/* ConSynth-X Human Validation Platform
   Design system matched to main ConSynth-X website */

/* ===== CSS Variables (from main website) ===== */
:root {
    --bg-primary: #FFFFFF;
    --bg-secondary: #F8FAFC;
    --bg-card: #FFFFFF;
    --bg-card-hover: #F1F5F9;
    --border: #E2E8F0;
    --border-accent: #CBD5E1;
    --text-primary: #0F172A;
    --text-secondary: #475569;
    --text-muted: #94A3B8;
    --accent-orange: #C2410C;
    --accent-amber: #B45309;
    --accent-blue: #1D4ED8;
    --accent-cyan: #0E7490;
    --accent-red: #B91C1C;
    --accent-purple: #6D28D9;
    --grid-line: rgba(15, 23, 42, 0.05);
    --grid-color: rgba(15, 23, 42, 0.025);
    --card-shadow: 0 1px 2px rgba(15, 23, 42, 0.04), 0 1px 3px rgba(15, 23, 42, 0.06);
    --card-shadow-hover: 0 4px 12px rgba(15, 23, 42, 0.08), 0 2px 6px rgba(15, 23, 42, 0.05);
    --font-display: 'Crimson Pro', 'Source Serif 4', Georgia, serif;
    --font-mono: 'IBM Plex Mono', 'SF Mono', Menlo, monospace;
    --font-body: 'Source Sans 3', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --radius: 4px;
    --radius-lg: 8px;
}

/* ===== Reset & Base ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html {
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
}

body {
    font-family: var(--font-body);
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.65;
    overflow-x: hidden;
    font-size: 16px;
}

/* ===== Blueprint Grid Background ===== */
body::before {
    display: none;
}

/* ===== Navbar ===== */
.navbar {
    position: sticky;
    top: 0;
    z-index: 100;
    padding: 1rem 2rem;
    backdrop-filter: blur(20px);
    background: rgba(255, 255, 255, 0.88);
    border-bottom: 1px solid var(--border);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.navbar-brand {
    font-family: var(--font-display);
    font-weight: 800;
    font-size: 1.15rem;
    color: var(--text-primary);
    text-decoration: none;
    letter-spacing: -0.02em;
}

.navbar-brand .highlight {
    color: var(--accent-orange);
}

.navbar-links {
    display: flex;
    gap: 1.5rem;
    align-items: center;
}

.navbar-links a {
    font-family: var(--font-mono);
    font-size: 0.8rem;
    color: var(--text-secondary);
    text-decoration: none;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    transition: color 0.2s;
    position: relative;
}

.navbar-links a::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 1px;
    background: var(--accent-orange);
    transition: width 0.3s ease;
}

.navbar-links a:hover { color: var(--text-primary); }
.navbar-links a:hover::after { width: 100%; }
.navbar-links a.active {
    color: var(--accent-orange);
}
.navbar-links a.active::after { width: 100%; }

/* ===== Layout ===== */
.container {
    position: relative;
    z-index: 2;
    max-width: 900px;
    margin: 0 auto;
    padding: 3rem 2rem;
}

.container-wide {
    position: relative;
    z-index: 2;
    max-width: 1200px;
    margin: 0 auto;
    padding: 3rem 2rem;
}

/* ===== Cards ===== */
.card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 2rem;
    margin-bottom: 1.5rem;
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
    box-shadow: var(--card-shadow);
}

.card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 2px;
    background: linear-gradient(90deg, transparent, var(--accent-orange), transparent);
    opacity: 0;
    transition: opacity 0.3s;
}

.card:hover {
    border-color: var(--border-accent);
    background: var(--bg-card-hover);
    box-shadow: var(--card-shadow-hover);
}

.card:hover::before { opacity: 1; }

.card-title {
    font-family: var(--font-display);
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 1rem;
    letter-spacing: -0.01em;
}

/* ===== Login ===== */
.login-wrapper {
    position: relative;
    z-index: 2;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    padding: 2rem;
}

