00cc33;
    --course-accent-orange: #d29922;
    --course-accent-red: #f85149;
    --course-accent-purple: #a371f7;

    /* Layout */
    --sidebar-collapsed: 50px;
    --sidebar-expanded: 280px;
    --content-max-width: 65ch;
    --header-height: auto;
}

/* =====================================================
   BASE RESET & TYPOGRAPHY
   ===================================================== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

::-webkit-scrollbar {
    width: 10px;
    height: 10px;
}

::-webkit-scrollbar-track {
    background: var(--course-bg-secondary);
}

::-webkit-scrollbar-thumb {
    background: #3a3a4a;
    border-radius: 5px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--course-text-secondary);
}

body {
    font-family: 'DM Sans', 'Inter', system-ui, sans-serif;
    background: var(--course-bg-primary);
    color: var(--course-text-primary);
    min-height: 100vh;
    line-height: 1.7;
}

a {
    color: var(--course-accent-secondary);
    text-decoration: none;
}

a:hover {
    color: var(--course-accent);
    text-decoration: underline;
}

/* =====================================================
   GRID BACKGROUND (optional decorative element)
   ===================================================== */
.grid-bg {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-image:
        linear-gradient(var(--course-border) 1px, transparent 1px),
        linear-gradient(90deg, var(--course-border) 1px, transparent 1px);
    background-size: 60px 60px;
    opacity: 0.08;
    pointer-events: none;
    z-index: -1;
}

/* =====================================================
   HEADER
   ===================================================== */
header {
    position: relative;
    padding: 1.5rem 2rem;
    border-bottom: 1px solid var(--course-border);
    display: flex;
    align-items: center;
    justify-content: space-between;
    background: var(--course-bg-secondary);
}

.back-link {
    color: var(--course-text-muted);
    text-decoration: none;
    font-size: 0.9rem;
    transition: color 0.15s;
}

.back-link:hover {
    color: var(--course-accent);
    text-decoration: none;
}

.header-brand h1 {
    font-size: 2rem;
    font-weight: 600;
    margin: 0;
    line-height: 1;
}

.header-brand h1 span {
    color: var(--course-accent);
}

.tagline {
    color: var(--course-text-secondary);
    font-size: 0.85rem;
    margin: 0.25rem 0 0 0;
}

/* Header auth section */
.header-auth {
    flex-shrink: 0;
    visibility: hidden;
}

.header-auth.ready {
    visibility: visible;
}

.progress-warning {
    display: flex;
    flex-direction: column;
    font-family: inherit;
    font-size: inherit;
    align-items: flex-end;
    gap: 0.15rem;
    background: rgba(251, 191, 36, 0.1);
    border: 1px solid rgba(251, 191, 36, 0.3);
    border-radius: 6px;
    padding: 0.5rem 0.75rem;
    font-size: 0.75rem;
    color: #fbbf24;
    cursor: pointer;
    transition: all 0.2s;
    text-align: right;
}

.progress-warning:hover {
    background: rgba(251, 191, 36, 0.15);
    border-color: rgba(251, 191, 36, 0.5);
}

.progress-warning-line1 {
    white-space: nowrap;
}

.progress-warning-cta {
    color: var(--course-accent);
    font-weight: 500;
    font-size: 0.8rem;
}

#progress-summary {
    display: none;
    color: var(--course-accent-secondary);
}

/* =====================================================
   PAGE LAYOUT
   ===================================================== */
.page-layout {
    display: flex;
    min-height: calc(100vh - 120px);
}

/* =====================================================
   COLLAPSIBLE SIDEBAR
   ===================================================== */
aside,
#sidebar-nav {
    width: var(--sidebar-collapsed);
    flex-shrink: 0;
    background: var(--course-bg-secondary);
    border-right: 1px solid var(--course-border);
    position: sticky;
    top: 0;
    height: 100vh;
    overflow: hidden;
    padding: 1rem 0;
    transition: width 0.25s ease;
    z-index: 100;
}

aside:hover,
#sidebar-nav:hover {
    width: var(--sidebar-expanded);
    overflow-y: auto;
}

