/* ==========================================================================
   Plant Disease Detection Using Mobile Images and Video
   CS 663: Computer Vision - Project 1
   Student: Mahitha Rangineni (California State University, East Bay)
   Academic Tutorial Design System
   ========================================================================== */

:root {
    --primary-dark: #1b4332;
    --primary: #2d6a4f;
    --primary-medium: #40916c;
    --primary-light: #52b788;
    --accent-tint: #eaf5ee;
    --accent-border: #b7e4c7;
    
    --text-main: #1f2937;
    --text-muted: #4b5563;
    --text-light: #6b7280;
    
    --bg-page: #f4f7f5;
    --bg-card: #ffffff;
    --bg-code: #1e293b;
    --code-text: #f8fafc;
    
    --border-color: #e5e7eb;
    --border-dark: #cbd5e1;
    
    --warning-bg: #fffbeb;
    --warning-border: #fcd34d;
    --warning-text: #92400e;
    
    --info-bg: #eff6ff;
    --info-border: #93c5fd;
    --info-text: #1e40af;
    
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 14px;
    
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.06);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.1);
    
    --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    --font-mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-sans);
    margin: 0;
    background-color: var(--bg-page);
    color: var(--text-main);
    line-height: 1.7;
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
}

/* ==========================================================================
   Header & Academic Metadata
   ========================================================================== */

header {
    background: linear-gradient(135deg, var(--primary-dark) 0%, var(--primary) 100%);
    color: white;
    padding: 38px 24px;
    text-align: center;
    border-bottom: 4px solid var(--primary-light);
}

.header-badge {
    display: inline-block;
    background: rgba(255, 255, 255, 0.18);
    color: #e2f7ea;
    font-size: 0.85rem;
    font-weight: 600;
    letter-spacing: 0.05em;
    text-transform: uppercase;
    padding: 4px 14px;
    border-radius: 20px;
    margin-bottom: 12px;
    border: 1px solid rgba(255, 255, 255, 0.25);
}

header h1 {
    font-size: 2.1rem;
    margin: 0 0 10px 0;
    color: #ffffff;
    font-weight: 700;
    letter-spacing: -0.02em;
    line-height: 1.25;
}

.header-meta {
    font-size: 1.05rem;
    color: #d1fae5;
    margin: 6px 0 0 0;
    font-weight: 500;
}

.header-author {
    font-size: 0.95rem;
    color: #a7f3d0;
    margin-top: 6px;
}

/* ==========================================================================
   Navigation Bar
   ========================================================================== */

nav {
    background-color: var(--primary-dark);
    padding: 10px 16px;
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
}

.nav-container {
    max-width: 1100px;
    margin: 0 auto;
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    align-items: center;
    gap: 6px 8px;
}

nav a {
    color: #e5e7eb;
    text-decoration: none;
    padding: 6px 12px;
    font-size: 0.92rem;
    font-weight: 500;
    border-radius: var(--radius-sm);
    transition: all 0.2s ease;
    white-space: nowrap;
}

nav a:hover {
    color: #ffffff;
    background-color: rgba(255, 255, 255, 0.15);
    text-decoration: none;
}

nav a.active {
    color: #ffffff;
    background-color: var(--primary-light);
    color: #064e3b;
    font-weight: 700;
}

/* ==========================================================================
   Main Content Layout
   ========================================================================== */

main {
    max-width: 980px;
    margin: 36px auto;
    background: var(--bg-card);
    padding: 42px 48px;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    border: 1px solid var(--border-color);
}

section {
    margin-bottom: 44px;
}

section:last-of-type {
    margin-bottom: 24px;
}

/* ==========================================================================
   Typography & Academic Elements
   ========================================================================== */

h1, h2, h3, h4 {
    color: var(--primary-dark);
    font-weight: 700;
    line-height: 1.3;
}

h2 {
    font-size: 1.65rem;
    margin-top: 0;
    margin-bottom: 18px;
    padding-bottom: 8px;
    border-bottom: 2px solid var(--accent-border);
    position: relative;
}

h2::before {
    content: "";
    position: absolute;
    bottom: -2px;
    left: 0;
    width: 60px;
    height: 2px;
    background-color: var(--primary);
}