.login-card {
    width: 100%;
    max-width: 620px;
}

.login-consent {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 1.15rem;
    margin-bottom: 1.25rem;
}

.login-consent h2 {
    font-family: var(--font-display);
    font-size: 1.2rem;
    font-weight: 700;
    letter-spacing: 0;
    margin-bottom: 0.4rem;
}

.login-consent p {
    color: var(--text-secondary);
    font-size: 0.92rem;
    line-height: 1.55;
}

.login-study-meta {
    display: grid;
    gap: 0.6rem;
    margin: 1rem 0;
}

.login-study-meta div {
    display: grid;
    grid-template-columns: 150px 1fr;
    gap: 0.75rem;
    padding-top: 0.6rem;
    border-top: 1px solid var(--border);
}

.login-study-meta dt {
    font-family: var(--font-mono);
    font-size: 0.68rem;
    font-weight: 600;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: var(--text-muted);
}

.login-study-meta dd {
    color: var(--text-primary);
    font-size: 0.9rem;
    line-height: 1.4;
}

.login-study-meta a {
    color: var(--accent-blue);
}

.consent-list {
    display: grid;
    gap: 0.45rem;
    list-style: none;
    margin-top: 0.9rem;
}

.consent-list li {
    position: relative;
    padding-left: 1.35rem;
    color: var(--text-secondary);
    font-size: 0.9rem;
    line-height: 1.45;
}

.consent-list li::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0.48rem;
    width: 0.48rem;
    height: 0.48rem;
    border-radius: 50%;
    background: var(--accent-cyan);
    box-shadow: 0 0 0 4px rgba(0, 212, 170, 0.12);
}

.login-guide {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-left: 3px solid var(--accent-orange);
    border-radius: var(--radius);
    padding: 1rem 1.1rem 0.9rem;
    margin-bottom: 1.5rem;
}

.login-guide h3 {
    font-family: var(--font-mono);
    font-size: 0.72rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.12em;
    color: var(--accent-orange);
    margin-bottom: 0.7rem;
}

.login-guide ol {
    padding-left: 1.1rem;
    margin: 0 0 0.8rem;
    color: var(--text-secondary);
    font-size: 0.88rem;
    line-height: 1.55;
}

.login-guide ol li { margin-bottom: 0.35rem; }
.login-guide ol li strong { color: var(--text-primary); }

.login-guide kbd {
    display: inline-block;
    padding: 0.05rem 0.35rem;
    font-family: var(--font-mono);
    font-size: 0.72rem;
    background: var(--bg-card);
    border: 1px solid var(--border-accent);
    border-radius: 3px;
    color: var(--text-primary);
}

.login-guide-meta {
    font-size: 0.75rem;
    color: var(--text-muted);
    line-height: 1.5;
    margin: 0;
    padding-top: 0.5rem;
    border-top: 1px dashed var(--border);
}

.check-row {
    display: flex !important;
    align-items: flex-start;
    gap: 0.65rem;
    padding: 0.8rem 0.9rem;
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    color: var(--text-secondary) !important;
    font-family: var(--font-body) !important;
    font-size: 0.92rem !important;
    line-height: 1.45;
    text-transform: none !important;
    letter-spacing: 0 !important;
    cursor: pointer;
}

.check-row input {
    width: auto !important;
    margin-top: 0.2rem;
    accent-color: var(--accent-orange);
    flex-shrink: 0;
}

.username-row {
    display: flex;
    gap: 0.6rem;
    align-items: stretch;
}

.username-row input {
    min-width: 0;
}

.username-random {
    flex-shrink: 0;
    padding-inline: 1rem;
}

.login-card h1 {
    font-family: var(--font-display);
    font-size: 2rem;
    font-weight: 800;
    margin-bottom: 0.5rem;
    letter-spacing: -0.02em;
}

.login-card h1 .highlight {
    background: linear-gradient(135deg, var(--accent-orange), var(--accent-amber));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.login-card p.subtitle {
    font-family: var(--font-mono);
    color: var(--text-muted);
    margin-bottom: 2rem;
    font-size: 0.8rem;
    text-transform: uppercase;
    letter-spacing: 0.08em;
}

