/* ==========================================================================
   BioNexus — Biology-Themed 3D Quiz Platform
   ========================================================================== */
@import url('https://fonts.googleapis.com/css2?family=Space+Grotesk:wght@300;400;500;600;700&family=JetBrains+Mono:wght@400;600&display=swap');

:root {
    /* === Bio Color Palette === */
    --bg-dark:         #020c0a;
    --bg-panel:        rgba(4, 26, 18, 0.65);
    --bg-card:         rgba(5, 35, 22, 0.7);

    --bio-green:       #00ff88;
    --bio-green-dim:   rgba(0, 255, 136, 0.15);
    --bio-green-glow:  rgba(0, 255, 136, 0.4);
    --bio-teal:        #00d4aa;
    --bio-teal-dim:    rgba(0, 212, 170, 0.15);
    --bio-lime:        #aaff00;
    --bio-lime-dim:    rgba(170, 255, 0, 0.15);
    --bio-blue:        #00aaff;
    --bio-blue-dim:    rgba(0, 170, 255, 0.15);
    --bio-amber:       #ffaa00;
    --bio-amber-dim:   rgba(255, 170, 0, 0.15);

    --text-main:   #e8faf4;
    --text-muted:  #6d9e89;
    --success:     #00e676;
    --error:       #ff4081;
    --warning:     #ffab40;

    /* Glassmorphism */
    --glass-border:  1px solid rgba(0, 255, 136, 0.12);
    --glass-shadow:  0 8px 40px rgba(0, 0, 0, 0.6), 0 0 60px rgba(0, 255, 136, 0.04);
    --glass-blur:    blur(16px);

    /* Typography */
    --font-primary: 'Space Grotesk', sans-serif;
    --font-mono:    'JetBrains Mono', monospace;

    /* Animation */
    --transition-fast:   0.2s ease;
    --transition-smooth: 0.45s cubic-bezier(0.16, 1, 0.3, 1);
}

/* ==========================================================================
   Base Styles
   ========================================================================== */
* { margin: 0; padding: 0; box-sizing: border-box; }

body {
    font-family: var(--font-primary);
    background-color: var(--bg-dark);
    color: var(--text-main);
    min-height: 100vh;
    overflow-x: hidden;
    line-height: 1.6;
}

/* ==========================================================================
   Background — Bioluminescent Deep-Sea Effect
   ========================================================================== */
.bg-elements {
    position: fixed;
    inset: 0;
    z-index: -1;
    overflow: hidden;
    pointer-events: none;
}

/* Deep-sea dark green gradient base */
.bg-elements::before {
    content: '';
    position: absolute;
    inset: 0;
    background:
        radial-gradient(ellipse 80% 60% at 20% 10%,  rgba(0,180,80,0.07) 0%, transparent 70%),
        radial-gradient(ellipse 60% 80% at 80% 90%,  rgba(0,80,200,0.06) 0%, transparent 70%),
        radial-gradient(ellipse 100% 100% at 50% 50%, rgba(0,40,20,0.8) 0%, #020c0a 100%);
}

.glow-orb {
    position: absolute;
    border-radius: 50%;
    filter: blur(80px);
    opacity: 0.35;
    animation: float 22s infinite alternate ease-in-out;
}

.orb-1 {
    width: 500px; height: 500px;
    background: radial-gradient(circle, var(--bio-green) 0%, transparent 65%);
    top: -150px; left: -150px;
}
.orb-2 {
    width: 600px; height: 600px;
    background: radial-gradient(circle, var(--bio-teal) 0%, transparent 65%);
    bottom: -200px; right: -150px;
    animation-delay: -8s;
}
.orb-3 {
    width: 350px; height: 350px;
    background: radial-gradient(circle, var(--bio-lime) 0%, transparent 65%);
    top: 35%; left: 40%;
    opacity: 0.12;
    animation-delay: -14s;
}

/* Hexagonal cell-wall grid */
.grid-overlay {
    position: absolute;
    inset: 0;
    background-image:
        linear-gradient(rgba(0, 255, 136, 0.03) 1px, transparent 1px),
        linear-gradient(90deg, rgba(0, 255, 136, 0.03) 1px, transparent 1px);
    background-size: 40px 40px;
    mask-image: radial-gradient(ellipse at center, black 40%, transparent 80%);
    -webkit-mask-image: radial-gradient(ellipse at center, black 40%, transparent 80%);
}