/* Nav items hidden when collapsed */
aside .nav-topic,
aside .nav-subtopic,
aside .nav-section,
aside .nav-part,
#sidebar-nav .nav-topic,
#sidebar-nav .nav-subtopic,
#sidebar-nav .nav-section,
#sidebar-nav .nav-part {
    opacity: 0;
    transition: opacity 0.15s ease;
    white-space: nowrap;
}

aside:hover .nav-topic,
aside:hover .nav-subtopic,
aside:hover .nav-section,
aside:hover .nav-part,
#sidebar-nav:hover .nav-topic,
#sidebar-nav:hover .nav-subtopic,
#sidebar-nav:hover .nav-section,
#sidebar-nav:hover .nav-part {
    opacity: 1;
}

/* Collapsed expand indicator */
aside::before,
#sidebar-nav::before {
    content: "\25B6"; /* ▶ */
    display: block;
    text-align: center;
    color: var(--course-text-secondary);
    font-size: 1rem;
    padding: 1rem 0;
    transition: opacity 0.15s ease;
}

aside:hover::before,
#sidebar-nav:hover::before {
    opacity: 0;
    height: 0;
    padding: 0;
    overflow: hidden;
}

/* =====================================================
   NAVIGATION ITEMS
   ===================================================== */
.nav-part {
    margin-bottom: 1.5rem;
}

.nav-part-title {
    padding: 0.5rem 1rem;
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--course-text-muted);
}

.nav-topic {
    padding: 0.75rem 1rem;
    border-left: 3px solid transparent;
    transition: all 0.15s;
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    flex-wrap: wrap;
}

.nav-topic-title {
    font-weight: 600;
    font-size: 0.9rem;
    color: var(--course-text-primary);
    margin-bottom: 0.3rem;
    flex: 1;
}

.nav-topic.active .nav-topic-title {
    color: var(--course-accent);
}

.nav-keywords {
    display: flex;
    flex-wrap: wrap;
    gap: 0.3rem;
}

.nav-keyword {
    font-size: 0.65rem;
    color: var(--course-text-secondary);
    background: rgba(255, 255, 255, 0.05);
    padding: 0.15rem 0.4rem;
    border-radius: 3px;
}

.nav-subtopic {
    padding: 0.4rem 1rem 0.4rem 1.75rem;
    cursor: pointer;
    border-left: 2px solid transparent;
    transition: all 0.15s;
    font-size: 0.8rem;
    color: var(--course-text-secondary);
    display: flex;
    align-items: center;
}

.nav-subtopic:hover {
    background: rgba(255, 255, 255, 0.03);
    color: var(--course-text-primary);
}

.nav-subtopic.active {
    background: rgba(0, 255, 65, 0.03);
    border-left-color: var(--course-accent-secondary);
    color: var(--course-accent-secondary);
}

.nav-subtopic::before {
    content: "\2514"; /* └ */
    margin-right: 0.5rem;
    opacity: 0.4;
}

/* Simple nav section style */
.nav-section {
    display: block;
    padding: 0.6rem 1rem;
    color: var(--course-text-secondary);
    text-decoration: none;
    font-size: 0.85rem;
    border-left: 2px solid transparent;
    transition: all 0.15s;
    cursor: pointer;
}

.nav-section:hover {
    background: rgba(255, 255, 255, 0.03);
    color: var(--course-text-primary);
    text-decoration: none;
}

.nav-section.active {
    background: rgba(0, 255, 65, 0.03);
    color: var(--course-accent);
    border-left-color: var(--course-accent);
}

.nav-section.completed {
    color: var(--course-accent);
}

.nav-section.completed::before {
    content: "\2713 "; /* ✓ */
}

.nav-section.locked {
    color: var(--course-text-muted);
    cursor: not-allowed;
}

.nav-section .icon {
    margin-right: 0.5rem;
}

/* Mastery indicators */
.mastery-indicator {
    font-size: 0.7rem;
    font-weight: 600;
    padding: 0.1rem 0.4rem;
    border-radius: 4px;
    margin-left: 0.5rem;
    font-family: 'JetBrains Mono', monospace;
    white-space: nowrap;
}

.mastery-partial .mastery-indicator {
    background: rgba(251, 191, 36, 0.2);
    color: #fbbf24;
}

.mastery-almost .mastery-indicator {
    background: rgba(0, 212, 170, 0.2);
    color: var(--course-accent-secondary);
}

.mastery-complete .mastery-indicator {
    background: rgba(0, 255, 65, 0.2);
    color: var(--course-accent);
}

/* =====================================================
   MAIN CONTENT AREA
   ===================================================== */
main {
    flex: 1;
    max-width: 1400px;
    padding: 2rem 3rem;
    min-width: 0;
}