/* ===== Forms ===== */
.form-group { margin-bottom: 1.25rem; }

.form-group label {
    display: block;
    font-family: var(--font-mono);
    font-weight: 500;
    margin-bottom: 0.4rem;
    font-size: 0.8rem;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.06em;
}

.form-group input {
    width: 100%;
    padding: 0.75rem 1rem;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    font-size: 1rem;
    font-family: var(--font-body);
    background: var(--bg-secondary);
    color: var(--text-primary);
    transition: border 0.2s;
}

.form-group input::placeholder { color: var(--text-muted); }

.form-group input:focus {
    outline: none;
    border-color: var(--accent-orange);
    box-shadow: 0 0 0 3px rgba(255, 107, 53, 0.15);
}

/* ===== Buttons ===== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: var(--radius);
    font-family: var(--font-mono);
    font-size: 0.85rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.25s ease;
    text-decoration: none;
    letter-spacing: 0.02em;
}

.btn-primary {
    background: var(--accent-orange);
    color: #fff;
}

.btn-primary:hover {
    background: #9A3412;
    transform: translateY(-2px);
    box-shadow: 0 8px 24px rgba(194, 65, 12, 0.18);
}

.btn-success { background: var(--accent-cyan); color: var(--bg-primary); }
.btn-danger { background: var(--accent-red); color: #fff; }

.btn-outline {
    background: transparent;
    border: 1px solid var(--border-accent);
    color: var(--text-secondary);
}

.btn-outline:hover {
    color: var(--text-primary);
    border-color: var(--text-secondary);
    transform: translateY(-2px);
}

.btn-lg { padding: 0.9rem 2.25rem; font-size: 0.9rem; }
.btn-block { width: 100%; }
.btn:disabled { opacity: 0.4; cursor: not-allowed; transform: none !important; }

/* ===== Task image display ===== */
.task-image-container {
    display: flex;
    justify-content: center;
    align-items: center;
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    overflow: hidden;
    margin-bottom: 2rem;
    min-height: 400px;
    max-height: 600px;
}

.task-image-container img {
    max-width: 100%;
    max-height: 600px;
    object-fit: contain;
}

/* ===== Response buttons (Turing) ===== */
.response-buttons {
    display: flex;
    gap: 1rem;
    justify-content: center;
    margin: 2rem 0;
}

.response-btn {
    flex: 1;
    max-width: 260px;
    padding: 1.25rem 2rem;
    font-family: var(--font-display);
    font-size: 1.1rem;
    font-weight: 600;
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    background: var(--bg-card);
    color: var(--text-primary);
    cursor: pointer;
    transition: all 0.25s ease;
}

.response-btn:hover {
    border-color: var(--accent-orange);
    background: var(--bg-card-hover);
    transform: translateY(-2px);
    box-shadow: var(--card-shadow-hover);
}

.response-btn.selected {
    border-color: var(--accent-orange);
    background: rgba(194, 65, 12, 0.08);
}

.response-btn .key-hint {
    display: block;
    font-family: var(--font-mono);
    font-size: 0.7rem;
    color: var(--text-muted);
    margin-top: 0.4rem;
    font-weight: 400;
    letter-spacing: 0.04em;
}

/* ===== Likert scale (MOS) ===== */
.likert-scale {
    display: flex;
    justify-content: center;
    gap: 1rem;
    margin: 2rem 0;
}

.likert-option {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.4rem;
    cursor: pointer;
}

.likert-option input[type="radio"] { display: none; }

.likert-circle {
    width: 56px;
    height: 56px;
    border-radius: 50%;
    border: 1px solid var(--border);
    display: flex;
    align-items: center;
    justify-content: center;
    font-family: var(--font-display);
    font-size: 1.3rem;
    font-weight: 700;
    transition: all 0.25s ease;
    background: var(--bg-card);
    color: var(--text-primary);
}