h3 {
    font-size: 1.25rem;
    margin-top: 26px;
    margin-bottom: 12px;
    color: var(--primary);
}

h4 {
    font-size: 1.05rem;
    margin-top: 20px;
    margin-bottom: 8px;
    color: var(--text-main);
}

p {
    margin: 0 0 16px 0;
    color: var(--text-main);
}

ul, ol {
    margin: 0 0 20px 0;
    padding-left: 24px;
}

li {
    margin-bottom: 8px;
    color: var(--text-main);
}

strong {
    color: #111827;
}

a {
    color: var(--primary);
    text-decoration: underline;
    text-underline-offset: 3px;
    transition: color 0.15s ease;
}

a:hover {
    color: var(--primary-dark);
}

/* Citations styling */
a[href*="references.html"] {
    font-weight: 600;
    color: var(--primary);
    background-color: var(--accent-tint);
    padding: 1px 5px;
    border-radius: 4px;
    text-decoration: none;
    border: 1px solid var(--accent-border);
    font-size: 0.88rem;
    white-space: nowrap;
}

a[href*="references.html"]:hover {
    background-color: var(--primary-light);
    color: #064e3b;
    border-color: var(--primary-light);
}

hr {
    border: none;
    border-top: 1px solid var(--border-color);
    margin: 32px 0;
}

/* ==========================================================================
   Cards & Roadmap Grids (Home Page & Overview)
   ========================================================================== */

.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 20px;
    margin: 24px 0 32px 0;
}

.tutorial-card {
    background: #ffffff;
    border: 1px solid var(--border-color);
    border-top: 4px solid var(--primary);
    border-radius: var(--radius-md);
    padding: 22px;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
}

.tutorial-card:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-md);
    border-color: var(--accent-border);
}

.tutorial-card .card-step {
    font-size: 0.78rem;
    font-weight: 700;
    color: var(--primary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 6px;
}

.tutorial-card h3 {
    margin: 0 0 10px 0;
    font-size: 1.15rem;
    color: var(--primary-dark);
}

.tutorial-card p {
    font-size: 0.94rem;
    color: var(--text-muted);
    margin-bottom: 16px;
    flex-grow: 1;
}

.tutorial-card .card-link {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--primary);
    display: inline-flex;
    align-items: center;
    gap: 4px;
    text-decoration: none;
}

.tutorial-card .card-link:hover {
    color: var(--primary-dark);
    text-decoration: underline;
}

/* Roadmap Flow */
.roadmap-container {
    background-color: var(--accent-tint);
    border: 1px solid var(--accent-border);
    border-radius: var(--radius-md);
    padding: 24px;
    margin: 24px 0;
}

.roadmap-steps {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.roadmap-step-item {
    display: flex;
    align-items: flex-start;
    gap: 14px;
}

.roadmap-badge {
    background: var(--primary);
    color: white;
    font-weight: 700;
    font-size: 0.85rem;
    width: 28px;
    height: 28px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
    margin-top: 2px;
}

.roadmap-content h4 {
    margin: 0 0 4px 0;
    font-size: 1rem;
    color: var(--primary-dark);
}

.roadmap-content p {
    margin: 0;
    font-size: 0.92rem;
    color: var(--text-muted);
}

/* ==========================================================================
   Callouts & Information Boxes
   ========================================================================== */

.callout {
    background-color: var(--accent-tint);
    border-left: 4px solid var(--primary);
    border-radius: var(--radius-sm);
    padding: 18px 22px;
    margin: 22px 0;
}

.callout h4 {
    margin-top: 0;
    color: var(--primary-dark);
    font-size: 1.05rem;
}

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

.callout-warning {
    background-color: var(--warning-bg);
    border-left: 4px solid #f59e0b;
    border-radius: var(--radius-sm);
    padding: 18px 22px;
    margin: 22px 0;
}

.callout-warning h4 {
    margin-top: 0;
    color: var(--warning-text);
    font-size: 1.05rem;
}

.callout-info {
    background-color: var(--info-bg);
    border-left: 4px solid #3b82f6;
    border-radius: var(--radius-sm);
    padding: 18px 22px;
    margin: 22px 0;
}