/* Content width constraints for readability */
main p,
main ul,
main ol,
main h3,
main .lesson-intro,
main .info-box,
main .warning-box,
main .story-box {
    max-width: var(--content-max-width);
}

main p {
    margin-bottom: 1.5rem;
}

main p:last-child {
    margin-bottom: 0;
}

main ul li,
main ol li {
    margin-bottom: 0.75rem;
}

main ul li:last-child,
main ol li:last-child {
    margin-bottom: 1.5rem;
}

/* =====================================================
   SECTIONS
   ===================================================== */
section {
    display: none;
    animation: fadeIn 0.3s ease;
}

section.active {
    display: block;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* =====================================================
   CARDS
   ===================================================== */
.card {
    background: var(--course-bg-card);
    border: 1px solid var(--course-border);
    padding: 2rem;
    margin-bottom: 1.5rem;
    border-radius: 0;
}

h2 {
    font-size: 1.6rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

h2 .icon {
    width: 34px;
    height: 34px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--course-accent);
    color: var(--course-bg-primary);
    font-size: 0.9rem;
    font-family: 'JetBrains Mono', monospace;
    border-radius: 0;
}

.lesson-intro {
    color: var(--course-text-secondary);
    font-size: 0.95rem;
    margin-bottom: 1.5rem;
    line-height: 1.7;
}

.lesson-intro p {
    margin-bottom: 1rem;
}

.lesson-intro p:last-child {
    margin-bottom: 0;
}

/* =====================================================
   CODE BLOCKS
   ===================================================== */
code {
    background: rgba(0, 255, 65, 0.08);
    border: 1px solid rgba(0, 255, 65, 0.2);
    padding: 0.1rem 0.35rem;
    border-radius: 4px;
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.85em;
    color: var(--course-accent);
}

pre {
    background: var(--course-bg-code);
    border: 1px solid var(--course-border);
    border-radius: 8px;
    padding: 16px;
    overflow-x: auto;
    margin: 16px 0;
}

pre code {
    background: none;
    border: none;
    padding: 0;
    margin: 0;
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.875rem;
    line-height: 1.5;
    color: var(--course-text-primary);
    display: block;
    white-space: pre;
}

/* =====================================================
   INFO & WARNING BOXES
   ===================================================== */
.info-box {
    background: linear-gradient(135deg, rgba(0, 212, 170, 0.08), transparent);
    border-left: 2px solid var(--course-accent-secondary);
    padding: 1rem 1.25rem;
    margin-top: 1.5rem;
    margin-bottom: 1.5rem;
    font-size: 0.9rem;
    color: var(--course-text-secondary);
    border-radius: 0;
}

.info-box strong {
    color: var(--course-accent-secondary);
}

.warning-box {
    background: linear-gradient(135deg, rgba(210, 153, 34, 0.08), transparent);
    border-left: 2px solid var(--course-accent-orange);
    padding: 1rem 1.25rem;
    margin-top: 1.5rem;
    margin-bottom: 1.5rem;
    font-size: 0.9rem;
    color: var(--course-text-secondary);
    border-radius: 0;
}

.warning-box strong {
    color: var(--course-accent-orange);
}

.story-box {
    background: linear-gradient(135deg, rgba(251, 191, 36, 0.08), transparent);
    border-left: 2px solid #fbbf24;
    padding: 1rem 1.25rem;
    margin-top: 1.5rem;
    margin-bottom: 1.5rem;
    font-size: 0.9rem;
    color: var(--course-text-secondary);
}

.story-box strong {
    color: #fbbf24;
}

/* =====================================================
   WIDGETS (base styles)
   ===================================================== */
.widget {
    background: var(--course-bg-code);
    border: 1px solid var(--course-border);
    border-radius: 8px;
    padding: 1.5rem;
    margin: 1.5rem 0;
}

.widget-title {
    font-size: 1rem;
    font-weight: 600;
    color: var(--course-accent-secondary);
    margin-bottom: 1rem;
    text-align: center;
}

/* =====================================================
   QUIZ SYSTEM
   ===================================================== */
.quiz {
    margin-top: 1.5rem;
    padding: 1.25rem;
    background: var(--course-bg-secondary);
    border: 1px solid var(--course-border);
    border-radius: 8px;
    max-width: var(--content-max-width);
}

.quiz-title {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--course-accent-secondary);
    margin-bottom: 1rem;
}

.quiz-question {
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--course-text-primary);
}