/* Floating DNA Particles */
.dna-particles {
    position: absolute;
    inset: 0;
}
.dna-particle {
    position: absolute;
    border-radius: 50%;
    background: var(--bio-green);
    opacity: 0;
    animation: particle-float linear infinite;
}

@keyframes particle-float {
    0%   { opacity: 0; transform: translateY(0) scale(0); }
    10%  { opacity: 0.6; transform: translateY(-10px) scale(1); }
    90%  { opacity: 0.3; }
    100% { opacity: 0; transform: translateY(-120px) scale(0.3); }
}

@keyframes float {
    0%   { transform: translate(0, 0) scale(1); }
    100% { transform: translate(60px, 60px) scale(1.05); }
}

/* DNA Helix Sidebar Decoration */
.dna-helix {
    position: absolute;
    right: 2%;
    top: 50%;
    transform: translateY(-50%);
    width: 60px;
    height: 80vh;
    opacity: 0.15;
}

/* ==========================================================================
   Glassmorphism Utility — Bio Edition
   ========================================================================== */
.glass-panel {
    background: var(--bg-panel);
    backdrop-filter: var(--glass-blur);
    -webkit-backdrop-filter: var(--glass-blur);
    border: var(--glass-border);
    box-shadow: var(--glass-shadow);
    border-radius: 20px;
    position: relative;
    overflow: hidden;
}

/* Top shimmer line on glass panels */
.glass-panel::before {
    content: '';
    position: absolute;
    top: 0; left: 10%; right: 10%;
    height: 1px;
    background: linear-gradient(90deg, transparent, var(--bio-green), transparent);
    opacity: 0.5;
}

/* ==========================================================================
   3D Card Effect
   ========================================================================== */
.card-3d {
    transform-style: preserve-3d;
    perspective: 800px;
    transition: transform var(--transition-smooth);
}
.card-3d:hover {
    transform: rotateX(-2deg) rotateY(2deg) translateZ(6px);
}

/* ==========================================================================
   Typography
   ========================================================================== */
h1, h2, h3, h4 {
    font-weight: 700;
    margin-bottom: 0.5rem;
    letter-spacing: -0.02em;
}

.bio-text {
    color: var(--bio-green);
    text-shadow: 0 0 12px var(--bio-green-glow);
}

.bio-text-teal {
    color: var(--bio-teal);
    text-shadow: 0 0 12px rgba(0,212,170,0.4);
}

.neon-text {
    color: var(--bio-green);
    text-shadow: 0 0 10px var(--bio-green-glow);
}

.neon-text-large {
    font-size: 3.5rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--bio-green), var(--bio-teal), var(--bio-lime));
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    filter: drop-shadow(0 0 20px rgba(0, 255, 136, 0.3));
}

.mono { font-family: var(--font-mono); }

/* Color helpers */
.green  { color: var(--success); }
.red    { color: var(--error); }
.teal   { color: var(--bio-teal); }
.lime   { color: var(--bio-lime); }
.amber  { color: var(--bio-amber); }
.blue   { color: var(--bio-blue); }
.muted  { color: var(--text-muted); }

/* ==========================================================================
   Header / Navigation
   ========================================================================== */
header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 2rem;
    margin: 1rem 2rem;
    position: relative;
    z-index: 10;
}

/* ---- Logo ---- */
.logo {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    text-decoration: none;
    cursor: default;
}

.logo-icon-wrap {
    position: relative;
    width: 44px;
    height: 44px;
    display: flex;
    align-items: center;
    justify-content: center;
}

/* Rotating orbit ring around logo icon */
.logo-icon-wrap::before {
    content: '';
    position: absolute;
    inset: -4px;
    border-radius: 50%;
    border: 2px solid transparent;
    border-top-color: var(--bio-green);
    border-right-color: var(--bio-teal);
    animation: orbit 3s linear infinite;
}

@keyframes orbit {
    to { transform: rotate(360deg); }
}

.logo-icon-wrap .fa-dna {
    font-size: 1.5rem;
    color: var(--bio-green);
    filter: drop-shadow(0 0 10px var(--bio-green-glow));
    animation: dna-pulse 3s ease-in-out infinite;
    position: relative;
    z-index: 1;
}