/* ==========================================================================
   Figures, Images & Media Captions
   ========================================================================== */

figure.figure-container {
    margin: 28px auto;
    text-align: center;
    background: #fafbfa;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 16px;
    box-shadow: var(--shadow-sm);
}

figure.figure-container img {
    width: 100%;
    max-width: 860px;
    height: auto;
    display: block;
    margin: 0 auto;
    border-radius: var(--radius-sm);
    border: 1px solid #e5e7eb;
}

figcaption {
    margin-top: 14px;
    font-size: 0.92rem;
    color: var(--text-muted);
    line-height: 1.5;
    padding: 0 10px;
}

figcaption .figure-title {
    font-weight: 700;
    color: var(--primary-dark);
    display: block;
    margin-bottom: 4px;
}

.author-credit {
    display: inline-block;
    font-size: 0.8rem;
    color: var(--text-light);
    margin-top: 6px;
    background: #f1f5f2;
    padding: 3px 10px;
    border-radius: 12px;
    border: 1px solid #e0e7e1;
}

/* ==========================================================================
   Tables & Data Summaries
   ========================================================================== */

.table-wrapper {
    overflow-x: auto;
    margin: 24px 0 28px 0;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
}

table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.96rem;
    text-align: left;
    background: white;
}

thead {
    background-color: var(--primary);
    color: white;
}

th {
    padding: 14px 18px;
    font-weight: 600;
    letter-spacing: 0.02em;
    border-bottom: 2px solid var(--primary-dark);
}

td {
    padding: 12px 18px;
    border-bottom: 1px solid var(--border-color);
    color: var(--text-main);
}

tbody tr:nth-child(even) {
    background-color: #f9fbf9;
}

tbody tr:hover {
    background-color: #f0f7f2;
}

/* ==========================================================================
   Code Blocks & Algorithm Displays
   ========================================================================== */

.code-wrapper {
    background: var(--bg-code);
    border-radius: var(--radius-md);
    margin: 24px 0;
    overflow: hidden;
    box-shadow: var(--shadow-md);
    border: 1px solid #334155;
}

.code-header {
    background: #0f172a;
    padding: 10px 18px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: 1px solid #334155;
}

.code-lang {
    color: #94a3b8;
    font-size: 0.82rem;
    font-weight: 600;
    letter-spacing: 0.05em;
    text-transform: uppercase;
}

.code-title {
    color: #e2e8f0;
    font-size: 0.88rem;
    font-weight: 500;
}

pre {
    margin: 0;
    padding: 20px 22px;
    overflow-x: auto;
    background: var(--bg-code);
    border-left: none;
    border-radius: 0;
}

pre code {
    font-family: var(--font-mono);
    font-size: 0.92rem;
    line-height: 1.6;
    color: var(--code-text);
    background: transparent;
    padding: 0;
    border: none;
}

/* Inline Code */
code {
    font-family: var(--font-mono);
    font-size: 0.88em;
    background-color: #eef2f0;
    color: #065f46;
    padding: 2px 6px;
    border-radius: 4px;
    border: 1px solid #d1fae5;
}

.code-annotation-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
    margin: 16px 0 24px 0;
}

.annotation-card {
    background: #f8faf8;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    padding: 14px 18px;
}

.annotation-card h4 {
    margin: 0 0 6px 0;
    font-size: 0.92rem;
    color: var(--primary);
    text-transform: uppercase;
    letter-spacing: 0.04em;
}

.annotation-card p {
    margin: 0;
    font-size: 0.92rem;
    color: var(--text-muted);
}

/* ==========================================================================
   Audio Support Section (Condition-Safe)
   ========================================================================== */

.audio-section {
    background: linear-gradient(135deg, #f0fdf4 0%, #e6f4ea 100%);
    border: 1px solid var(--accent-border);
    border-radius: var(--radius-md);
    padding: 22px 26px;
    margin: 36px 0;
}

.audio-section-header {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 12px;
}

.audio-badge {
    background: var(--primary);
    color: white;
    font-size: 0.75rem;
    font-weight: 700;
    padding: 2px 8px;
    border-radius: 12px;
    text-transform: uppercase;
}

.audio-section h3 {
    margin: 0;
    font-size: 1.15rem;
    color: var(--primary-dark);
}

.audio-description {
    font-size: 0.92rem;
    color: var(--text-muted);
    margin-bottom: 14px;
}

