:root {
    --bg: #0a0b0e;
    --bg2: #0f1117;
    --bg3: #161820;
    --surface: #1a1d26;
    --surface2: #22253300;
    --border: #2a2d3a;
    --border2: #363a4d;
    --accent: #00e5ff;
    --accent2: #7b5ea7;
    --accent3: #ff4d6d;
    --green: #00ffa3;
    --yellow: #ffd166;
    --text: #e2e4ed;
    --text2: #8b8fa8;
    --text3: #555870;
    --mono: 'JetBrains Mono', monospace;
    --sans: 'Syne', sans-serif;
    --mono2: 'Space Mono', monospace;
    --radius: 8px;
    --radius2: 4px;
    --topbar-h: 56px;
    --sidebar-w: 240px;
    --sidebar-w-collapsed: 0px;
    --transition: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

*,
*::before,
*::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
}

body {
    background: var(--bg);
    color: var(--text);
    font-family: var(--sans);
    font-size: 15px;
    line-height: 1.6;
    overflow-x: hidden;
    min-height: 100vh;
}

::-webkit-scrollbar {
    width: 6px;
    height: 6px;
}

::-webkit-scrollbar-track {
    background: var(--bg2);
}

::-webkit-scrollbar-thumb {
    background: var(--border2);
    border-radius: 3px;
}

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

#boot-splash {
    position: fixed;
    inset: 0;
    z-index: 9999;
    background: var(--bg);
    display: flex;
    align-items: center;
    justify-content: center;
    transition: opacity 0.5s ease, visibility 0.5s ease;
}

#boot-splash.fade-out {
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
}

.boot-inner {
    text-align: center;
    width: 320px;
}

.boot-logo {
    font-family: var(--mono);
    font-size: 3rem;
    font-weight: 700;
    letter-spacing: -2px;
    color: var(--text);
    margin-bottom: 6px;
}

.boot-sub {
    font-family: var(--mono);
    font-size: 0.7rem;
    color: var(--text3);
    letter-spacing: 3px;
    text-transform: uppercase;
    margin-bottom: 40px;
}

.boot-bar-wrap {
    width: 100%;
    height: 2px;
    background: var(--border);
    border-radius: 2px;
    overflow: hidden;
    margin-bottom: 16px;
}

.boot-bar {
    height: 100%;
    width: 0%;
    background: linear-gradient(90deg, var(--accent2), var(--accent));
    border-radius: 2px;
    animation: boot-load 2s ease forwards;
    box-shadow: 0 0 12px var(--accent);
}

@keyframes boot-load {
    0% {
        width: 0%;
    }

    60% {
        width: 75%;
    }

    85% {
        width: 90%;
    }

    100% {
        width: 100%;
    }
}

.boot-status {
    font-family: var(--mono);
    font-size: 0.7rem;
    color: var(--text3);
    min-height: 1rem;
}

.hidden {
    display: none !important;
}

.topbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: var(--topbar-h);
    background: var(--bg2);
    border-bottom: 1px solid var(--border);
    display: flex;
    align-items: center;
    padding: 0 20px;
    gap: 16px;
    z-index: 100;
    backdrop-filter: blur(12px);
}

.topbar-left {
    display: flex;
    align-items: center;
    gap: 14px;
    min-width: 200px;
}

.brand {
    font-family: var(--mono);
    font-size: 1rem;
    font-weight: 700;
    letter-spacing: -0.5px;
    color: var(--text);
}

.accent {
    color: var(--accent);
}

.sidebar-toggle {
    background: none;
    border: none;
    cursor: pointer;
    display: flex;
    flex-direction: column;
    gap: 5px;
    padding: 6px 4px;
}

.sidebar-toggle span {
    display: block;
    width: 20px;
    height: 2px;
    background: var(--text2);
    border-radius: 2px;
    transition: var(--transition);
}

.sidebar-toggle:hover span {
    background: var(--accent);
}

.topbar-nav {
    display: flex;
    gap: 4px;
    flex: 1;
    justify-content: center;
}

.nav-btn {
    background: none;
    border: none;
    color: var(--text2);
    font-family: var(--mono);
    font-size: 0.75rem;
    letter-spacing: 0.5px;
    padding: 6px 14px;
    border-radius: var(--radius2);
    cursor: pointer;
    transition: var(--transition);
    text-transform: uppercase;
}

.nav-btn:hover {
    color: var(--text);
    background: var(--surface);
}

.nav-btn.active {
    color: var(--accent);
    background: rgba(0, 229, 255, 0.07);
}

.topbar-right {
    display: flex;
    align-items: center;
    gap: 12px;
    min-width: 180px;
    justify-content: flex-end;
}

.exam-countdown {
    display: flex;
    align-items: baseline;
    gap: 6px;
    font-family: var(--mono);
    font-size: 0.72rem;
}

.countdown-label {
    color: var(--text3);
}

.countdown-value {
    color: var(--yellow);
    font-weight: 700;
}

.status-dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: var(--green);
    box-shadow: 0 0 6px var(--green);
    animation: pulse-dot 2s ease-in-out infinite;
}

@keyframes pulse-dot {

    0%,
    100% {
        opacity: 1;
    }

    50% {
        opacity: 0.4;
    }
}

.layout {
    display: flex;
    padding-top: var(--topbar-h);
    min-height: 100vh;
}