.quiz-options {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.quiz-option {
    display: flex;
    align-items: center;
    padding: 0.75rem 1rem;
    background: var(--course-bg-code);
    border: 1px solid var(--course-border);
    border-radius: 6px;
    cursor: pointer;
    transition: all 0.15s;
}

.quiz-option:hover {
    border-color: var(--course-accent-secondary);
}

.quiz-option.selected {
    border-color: var(--course-accent);
    background: rgba(0, 255, 65, 0.05);
}

.quiz-option.correct {
    border-color: #4ade80;
    background: rgba(74, 222, 128, 0.1);
}

.quiz-option.incorrect {
    border-color: #f87171;
    background: rgba(248, 113, 113, 0.1);
}

.quiz-option input {
    display: none;
}

.quiz-option .letter {
    width: 24px;
    height: 24px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--course-border);
    border-radius: 4px;
    margin-right: 0.75rem;
    font-size: 0.8rem;
    font-weight: 600;
    flex-shrink: 0;
}

.quiz-option.selected .letter {
    background: var(--course-accent);
    color: #000;
}

.quiz-option.correct .letter {
    background: #4ade80;
    color: #000;
}

.quiz-option.incorrect .letter {
    background: #f87171;
    color: #000;
}

.quiz-check,
.quiz-submit {
    margin-top: 1rem;
    padding: 0.6rem 1.5rem;
    background: var(--course-accent);
    color: #000;
    border: none;
    border-radius: 6px;
    font-weight: 600;
    cursor: pointer;
    transition: filter 0.15s;
}

.quiz-check:hover,
.quiz-submit:hover {
    filter: brightness(1.1);
}

.quiz-check:disabled,
.quiz-submit:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.quiz-feedback {
    margin-top: 1rem;
    padding: 0.75rem 1rem;
    border-radius: 6px;
    font-size: 0.9rem;
}

.quiz-feedback.correct {
    background: rgba(74, 222, 128, 0.1);
    border: 1px solid #4ade80;
    color: #4ade80;
}

.quiz-feedback.incorrect {
    background: rgba(248, 113, 113, 0.1);
    border: 1px solid #f87171;
    color: #f87171;
}

/* =====================================================
   EXPANDABLE SECTIONS
   ===================================================== */
.expand-section,
details.expand-section {
    margin-top: 1rem;
    border: 1px solid var(--course-border);
    border-radius: 6px;
    overflow: hidden;
}

.expand-section summary {
    padding: 0.75rem 1rem;
    background: var(--course-bg-secondary);
    cursor: pointer;
    font-weight: 500;
    color: var(--course-text-secondary);
    transition: all 0.15s;
    list-style: none;
}

.expand-section summary::-webkit-details-marker {
    display: none;
}

.expand-section summary::before {
    content: "\25B6"; /* ▶ */
    display: inline-block;
    margin-right: 0.5rem;
    transition: transform 0.15s;
    font-size: 0.75rem;
}

.expand-section[open] summary::before {
    transform: rotate(90deg);
}

.expand-section summary:hover {
    background: var(--course-bg-card);
    color: var(--course-text-primary);
}

.expand-content {
    padding: 1rem;
    background: var(--course-bg-card);
}

/* =====================================================
   ACHIEVEMENTS / CHALLENGES
   ===================================================== */
.achievements {
    margin-top: 1.5rem;
    padding: 1rem;
    background: rgba(0, 212, 170, 0.05);
    border-radius: 8px;
    border: 1px solid rgba(0, 212, 170, 0.2);
    max-width: var(--content-max-width);
}

.achievements-title {
    font-size: 1rem;
    font-weight: 600;
    color: var(--course-accent);
    margin-bottom: 1rem;
}

.achievement-list {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 0.75rem;
}

.achievement {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.75rem;
    background: var(--course-bg-secondary);
    border-radius: 6px;
    border: 1px solid var(--course-border);
    cursor: help;
    transition: all 0.2s;
}

.achievement.unlocked {
    border-color: var(--course-accent);
    background: rgba(0, 212, 170, 0.1);
}

.achievement-icon {
    font-size: 1.2rem;
    opacity: 0.5;
}

.achievement.unlocked .achievement-icon {
    opacity: 1;
}

.achievement-name {
    font-weight: 600;
    font-size: 0.85rem;
    color: var(--course-text-primary);
}

.achievement-desc {
    font-size: 0.75rem;
    color: var(--course-text-secondary);
    flex: 1;
}