@keyframes dna-pulse {
    0%, 100% { transform: scale(1); filter: drop-shadow(0 0 10px var(--bio-green-glow)); }
    50%       { transform: scale(1.15); filter: drop-shadow(0 0 18px var(--bio-green-glow)); }
}

.logo-text-wrap {
    display: flex;
    flex-direction: column;
    line-height: 1;
}

.logo-name {
    font-size: 1.4rem;
    font-weight: 700;
    letter-spacing: 3px;
    background: linear-gradient(135deg, var(--bio-green), var(--bio-teal));
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.logo-tagline {
    font-size: 0.6rem;
    font-family: var(--font-mono);
    letter-spacing: 2px;
    color: var(--text-muted);
    text-transform: uppercase;
}

/* ---- Nav Buttons ---- */
nav { display: flex; gap: 0.75rem; }

.nav-btn {
    background: transparent;
    border: 1px solid transparent;
    color: var(--text-muted);
    font-family: var(--font-primary);
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    padding: 0.5rem 1.1rem;
    border-radius: 10px;
    transition: var(--transition-fast);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}
.nav-btn:hover {
    color: var(--text-main);
    background: rgba(0,255,136,0.06);
    border-color: rgba(0,255,136,0.15);
}
.nav-btn.active {
    color: var(--bio-green);
    background: var(--bio-green-dim);
    border-color: rgba(0,255,136,0.3);
    box-shadow: 0 0 12px rgba(0,255,136,0.1), inset 0 0 8px rgba(0,255,136,0.05);
}

/* ==========================================================================
   Main Container & Screens
   ========================================================================== */
#app-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem;
    position: relative;
    z-index: 5;
    min-height: calc(100vh - 100px);
    display: flex;
    flex-direction: column;
}

.screen {
    display: none;
    opacity: 0;
    animation: bioFadeIn var(--transition-smooth) forwards;
    flex: 1;
    flex-direction: column;
}
.screen.active { display: flex; }

@keyframes bioFadeIn {
    from { opacity: 0; transform: translateY(16px) scale(0.99); }
    to   { opacity: 1; transform: translateY(0) scale(1); }
}

/* ==========================================================================
   Buttons
   ========================================================================== */
.btn-primary, .btn-secondary {
    font-family: var(--font-primary);
    font-weight: 600;
    font-size: 0.95rem;
    padding: 0.8rem 1.6rem;
    border-radius: 12px;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    transition: var(--transition-fast);
    border: none;
    letter-spacing: 0.02em;
}

.btn-primary {
    background: linear-gradient(135deg, var(--bio-green), var(--bio-teal));
    color: #010e08;
    font-weight: 700;
    box-shadow: 0 4px 20px rgba(0,255,136,0.2);
}
.btn-primary:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 8px 30px rgba(0,255,136,0.35);
}

.btn-secondary {
    background: rgba(0,255,136,0.05);
    color: var(--text-main);
    border: 1px solid rgba(0,255,136,0.15);
}
.btn-secondary:hover:not(:disabled) {
    background: rgba(0,255,136,0.1);
    border-color: rgba(0,255,136,0.3);
}

.glow-btn:not(:disabled):hover {
    transform: translateY(-3px);
    box-shadow: 0 0 25px var(--bio-green-glow);
}

button:disabled {
    opacity: 0.4;
    cursor: not-allowed;
    filter: grayscale(0.6);
}

.icon-btn {
    background: transparent;
    border: 1px solid rgba(0,255,136,0.15);
    color: var(--text-main);
    font-size: 1.1rem;
    cursor: pointer;
    width: 40px; height: 40px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition-fast);
}
.icon-btn:hover {
    background: var(--bio-green-dim);
    border-color: var(--bio-green);
    color: var(--bio-green);
}

.hidden { display: none !important; }

/* ==========================================================================
   Screen: Loading
   ========================================================================== */
#screen-loading {
    align-items: center;
    justify-content: center;
    text-align: center;
}

.loader-container {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1.5rem;
}

/* Bio-cell spinner */
.spinner {
    width: 70px; height: 70px;
    position: relative;
}
.spinner::before, .spinner::after {
    content: '';
    position: absolute;
    border-radius: 50%;
}
.spinner::before {
    inset: 0;
    border: 3px solid rgba(0,255,136,0.1);
    border-top-color: var(--bio-green);
    animation: spin 1.1s linear infinite;
}
.spinner::after {
    inset: 10px;
    border: 2px solid rgba(0,212,170,0.1);
    border-bottom-color: var(--bio-teal);
    animation: spin 0.8s linear infinite reverse;
}