.likert-option:hover .likert-circle {
    border-color: var(--accent-orange);
    background: var(--bg-card-hover);
    transform: translateY(-2px);
}

.likert-option input:checked + .likert-circle {
    border-color: var(--accent-orange);
    background: var(--accent-orange);
    color: #fff;
    box-shadow: 0 4px 16px rgba(194, 65, 12, 0.18);
}

.likert-label {
    font-family: var(--font-mono);
    font-size: 0.65rem;
    color: var(--text-muted);
    text-align: center;
    max-width: 80px;
    text-transform: uppercase;
    letter-spacing: 0.04em;
}

/* ===== Condition grid (Recognition) ===== */
.condition-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 0.75rem;
    margin: 2rem 0;
}

.condition-option {
    padding: 1rem;
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    text-align: center;
    cursor: pointer;
    font-family: var(--font-body);
    font-weight: 500;
    color: var(--text-secondary);
    background: var(--bg-card);
    transition: all 0.25s ease;
}

.condition-option:hover {
    border-color: var(--accent-orange);
    color: var(--text-primary);
    background: var(--bg-card-hover);
    transform: translateY(-2px);
}

.condition-option.selected {
    border-color: var(--accent-orange);
    background: rgba(194, 65, 12, 0.08);
    color: var(--text-primary);
}

.condition-option .key-hint {
    display: block;
    font-family: var(--font-mono);
    font-size: 0.65rem;
    color: var(--text-muted);
    margin-top: 0.3rem;
}

/* ===== Progress bar ===== */
.progress-bar-container {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    margin-bottom: 1.5rem;
}

.progress-bar {
    flex: 1;
    height: 4px;
    background: var(--border);
    border-radius: 2px;
    overflow: hidden;
}

.progress-bar-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--accent-orange), var(--accent-amber));
    border-radius: 2px;
    transition: width 0.3s;
}

.progress-text {
    font-family: var(--font-mono);
    font-size: 0.8rem;
    color: var(--text-muted);
    white-space: nowrap;
    letter-spacing: 0.04em;
}

/* ===== Home page task cards ===== */
.study-eyebrow {
    font-family: var(--font-mono);
    font-size: 0.75rem;
    font-weight: 600;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    color: var(--accent-orange);
    margin-bottom: 0.85rem;
}

.task-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.25rem;
}

.task-card {
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 2rem;
    background: var(--bg-card);
    text-decoration: none;
    color: var(--text-primary);
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
    box-shadow: var(--card-shadow);
}

.task-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 2px;
    background: linear-gradient(90deg, transparent, var(--accent-orange), transparent);
    opacity: 0;
    transition: opacity 0.3s;
}

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

.task-card:hover::before { opacity: 1; }

.task-card h3 {
    font-family: var(--font-display);
    font-weight: 600;
    margin-bottom: 0.5rem;
    letter-spacing: -0.01em;
}

.task-card p {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin-bottom: 1.25rem;
    line-height: 1.5;
}

.task-card .task-progress {
    font-family: var(--font-mono);
    font-size: 0.8rem;
    color: var(--accent-orange);
    font-weight: 500;
    letter-spacing: 0.04em;
}

/* ===== Dashboard ===== */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: 1rem;
    margin-bottom: 2rem;
}

.stat-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
    text-align: center;
    box-shadow: var(--card-shadow);
}

.stat-value {
    font-family: var(--font-display);
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--text-primary);
    letter-spacing: -0.02em;
}

.stat-label {
    font-family: var(--font-mono);
    font-size: 0.7rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.1em;
    margin-top: 0.25rem;
}

table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.9rem;
}

th, td {
    padding: 0.75rem 1rem;
    text-align: left;
    border-bottom: 1px solid var(--border);
}

th {
    font-family: var(--font-mono);
    font-weight: 500;
    font-size: 0.75rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.08em;
    background: var(--bg-secondary);
}

td { color: var(--text-secondary); }

/* ===== Tutorial ===== */
.tutorial-step {
    display: flex;
    gap: 1.5rem;
    align-items: flex-start;
    margin-bottom: 2.5rem;
    padding-bottom: 2.5rem;
    border-bottom: 1px solid var(--border);
}