/* =====================================================
   AUTH MODAL
   ===================================================== */
.auth-modal {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    z-index: 1000;
    display: flex;
    align-items: center;
    justify-content: center;
}

.auth-modal-backdrop {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.8);
}

.auth-modal-content {
    position: relative;
    background: var(--course-bg-secondary);
    border: 1px solid var(--course-border);
    border-radius: 12px;
    padding: 2rem;
    width: 90%;
    max-width: 400px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.5);
}

.auth-modal-close {
    position: absolute;
    top: 1rem;
    right: 1rem;
    background: none;
    border: none;
    color: var(--course-text-secondary);
    font-size: 1.5rem;
    cursor: pointer;
    line-height: 1;
    padding: 0;
}

.auth-modal-close:hover {
    color: var(--course-text-primary);
}

.auth-modal-content h2 {
    margin: 0 0 0.25rem 0;
    color: var(--course-accent);
    font-size: 1.5rem;
}

.auth-modal-subtitle {
    margin: 0 0 1.5rem 0;
    color: var(--course-text-secondary);
    font-size: 0.9rem;
}

.auth-modal-toggle {
    margin-top: 1.5rem;
    text-align: center;
    font-size: 0.85rem;
    color: var(--course-text-secondary);
}

.auth-modal-toggle button {
    background: none;
    border: none;
    color: var(--course-accent-secondary);
    cursor: pointer;
    text-decoration: underline;
    font-size: inherit;
}

/* Auth form overrides to match course theme */
.auth-form-group label {
    color: var(--course-accent-secondary);
}

.auth-form-group input[type="email"],
.auth-form-group input[type="password"],
.auth-form-group input[type="text"] {
    background: var(--course-bg-primary);
    border: 1px solid var(--course-border);
    color: var(--course-text-primary);
}

.auth-form-group input::placeholder {
    color: var(--course-text-secondary);
}

.auth-form-group input:focus {
    border-color: var(--course-accent-secondary);
    background: var(--course-bg-primary);
}

.auth-password-toggle {
    color: var(--course-text-secondary);
}

.auth-password-toggle:hover {
    color: var(--course-accent-secondary);
}

.auth-submit-btn {
    border: 1px solid var(--course-border);
    color: var(--course-accent);
    background: transparent;
}

.auth-submit-btn:hover {
    border-color: var(--course-accent);
    color: var(--course-accent);
}


/* =====================================================
   PAGE TIMING FOOTER
   ===================================================== */
#page-timing {
    position: fixed;
    bottom: 8px;
    right: 8px;
    font-size: 11px;
    color: var(--course-text-muted);
    font-family: 'JetBrains Mono', monospace;
}

/* =====================================================
   RESPONSIVE DESIGN
   ===================================================== */
@media (max-width: 900px) {
    .page-layout {
        flex-direction: column;
    }

    aside,
    #sidebar-nav {
        width: 100% !important;
        height: auto !important;
        position: relative;
        border-right: none;
        border-bottom: 1px solid var(--course-border);
        max-height: 50vh;
        overflow-y: auto !important;
    }

    aside::before,
    #sidebar-nav::before {
        display: none;
    }

    aside .nav-topic,
    aside .nav-subtopic,
    aside .nav-section,
    aside .nav-part,
    #sidebar-nav .nav-topic,
    #sidebar-nav .nav-subtopic,
    #sidebar-nav .nav-section,
    #sidebar-nav .nav-part {
        opacity: 1 !important;
    }

    main {
        padding: 1rem;
    }

    header {
        padding: 1rem;
        flex-wrap: wrap;
        gap: 0.5rem;
    }

    .header-brand h1 {
        font-size: 1.5rem;
    }

    .card {
        padding: 1.25rem;
    }

    .quiz {
        padding: 1rem;
    }

    .achievement-list {
        grid-template-columns: 1fr;
    }

    .achievement {
        flex-wrap: wrap;
        padding: 0.5rem;
        gap: 0.5rem;
    }

    .achievement-name {
        font-size: 0.8rem;
    }

    .achievement-desc {
        font-size: 0.7rem;
        width: 100%;
        margin-left: 1.75rem;
    }
}

@media (max-width: 600px) {
    header {
        flex-direction: column;
        align-items: flex-start;
    }

    .header-auth {
        width: 100%;
    }

    .progress-warning {
        width: 100%;
        align-items: center;
        text-align: center;
    }
}