@keyframes spin { to { transform: rotate(360deg); } }

.loader-container h2 {
    font-family: var(--font-mono);
    font-size: 1rem;
    color: var(--bio-green);
    letter-spacing: 2px;
}
.loader-container p {
    color: var(--text-muted);
    font-family: var(--font-mono);
    font-size: 0.8rem;
}

/* ==========================================================================
   Screen: Filter (Home)
   ========================================================================== */
#screen-filter { padding: 2.5rem; }

.header-content {
    margin-bottom: 2.5rem;
    text-align: center;
}
.header-content h1 {
    font-size: 2rem;
    background: linear-gradient(135deg, var(--bio-green), var(--bio-teal));
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}
.header-content p { color: var(--text-muted); margin-top: 0.5rem; }

.filter-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.filter-group {
    background: var(--bg-card);
    padding: 1.5rem;
    border-radius: 16px;
    border: 1px solid rgba(0,255,136,0.08);
    transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}
.filter-group:hover {
    border-color: rgba(0,255,136,0.2);
    box-shadow: 0 0 20px rgba(0,255,136,0.05);
}

.filter-group label {
    display: flex;
    align-items: center;
    gap: 0.6rem;
    margin-bottom: 1.2rem;
    font-weight: 600;
    color: var(--bio-green);
    font-size: 0.9rem;
    letter-spacing: 0.05em;
    text-transform: uppercase;
}
.filter-group label i { font-size: 1rem; }

.checkbox-grid {
    display: flex;
    flex-wrap: wrap;
    gap: 0.6rem;
    max-height: 200px;
    overflow-y: auto;
    padding-right: 0.25rem;
}

/* Scrollbar */
::-webkit-scrollbar { width: 5px; }
::-webkit-scrollbar-track { background: rgba(0,0,0,0.2); border-radius: 4px; }
::-webkit-scrollbar-thumb { background: rgba(0,255,136,0.2); border-radius: 4px; }
::-webkit-scrollbar-thumb:hover { background: var(--bio-green); }

.checkbox-item { position: relative; cursor: pointer; }
.checkbox-item input { position: absolute; opacity: 0; cursor: pointer; }

.checkmark {
    display: inline-block;
    padding: 0.35rem 0.75rem;
    background: rgba(0,255,136,0.04);
    border: 1px solid rgba(0,255,136,0.12);
    border-radius: 20px;
    font-size: 0.82rem;
    font-family: var(--font-mono);
    transition: var(--transition-fast);
    user-select: none;
    color: var(--text-muted);
}
.checkbox-item:hover input ~ .checkmark {
    background: rgba(0,255,136,0.08);
    border-color: rgba(0,255,136,0.25);
    color: var(--text-main);
}
.checkbox-item input:checked ~ .checkmark {
    background: var(--bio-green-dim);
    border-color: var(--bio-green);
    color: var(--bio-green);
    box-shadow: 0 0 10px rgba(0,255,136,0.15);
}

.range-container {
    display: flex;
    align-items: center;
    gap: 1rem;
}

input[type=range] {
    flex: 1;
    -webkit-appearance: none;
    background: rgba(0,255,136,0.1);
    height: 5px;
    border-radius: 3px;
    outline: none;
}
input[type=range]::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 22px; height: 22px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--bio-green), var(--bio-teal));
    cursor: pointer;
    box-shadow: 0 0 12px var(--bio-green-glow);
    border: 2px solid rgba(0,0,0,0.3);
}

.action-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: auto;
    padding-top: 2rem;
    border-top: 1px solid rgba(0,255,136,0.08);
}

/* Stats preview */
.stats-preview {
    font-family: var(--font-mono);
    font-size: 0.85rem;
    color: var(--text-muted);
    background: var(--bio-green-dim);
    border: 1px solid rgba(0,255,136,0.2);
    padding: 0.5rem 1rem;
    border-radius: 8px;
}
.stats-preview .neon-text { font-weight: 700; font-size: 1rem; }

/* ==========================================================================
   Screen: Quiz
   ========================================================================== */
.quiz-header {
    padding: 1.25rem 1.75rem;
    margin-bottom: 1.75rem;
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.progress-container { display: flex; flex-direction: column; gap: 0.5rem; }