.tutorial-step:last-child { border-bottom: none; }

.tutorial-step-num {
    flex-shrink: 0;
    width: 44px;
    height: 44px;
    background: var(--accent-orange);
    color: #fff;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-family: var(--font-display);
    font-weight: 700;
    font-size: 1.1rem;
}

.tutorial-step-content h3 {
    font-family: var(--font-display);
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.tutorial-step-content p {
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.7;
}

/* ===== Flash messages ===== */
.flash {
    padding: 0.8rem 1rem;
    border-radius: var(--radius);
    margin-bottom: 1rem;
    font-size: 0.9rem;
}

.flash-error {
    background: rgba(255, 71, 87, 0.1);
    color: var(--accent-red);
    border: 1px solid rgba(255, 71, 87, 0.25);
}

.flash-success {
    background: rgba(0, 212, 170, 0.1);
    color: var(--accent-cyan);
    border: 1px solid rgba(0, 212, 170, 0.25);
}

/* ===== Task complete ===== */
/* ===== Realism intro panel (shown before test starts) ===== */
.intro-panel {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 2.5rem 2rem;
    max-width: 780px;
    margin: 0 auto;
}

.intro-title {
    font-family: var(--font-display);
    font-weight: 700;
    letter-spacing: -0.02em;
    margin-bottom: 0.5rem;
}

.intro-sub {
    color: var(--text-muted);
    margin-bottom: 2rem;
}

.intro-section {
    margin-bottom: 1.75rem;
}

.intro-section h3 {
    font-family: var(--font-mono);
    font-size: 0.72rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.14em;
    color: var(--accent-orange);
    margin-bottom: 0.8rem;
}

.intro-steps,
.intro-notes {
    padding-left: 1.2rem;
    color: var(--text-secondary);
    line-height: 1.7;
}

.intro-steps li,
.intro-notes li { margin-bottom: 0.4rem; }
.intro-steps li strong,
.intro-notes li strong { color: var(--text-primary); }

.intro-scale {
    list-style: none;
    padding: 0;
    display: grid;
    gap: 0.5rem;
}

.intro-scale li {
    display: flex;
    gap: 1rem;
    align-items: center;
    padding: 0.7rem 1rem;
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    color: var(--text-secondary);
    font-size: 0.92rem;
}

.intro-scale .scale-num {
    flex-shrink: 0;
    width: 36px;
    height: 36px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-family: var(--font-display);
    font-weight: 700;
    font-size: 1.05rem;
    background: linear-gradient(135deg, var(--accent-orange), var(--accent-amber));
    color: #fff;
    border-radius: 50%;
}

.intro-scale li strong { color: var(--text-primary); }

.intro-panel kbd {
    display: inline-block;
    padding: 0.05rem 0.4rem;
    font-family: var(--font-mono);
    font-size: 0.78rem;
    background: var(--bg-secondary);
    border: 1px solid var(--border-accent);
    border-radius: 3px;
    color: var(--text-primary);
}

/* ===== Task card CTA (home page) ===== */
.task-card-cta {
    margin-top: 0.8rem;
    font-family: var(--font-mono);
    font-size: 0.78rem;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--accent-orange);
    font-weight: 600;
}

/* ===== Completion / thank-you ===== */
.complete-container {
    text-align: center;
    padding: 5rem 2rem;
    max-width: 680px;
    margin: 0 auto;
}

.complete-icon {
    font-size: 4rem;
    margin-bottom: 1rem;
    color: var(--accent-red);
    animation: heart-pulse 1.8s ease-in-out infinite;
}

@keyframes heart-pulse {
    0%, 100% { transform: scale(1); }
    50%      { transform: scale(1.1); }
}

.complete-thanks {
    color: var(--text-secondary);
    line-height: 1.7;
    margin-top: 1rem;
    font-size: 1rem;
}