.audio-player-container {
    margin-top: 10px;
}

audio.page-audio {
    width: 100%;
    max-width: 550px;
    display: block;
    height: 42px;
    outline: none;
}

.audio-placeholder {
    display: flex;
    align-items: center;
    gap: 14px;
    background: #ffffff;
    border: 1px dashed var(--accent-border);
    padding: 14px 18px;
    border-radius: var(--radius-sm);
    color: var(--text-muted);
    font-size: 0.9rem;
}

.audio-placeholder-icon {
    font-size: 1.6rem;
    color: var(--primary);
    flex-shrink: 0;
}

.audio-placeholder strong {
    color: var(--primary-dark);
    display: block;
    margin-bottom: 2px;
}

/* ==========================================================================
   Interactive Quiz Component
   ========================================================================== */

#quiz {
    background: #ffffff;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 28px 32px;
    box-shadow: var(--shadow-sm);
}

.quiz-question-card {
    background: #fbfcfb;
    border: 1px solid #eef2ef;
    border-radius: var(--radius-md);
    padding: 18px 22px;
    margin-bottom: 20px;
    transition: border-color 0.2s;
}

.quiz-question-card:hover {
    border-color: var(--accent-border);
}

.quiz-question-title {
    font-size: 1.02rem;
    font-weight: 600;
    color: var(--primary-dark);
    margin: 0 0 12px 0;
}

.quiz-options {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.quiz-option-label {
    display: flex;
    align-items: flex-start;
    gap: 10px;
    padding: 9px 14px;
    border-radius: var(--radius-sm);
    background: white;
    border: 1px solid var(--border-color);
    cursor: pointer;
    font-size: 0.95rem;
    transition: all 0.15s ease;
}

.quiz-option-label:hover {
    background: var(--accent-tint);
    border-color: var(--accent-border);
}

.quiz-option-label input[type="radio"] {
    margin-top: 4px;
    accent-color: var(--primary);
    cursor: pointer;
}

.quiz-controls {
    display: flex;
    align-items: center;
    gap: 14px;
    margin-top: 24px;
    flex-wrap: wrap;
}

#quiz button, .quiz-btn {
    background-color: var(--primary);
    color: white;
    border: none;
    padding: 12px 24px;
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-weight: 600;
    font-size: 0.98rem;
    transition: background-color 0.2s ease, transform 0.1s ease;
    box-shadow: var(--shadow-sm);
}

#quiz button:hover, .quiz-btn:hover {
    background-color: var(--primary-dark);
}

#quiz button:active, .quiz-btn:active {
    transform: translateY(1px);
}

.quiz-btn-reset {
    background-color: #64748b !important;
}

.quiz-btn-reset:hover {
    background-color: #475569 !important;
}

#quizResult {
    margin-top: 20px;
    padding: 16px 20px;
    border-radius: var(--radius-sm);
    font-size: 1.05rem;
    display: none;
}

#quizResult.show {
    display: block;
}

#quizResult.quiz-success {
    background-color: #ecfdf5;
    border: 1px solid #a7f3d0;
    color: #065f46;
}

#quizResult.quiz-retry {
    background-color: #fef2f2;
    border: 1px solid #fecaca;
    color: #991b1b;
}

/* ==========================================================================
   Interview & Research Labs Formatting
   ========================================================================== */

.interview-box {
    background: #ffffff;
    border: 1px solid var(--border-color);
    border-left: 4px solid var(--primary);
    border-radius: var(--radius-md);
    padding: 24px;
    margin: 22px 0;
}

.interview-status-tag {
    display: inline-block;
    background: #fef3c7;
    color: #92400e;
    font-size: 0.8rem;
    font-weight: 700;
    padding: 4px 12px;
    border-radius: 12px;
    margin-bottom: 12px;
    border: 1px solid #fde68a;
    text-transform: uppercase;
    letter-spacing: 0.04em;
}

.interview-question-list {
    margin: 16px 0;
    padding-left: 20px;
}

.interview-question-list li {
    margin-bottom: 14px;
    color: #1f2937;
}

.interview-question-list strong {
    color: var(--primary-dark);
}

.lab-card {
    background: #fbfdfc;
    border: 1px solid var(--accent-border);
    border-radius: var(--radius-md);
    padding: 20px 24px;
    margin: 18px 0;
}