.progress-bar {
    height: 6px;
    background: rgba(0,255,136,0.1);
    border-radius: 3px;
    overflow: hidden;
}
.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--bio-green), var(--bio-teal), var(--bio-lime));
    width: 0%;
    transition: width var(--transition-smooth);
    box-shadow: 0 0 8px var(--bio-green-glow);
    border-radius: 3px;
}

.progress-stats {
    display: flex;
    justify-content: space-between;
    font-size: 0.82rem;
    color: var(--text-muted);
    font-family: var(--font-mono);
}

.meta-badges { display: flex; gap: 0.5rem; flex-wrap: wrap; }

.badge {
    padding: 0.2rem 0.7rem;
    border-radius: 6px;
    font-size: 0.7rem;
    font-weight: 600;
    font-family: var(--font-mono);
    text-transform: uppercase;
    letter-spacing: 1px;
}
.badge-cyan   { background: var(--bio-blue-dim);  color: var(--bio-blue);  border: 1px solid rgba(0,170,255,0.3); }
.badge-purple { background: var(--bio-lime-dim);  color: var(--bio-lime);  border: 1px solid rgba(170,255,0,0.3); }

.question-container {
    padding: 2.5rem;
    margin-bottom: 1.75rem;
    flex: 1;
    display: flex;
    flex-direction: column;
}

.question-text {
    font-size: 1.4rem;
    margin-bottom: 2rem;
    line-height: 1.5;
    font-weight: 500;
}

.options-grid {
    display: flex;
    flex-direction: column;
    gap: 0.85rem;
}

/* === 3D Option Cards === */
.option-card {
    background: rgba(0,255,136,0.02);
    border: 1px solid rgba(0,255,136,0.1);
    border-radius: 14px;
    padding: 1rem 1.4rem;
    cursor: pointer;
    transition: all var(--transition-fast);
    display: flex;
    align-items: center;
    gap: 1rem;
    position: relative;
    overflow: hidden;
    transform-style: preserve-3d;
}

/* Animated shimmer on hover */
.option-card::after {
    content: '';
    position: absolute;
    top: 0; left: -100%;
    width: 60%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(0,255,136,0.06), transparent);
    transition: left 0.4s ease;
    pointer-events: none;
}

.option-card:hover::after { left: 140%; }

.option-card::before {
    content: '';
    position: absolute;
    left: 0; top: 0;
    height: 100%;
    width: 3px;
    background: transparent;
    transition: var(--transition-fast);
    border-radius: 2px 0 0 2px;
}

.option-card:hover {
    background: rgba(0,255,136,0.06);
    border-color: rgba(0,255,136,0.25);
    transform: translateX(5px) translateZ(4px);
    box-shadow: 0 4px 20px rgba(0,0,0,0.3), 0 0 15px rgba(0,255,136,0.06);
}

.option-card.selected {
    background: var(--bio-green-dim);
    border-color: var(--bio-green);
    box-shadow: 0 0 20px rgba(0,255,136,0.12), inset 0 0 12px rgba(0,255,136,0.04);
}
.option-card.selected::before { background: var(--bio-green); }

.option-indicator {
    width: 26px; height: 26px;
    border-radius: 8px;
    border: 2px solid rgba(0,255,136,0.2);
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
    transition: var(--transition-fast);
    font-family: var(--font-mono);
    font-size: 0.75rem;
    color: var(--text-muted);
}
.option-card.selected .option-indicator {
    background: var(--bio-green);
    border-color: var(--bio-green);
    color: #010e08;
    font-weight: 700;
    box-shadow: 0 0 10px var(--bio-green-glow);
}
.option-card.selected .option-indicator i { opacity: 1; }
.option-indicator i { opacity: 0; font-size: 0.75rem; transition: opacity var(--transition-fast); }

/* Post-submission states */
.option-card.correct-answer {
    background: rgba(0,230,118,0.1);
    border-color: var(--success);
    box-shadow: 0 0 16px rgba(0,230,118,0.15);
}
.option-card.correct-answer::before { background: var(--success); }
.option-card.correct-answer .option-indicator {
    background: var(--success); border-color: var(--success); color: #010e08;
}
.option-card.correct-answer .option-indicator i { opacity: 1; }