.complete-thanks-vi {
    color: var(--accent-amber);
    font-style: italic;
    margin: 1.25rem 0 2rem;
    font-size: 0.95rem;
}

.complete-container h2 {
    font-family: var(--font-display);
    font-weight: 700;
    margin-bottom: 0.5rem;
}

.complete-container p {
    color: var(--text-secondary);
    margin-bottom: 2rem;
}

/* ===== Keyboard shortcut hint ===== */
.shortcut-hint {
    text-align: center;
    font-family: var(--font-mono);
    font-size: 0.75rem;
    color: var(--text-muted);
    margin-top: 0.75rem;
}

kbd {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: 3px;
    padding: 0.15rem 0.5rem;
    font-family: var(--font-mono);
    font-size: 0.8em;
    color: var(--text-secondary);
}

/* ===== Footer ===== */
.site-footer {
    position: relative;
    z-index: 2;
    padding: 3rem 0;
    margin-top: 3rem;
    border-top: 1px solid var(--border);
}

.site-footer .footer-inner {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 1rem;
    font-family: var(--font-mono);
}

.site-footer .footer-text {
    margin: 0;
    font-size: 0.8rem;
    color: var(--text-muted);
    line-height: 1.6;
}

.site-footer .footer-ack {
    flex-basis: 100%;
    margin: 0.25rem 0 0;
    padding-top: 0.9rem;
    border-top: 1px dashed var(--border);
    font-size: 0.8rem;
    color: var(--text-muted);
    line-height: 1.6;
}

/* ===== Responsive ===== */
@media (max-width: 600px) {
    .login-study-meta div { grid-template-columns: 1fr; gap: 0.25rem; }
    .username-row { flex-direction: column; }
    .response-buttons { flex-direction: column; align-items: center; }
    .response-btn { max-width: 100%; }
    .likert-scale { gap: 0.5rem; }
    .likert-circle { width: 44px; height: 44px; font-size: 1.1rem; }
    .tutorial-step { flex-direction: column; }
    .navbar { padding: 0.75rem 1rem; }
    .navbar-links { gap: 0.75rem; }
    .navbar-links a { font-size: 0.7rem; }
}

/* ===== Toast notifications ===== */
#toast-root {
    position: fixed;
    top: 1.5rem;
    right: 1.5rem;
    display: flex;
    flex-direction: column;
    gap: 0.6rem;
    z-index: 9999;
    pointer-events: none;
}
.toast {
    min-width: 260px;
    max-width: 420px;
    padding: 0.8rem 1rem 0.8rem 0.9rem;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-left: 3px solid var(--accent-blue);
    border-radius: var(--radius-lg);
    box-shadow: 0 10px 30px rgba(15, 23, 42, 0.14);
    color: var(--text-primary);
    font-size: 0.88rem;
    line-height: 1.4;
    display: flex;
    gap: 0.7rem;
    align-items: flex-start;
    pointer-events: auto;
    transform: translateX(calc(100% + 2rem));
    opacity: 0;
    transition: transform 0.25s ease, opacity 0.2s ease;
}
.toast.show { transform: translateX(0); opacity: 1; }
.toast.success { border-left-color: var(--accent-cyan); }
.toast.error   { border-left-color: var(--accent-red); }
.toast.warn    { border-left-color: var(--accent-amber); }
.toast.info    { border-left-color: var(--accent-blue); }
.toast-icon {
    flex-shrink: 0;
    width: 20px; height: 20px;
    border-radius: 50%;
    display: inline-flex;
    align-items: center; justify-content: center;
    font-family: var(--font-mono);
    font-size: 0.7rem; font-weight: 700;
    margin-top: 1px;
}
.toast.success .toast-icon { background: rgba(0, 212, 170, 0.15); color: var(--accent-cyan); }
.toast.error   .toast-icon { background: rgba(255, 71, 87, 0.15); color: var(--accent-red); }
.toast.warn    .toast-icon { background: rgba(255, 184, 0, 0.15); color: var(--accent-amber); }
.toast.info    .toast-icon { background: rgba(74, 158, 255, 0.15); color: var(--accent-blue); }
.toast-body { flex: 1; min-width: 0; }
.toast-title {
    font-family: var(--font-display);
    font-weight: 600;
    font-size: 0.92rem;
    margin-bottom: 0.15rem;
    color: var(--text-primary);
}
.toast-msg {
    color: var(--text-secondary);
    font-size: 0.82rem;
    word-break: break-word;
}
.toast-close {
    background: none;
    border: none;
    color: var(--text-muted);
    cursor: pointer;
    font-size: 1rem;
    line-height: 1;
    padding: 0;
    margin-left: 0.3rem;
}
.toast-close:hover { color: var(--text-primary); }