.lab-card h4 {
    margin-top: 0;
    color: var(--primary-dark);
    font-size: 1.1rem;
}

.lab-card .lab-location {
    font-size: 0.88rem;
    color: var(--text-light);
    margin-bottom: 10px;
    font-weight: 500;
}

/* ==========================================================================
   References & Bibliography
   ========================================================================== */

.reference-entry {
    background: #ffffff;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 22px 26px;
    margin-bottom: 24px;
    transition: box-shadow 0.2s ease, border-color 0.2s ease;
}

.reference-entry:target {
    border-color: var(--primary-light);
    box-shadow: 0 0 0 3px rgba(82, 183, 136, 0.35);
    background-color: #fafdfb;
}

.reference-entry h3 {
    margin-top: 0;
    margin-bottom: 10px;
    font-size: 1.18rem;
    color: var(--primary-dark);
}

.reference-citation {
    font-size: 0.98rem;
    line-height: 1.6;
    margin-bottom: 12px;
    color: #1f2937;
}

.reference-meta {
    background: #f8faf8;
    border-radius: var(--radius-sm);
    padding: 12px 16px;
    margin: 12px 0;
    font-size: 0.92rem;
}

.reference-link-btn {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    background-color: var(--accent-tint);
    color: var(--primary-dark);
    font-weight: 600;
    font-size: 0.88rem;
    padding: 6px 14px;
    border-radius: var(--radius-sm);
    text-decoration: none;
    border: 1px solid var(--accent-border);
    margin-top: 8px;
    transition: all 0.15s ease;
}

.reference-link-btn:hover {
    background-color: var(--primary);
    color: white;
    text-decoration: none;
}

/* ==========================================================================
   Tutorial Navigation Pagination (Previous / Next Buttons)
   ========================================================================== */

.tutorial-nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 16px;
    margin-top: 48px;
    padding-top: 28px;
    border-top: 1px solid var(--border-color);
}

.tutorial-nav-btn {
    display: inline-flex;
    flex-direction: column;
    text-decoration: none;
    padding: 10px 18px;
    border-radius: var(--radius-md);
    border: 1px solid var(--border-color);
    background: #ffffff;
    transition: all 0.2s ease;
    max-width: 48%;
}

.tutorial-nav-btn:hover {
    border-color: var(--primary-light);
    background-color: var(--accent-tint);
    text-decoration: none;
    transform: translateY(-2px);
    box-shadow: var(--shadow-sm);
}

.tutorial-nav-btn.prev {
    text-align: left;
}

.tutorial-nav-btn.next {
    text-align: right;
    margin-left: auto;
    background-color: #f7fbf8;
    border-color: var(--accent-border);
}

.tutorial-nav-label {
    font-size: 0.78rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-light);
    margin-bottom: 2px;
}

.tutorial-nav-title {
    font-size: 0.95rem;
    font-weight: 600;
    color: var(--primary);
}

/* ==========================================================================
   Footer
   ========================================================================== */

footer {
    text-align: center;
    padding: 36px 20px;
    background-color: #e5ece6;
    color: var(--text-muted);
    font-size: 0.92rem;
    border-top: 1px solid #d4ded6;
}

footer p {
    margin: 4px 0;
    color: var(--text-muted);
}

.footer-academic {
    font-weight: 600;
    color: var(--primary-dark);
}

/* ==========================================================================
   Responsive Breakpoints
   ========================================================================== */

@media (max-width: 768px) {
    header {
        padding: 28px 16px;
    }

    header h1 {
        font-size: 1.65rem;
    }

    main {
        margin: 18px 12px;
        padding: 26px 20px;
        border-radius: var(--radius-md);
    }

    h2 {
        font-size: 1.4rem;
    }

    nav {
        padding: 8px 10px;
    }

    .nav-container {
        gap: 4px 6px;
    }

    nav a {
        padding: 5px 9px;
        font-size: 0.85rem;
    }

    .code-annotation-grid {
        grid-template-columns: 1fr;
    }

    .tutorial-nav {
        flex-direction: column;
        align-items: stretch;
    }

    .tutorial-nav-btn {
        max-width: 100%;
        text-align: center !important;
    }
}