.option-card.wrong-answer {
    background: rgba(255,64,129,0.08);
    border-color: var(--error);
    box-shadow: 0 0 16px rgba(255,64,129,0.1);
}
.option-card.wrong-answer::before { background: var(--error); }
.option-card.wrong-answer .option-indicator { background: var(--error); border-color: var(--error); color: #fff; }
.option-card.wrong-answer .option-indicator i::before { content: "\f00d"; }
.option-card.wrong-answer .option-indicator i { opacity: 1; }

/* Quiz Controls */
.quiz-controls {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.feedback-panel {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 0.8rem 1.4rem;
    border-radius: 12px;
    background: rgba(0,0,0,0.35);
    border-left: 4px solid transparent;
    backdrop-filter: blur(8px);
}
.feedback-panel.correct  { border-left-color: var(--success); }
.feedback-panel.correct .feedback-icon { color: var(--success); }
.feedback-panel.incorrect { border-left-color: var(--error); }
.feedback-panel.incorrect .feedback-icon { color: var(--error); }
.feedback-panel.incorrect .feedback-icon i::before { content: "\f00d"; }
.feedback-content h4 { margin: 0; font-size: 0.95rem; }
.feedback-content p  { margin: 0; font-size: 0.82rem; color: var(--text-muted); }

/* ==========================================================================
   Screen: Results
   ========================================================================== */
#screen-result {
    padding: 3rem;
    align-items: center;
    text-align: center;
}

.result-header h1 {
    font-size: 2rem;
    background: linear-gradient(135deg, var(--bio-green), var(--bio-teal));
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}
.result-header p { color: var(--text-muted); margin-top: 0.25rem; }

/* Score Circle with 3D glow */
.score-circle-container {
    position: relative;
    width: 220px; height: 220px;
    margin: 2rem auto;
    filter: drop-shadow(0 0 30px rgba(0,255,136,0.2));
}
.score-circle { width: 100%; height: 100%; transform: rotate(-90deg); }

.circle-bg    { fill: none; stroke: rgba(0,255,136,0.08); stroke-width: 7; }
.circle-progress {
    fill: none;
    stroke: var(--bio-green);
    stroke-width: 7;
    stroke-dasharray: 283;
    stroke-dashoffset: 283;
    stroke-linecap: round;
    transition: stroke-dashoffset 1.6s cubic-bezier(0.4, 0, 0.2, 1);
}

.score-content {
    position: absolute;
    top: 50%; left: 50%;
    transform: translate(-50%, -50%);
    display: flex;
    flex-direction: column;
    align-items: center;
}

.metrics-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: 1.25rem;
    width: 100%;
    max-width: 820px;
    margin: 2rem 0;
}

.metric-card {
    background: var(--bg-card);
    border: 1px solid rgba(0,255,136,0.08);
    border-radius: 16px;
    padding: 1.4rem;
    display: flex;
    align-items: center;
    gap: 1rem;
    transition: all var(--transition-fast);
}
.metric-card:hover {
    border-color: rgba(0,255,136,0.2);
    transform: translateY(-3px);
    box-shadow: 0 8px 24px rgba(0,0,0,0.3), 0 0 16px rgba(0,255,136,0.06);
}

.metric-icon {
    font-size: 1.6rem;
    width: 48px; height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 12px;
    background: rgba(0,255,136,0.06);
    flex-shrink: 0;
}
.metric-icon.green  { color: var(--success);   background: rgba(0,230,118,0.1); }
.metric-icon.red    { color: var(--error);     background: rgba(255,64,129,0.1); }
.metric-icon.teal   { color: var(--bio-teal);  background: var(--bio-teal-dim); }
.metric-icon.cyan   { color: var(--bio-green); background: var(--bio-green-dim); }

.metric-info { display: flex; flex-direction: column; text-align: left; }
.metric-label { font-size: 0.8rem; color: var(--text-muted); font-family: var(--font-mono); text-transform: uppercase; letter-spacing: 0.05em; }
.metric-value { font-size: 1.3rem; font-weight: 700; margin-top: 0.15rem; }

.result-actions {
    width: 100%; max-width: 820px;
    justify-content: center;
    gap: 1.5rem;
}

/* ==========================================================================
   Screen: Review
   ========================================================================== */
#screen-review { padding: 2rem; }

.review-header {
    display: flex;
    align-items: center;
    justify-content: flex-start;
    gap: 1rem;
    text-align: left;
    margin-bottom: 1.5rem;
}
.review-header h1 { margin: 0; flex: 1; }