/* ===== Modal dialog ===== */
.modal-backdrop {
    position: fixed;
    inset: 0;
    background: rgba(15, 23, 42, 0.32);
    backdrop-filter: blur(6px);
    z-index: 9998;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.18s ease;
}
.modal-backdrop.show { opacity: 1; pointer-events: auto; }
.modal-dialog {
    width: min(500px, calc(100vw - 2rem));
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    box-shadow: 0 24px 60px rgba(15, 23, 42, 0.2);
    padding: 1.5rem;
    transform: translateY(12px) scale(0.98);
    transition: transform 0.2s ease;
}
.modal-backdrop.show .modal-dialog { transform: translateY(0) scale(1); }
.modal-title {
    font-family: var(--font-display);
    font-weight: 700;
    font-size: 1.15rem;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}
.modal-body {
    color: var(--text-secondary);
    font-size: 0.92rem;
    margin-bottom: 1.25rem;
    white-space: pre-wrap;
}
.modal-body strong { color: var(--text-primary); }
.modal-actions {
    display: flex;
    gap: 0.6rem;
    justify-content: flex-end;
    flex-wrap: wrap;
}

/* ===== Task split layout — image left, rating panel right (no scroll) ===== */
.task-split {
    display: flex;
    gap: 1.75rem;
    align-items: stretch;
    margin: 1.25rem 0;
}
.task-split-image {
    flex: 1 1 auto;
    min-width: 0;
    margin: 0;
}
.task-split-image img {
    max-height: calc(100vh - 220px);
    width: 100%;
    object-fit: contain;
}
.task-split-panel {
    flex: 0 0 260px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    gap: 1rem;
    padding: 1.25rem 1rem;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
}
.task-prompt {
    font-family: var(--font-display);
    font-size: 1rem;
    font-weight: 600;
    text-align: center;
    color: var(--text-primary);
    margin: 0;
}
.likert-vertical {
    flex-direction: column;
    align-items: stretch;
    gap: 0.6rem;
    margin: 0;
}
.likert-vertical .likert-option {
    flex-direction: row;
    align-items: center;
    gap: 0.75rem;
    padding: 0.4rem 0.6rem;
    border-radius: var(--radius);
    cursor: pointer;
    transition: background 0.15s ease;
}
.likert-vertical .likert-option:hover { background: var(--bg-card-hover); }
.likert-vertical .likert-circle {
    width: 42px;
    height: 42px;
    font-size: 1.1rem;
    flex-shrink: 0;
}
.likert-vertical .likert-label {
    text-align: left;
    font-size: 0.75rem;
    color: var(--text-secondary);
    text-transform: none;
    letter-spacing: 0;
}
.likert-vertical .likert-option input:checked ~ .likert-label { color: var(--text-primary); }
.btn-block { width: 100%; }

@media (max-width: 900px) {
    .task-split { flex-direction: column; gap: 1rem; }
    .task-split-panel { flex: 0 0 auto; padding: 1rem; }
    .task-split-image img { max-height: 60vh; }
    .likert-vertical { flex-direction: row; flex-wrap: wrap; justify-content: center; }
    .likert-vertical .likert-option { flex-direction: column; padding: 0.25rem; }
    .likert-vertical .likert-label { text-align: center; font-size: 0.65rem; }
}