.review-filters {
    display: flex;
    background: rgba(0,0,0,0.3);
    border-radius: 10px;
    padding: 0.25rem;
    border: 1px solid rgba(0,255,136,0.08);
}
.review-filter-btn {
    background: transparent;
    border: none;
    color: var(--text-muted);
    padding: 0.4rem 0.9rem;
    border-radius: 8px;
    cursor: pointer;
    font-family: var(--font-primary);
    font-size: 0.85rem;
    transition: var(--transition-fast);
}
.review-filter-btn.active {
    background: var(--bio-green-dim);
    color: var(--bio-green);
    border: 1px solid rgba(0,255,136,0.25);
}

.search-bar {
    position: relative;
    margin-bottom: 1.5rem;
}
.search-bar i {
    position: absolute;
    left: 1rem;
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-muted);
}
.search-bar input {
    width: 100%;
    background: var(--bg-card);
    border: 1px solid rgba(0,255,136,0.1);
    border-radius: 12px;
    padding: 0.9rem 1rem 0.9rem 2.75rem;
    color: var(--text-main);
    font-family: var(--font-primary);
    font-size: 0.95rem;
    outline: none;
    transition: var(--transition-fast);
}
.search-bar input:focus {
    border-color: rgba(0,255,136,0.35);
    box-shadow: 0 0 14px rgba(0,255,136,0.08);
}

.review-list {
    display: flex;
    flex-direction: column;
    gap: 1.25rem;
    overflow-y: auto;
    padding-right: 0.5rem;
    max-height: 60vh;
}

.review-card {
    background: var(--bg-card);
    border: 1px solid rgba(0,255,136,0.07);
    border-radius: 14px;
    padding: 1.5rem;
    border-left: 4px solid transparent;
    transition: all var(--transition-fast);
}
.review-card:hover {
    transform: translateX(4px);
    box-shadow: 0 4px 20px rgba(0,0,0,0.3);
}
.review-card.correct   { border-left-color: var(--success); }
.review-card.incorrect { border-left-color: var(--error); }

.review-question {
    font-weight: 500;
    margin-bottom: 1rem;
    line-height: 1.5;
}

.review-options {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 0.5rem;
}
.review-option {
    padding: 0.5rem 0.9rem;
    border-radius: 8px;
    font-size: 0.85rem;
    background: rgba(0,255,136,0.02);
    border: 1px solid transparent;
    color: var(--text-muted);
}
.review-option.correct {
    background: rgba(0,230,118,0.08);
    border-color: rgba(0,230,118,0.3);
    color: var(--success);
}
.review-option.user-wrong {
    background: rgba(255,64,129,0.08);
    border-color: rgba(255,64,129,0.3);
    color: var(--error);
    text-decoration: line-through;
}

/* ==========================================================================
   Screen: Scoreboard
   ========================================================================== */
#screen-scoreboard { padding: 2.5rem; }

.stats-overview {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1.25rem;
    margin-bottom: 2.5rem;
}

.stat-box {
    background: var(--bg-card);
    border: 1px solid rgba(0,255,136,0.08);
    border-radius: 18px;
    padding: 2rem;
    text-align: center;
    position: relative;
    overflow: hidden;
    transition: all var(--transition-fast);
    cursor: default;
}
.stat-box:hover {
    border-color: rgba(0,255,136,0.2);
    transform: translateY(-4px);
    box-shadow: 0 12px 32px rgba(0,0,0,0.4), 0 0 20px rgba(0,255,136,0.06);
}
/* Top glow bar */
.stat-box::after {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0;
    height: 2px;
    background: linear-gradient(90deg, transparent, var(--bio-green), transparent);
    opacity: 0.6;
}

/* 3D hexagon accent */
.stat-box::before {
    content: '';
    position: absolute;
    bottom: -40px; right: -40px;
    width: 100px; height: 100px;
    border: 2px solid rgba(0,255,136,0.05);
    border-radius: 20px;
    transform: rotate(30deg);
}

.stat-icon {
    font-size: 1.75rem;
    color: var(--bio-green);
    margin-bottom: 1rem;
    filter: drop-shadow(0 0 8px var(--bio-green-glow));
}
.stat-value {
    font-size: 2.4rem;
    font-weight: 700;
    margin-bottom: 0.25rem;
    font-family: var(--font-mono);
}
.stat-label {
    font-size: 0.75rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.08em;
    font-family: var(--font-mono);
}

.recent-sessions {
    background: var(--bg-card);
    border-radius: 18px;
    padding: 2rem;
    border: 1px solid rgba(0,255,136,0.08);
}
.recent-sessions h3 {
    font-size: 0.85rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--bio-green);
    margin-bottom: 0;
    font-family: var(--font-mono);
}

.sessions-list {
    margin-top: 1.5rem;
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.session-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.9rem 1.2rem;
    background: rgba(0,255,136,0.02);
    border-radius: 10px;
    border-left: 3px solid var(--bio-green);
    border: 1px solid rgba(0,255,136,0.08);
    border-left: 3px solid var(--bio-green);
    transition: all var(--transition-fast);
}
.session-item:hover {
    background: rgba(0,255,136,0.05);
    transform: translateX(4px);
}
.session-date  { color: var(--text-muted); font-size: 0.82rem; font-family: var(--font-mono); }
.session-score { font-weight: 700; font-size: 1.05rem; color: var(--bio-green); }

.empty-state {
    text-align: center;
    padding: 3rem 2rem;
    color: var(--text-muted);
    font-style: italic;
    font-family: var(--font-mono);
    font-size: 0.9rem;
}

/* ==========================================================================
   Toasts
   ========================================================================== */
.toast-container {
    position: fixed;
    bottom: 2rem; right: 2rem;
    z-index: 1000;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}
.toast {
    background: rgba(4,26,18,0.95);
    backdrop-filter: blur(12px);
    border-left: 4px solid var(--bio-green);
    color: var(--text-main);
    padding: 1rem 1.5rem;
    border-radius: 12px;
    box-shadow: 0 4px 20px rgba(0,0,0,0.4), 0 0 20px rgba(0,255,136,0.08);
    animation: slideInRight 0.35s forwards;
    display: flex;
    align-items: center;
    gap: 0.75rem;
    font-size: 0.9rem;
    border: 1px solid rgba(0,255,136,0.15);
}
.toast.error   { border-left-color: var(--error); }
.toast.success { border-left-color: var(--success); }

@keyframes slideInRight {
    from { transform: translateX(110%); opacity: 0; }
    to   { transform: translateX(0);   opacity: 1; }
}
@keyframes fadeOut {
    to { opacity: 0; transform: translateX(20px); }
}

/* ==========================================================================
   Biological Accent Elements (SVG Helix)
   ========================================================================== */
.bio-accent-dots {
    display: flex;
    align-items: center;
    gap: 0.4rem;
    margin: 0.75rem 0;
}
.bio-accent-dots span {
    display: inline-block;
    width: 6px; height: 6px;
    border-radius: 50%;
    background: var(--bio-green);
    opacity: 0.4;
    animation: dot-pulse 1.5s ease-in-out infinite;
}
.bio-accent-dots span:nth-child(2) { animation-delay: 0.2s; background: var(--bio-teal); }
.bio-accent-dots span:nth-child(3) { animation-delay: 0.4s; background: var(--bio-lime); }
@keyframes dot-pulse {
    0%, 100% { transform: scale(1); opacity: 0.4; }
    50%       { transform: scale(1.6); opacity: 1; }
}

/* ==========================================================================
   Media Queries
   ========================================================================== */
@media (max-width: 768px) {
    header { margin: 0; padding: 0.75rem 1rem; }
    .logo-tagline { display: none; }
    #app-container { padding: 1rem; }
    .filter-grid { grid-template-columns: 1fr; }
    .action-footer { flex-direction: column; gap: 1rem; text-align: center; }
    .quiz-controls { flex-direction: column-reverse; gap: 1rem; }
    .quiz-controls button { width: 100%; }
    .feedback-panel { width: 100%; justify-content: center; }
    .metrics-grid { grid-template-columns: 1fr 1fr; }
    .review-header { flex-direction: column; align-items: flex-start; }
    .stats-overview { grid-template-columns: 1fr 1fr; }
    .question-text { font-size: 1.15rem; }
    .neon-text-large { font-size: 2.5rem; }
}

@media (max-width: 480px) {
    .stats-overview { grid-template-columns: 1fr; }
    .metrics-grid { grid-template-columns: 1fr; }
    .score-circle-container { width: 160px; height: 160px; }
    .result-actions { flex-direction: column; align-items: stretch; }
    .result-actions button { width: 100%; }
}