.sidebar {
    width: var(--sidebar-w);
    flex-shrink: 0;
    background: var(--bg2);
    border-right: 1px solid var(--border);
    display: flex;
    flex-direction: column;
    position: fixed;
    top: var(--topbar-h);
    left: 0;
    bottom: 0;
    overflow-y: auto;
    overflow-x: hidden;
    transition: width var(--transition), transform var(--transition);
    z-index: 90;
    padding-bottom: 80px;
}

.sidebar.collapsed {
    width: 0;
    transform: translateX(-100%);
}

.sidebar-section {
    padding: 20px 0 8px;
    border-bottom: 1px solid var(--border);
}

.sidebar-section:last-of-type {
    border-bottom: none;
}

.sidebar-label {
    font-family: var(--mono);
    font-size: 0.6rem;
    letter-spacing: 2px;
    text-transform: uppercase;
    color: var(--text3);
    padding: 0 16px 10px;
}

.sidebar-list {
    list-style: none;
}

.sidebar-item {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 9px 16px;
    cursor: pointer;
    font-family: var(--mono);
    font-size: 0.78rem;
    color: var(--text2);
    border-left: 2px solid transparent;
    transition: var(--transition);
    white-space: nowrap;
}

.sidebar-item:hover {
    color: var(--text);
    background: rgba(255, 255, 255, 0.03);
}

.sidebar-item.active {
    color: var(--accent);
    border-left-color: var(--accent);
    background: rgba(0, 229, 255, 0.05);
}

.item-icon {
    font-size: 0.9rem;
    width: 18px;
    text-align: center;
    flex-shrink: 0;
}

.sidebar-footer {
    position: fixed;
    bottom: 0;
    left: 0;
    width: var(--sidebar-w);
    background: var(--bg2);
    border-top: 1px solid var(--border);
    border-right: 1px solid var(--border);
    padding: 14px 16px;
    transition: width var(--transition), transform var(--transition);
}

.sidebar.collapsed + .content .sidebar-footer,
.sidebar.collapsed ~ .sidebar-footer {
    transform: translateX(-100%);
}

.progress-label {
    font-family: var(--mono);
    font-size: 0.62rem;
    letter-spacing: 1.5px;
    text-transform: uppercase;
    color: var(--text3);
    margin-bottom: 8px;
}

.progress-bar-wrap {
    height: 3px;
    background: var(--border);
    border-radius: 3px;
    overflow: hidden;
    margin-bottom: 6px;
}

.progress-bar-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--accent2), var(--accent));
    border-radius: 3px;
    transition: width 0.5s ease;
    box-shadow: 0 0 8px var(--accent);
}

.progress-pct {
    font-family: var(--mono);
    font-size: 0.7rem;
    color: var(--accent);
    text-align: right;
}

.content {
    flex: 1;
    margin-left: var(--sidebar-w);
    min-height: calc(100vh - var(--topbar-h));
    transition: margin-left var(--transition);
    padding: 40px;
    max-width: 1100px;
}

.content.sidebar-collapsed {
    margin-left: 0;
}

.section {
    display: none;
    animation: fadeUp 0.3s ease;
}

.section.active {
    display: block;
}

@keyframes fadeUp {
    from {
        opacity: 0;
        transform: translateY(10px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.section-header {
    margin-bottom: 36px;
}

.section-title {
    font-family: var(--mono);
    font-size: 1.8rem;
    font-weight: 700;
    letter-spacing: -1px;
    color: var(--text);
    margin-bottom: 6px;
}

.section-sub {
    font-family: var(--mono);
    font-size: 0.75rem;
    color: var(--text3);
    letter-spacing: 0.5px;
}


.dashboard-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 16px;
    margin-bottom: 36px;
}

.dash-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 20px;
    text-align: center;
    transition: var(--transition);
}

.dash-card:hover {
    border-color: var(--border2);
    transform: translateY(-2px);
}

.dash-card.card-accent {
    border-color: rgba(0, 229, 255, 0.25);
}

.dash-card-label {
    font-family: var(--mono);
    font-size: 0.62rem;
    letter-spacing: 2px;
    text-transform: uppercase;
    color: var(--text3);
    margin-bottom: 10px;
}

.dash-card-value {
    font-family: var(--mono);
    font-size: 2.4rem;
    font-weight: 700;
    color: var(--accent);
    line-height: 1;
}

.dash-card:not(.card-accent) .dash-card-value {
    color: var(--text);
}

.dash-card-unit {
    font-family: var(--mono);
    font-size: 0.68rem;
    color: var(--text3);
    margin-top: 4px;
}

.topic-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 16px;
    margin-bottom: 36px;
}

.topic-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 20px;
    cursor: pointer;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.topic-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 2px;
    background: linear-gradient(90deg, var(--accent2), var(--accent));
    opacity: 0;
    transition: var(--transition);
}

.topic-card:hover {
    border-color: var(--border2);
    transform: translateY(-3px);
}

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

.topic-card-icon {
    font-size: 1.4rem;
    margin-bottom: 10px;
    color: var(--accent);
}

.topic-card-name {
    font-family: var(--mono);
    font-weight: 700;
    font-size: 0.9rem;
    color: var(--text);
    margin-bottom: 6px;
}

.topic-card-desc {
    font-family: var(--mono);
    font-size: 0.7rem;
    color: var(--text3);
    margin-bottom: 14px;
}

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

.topic-progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--accent2), var(--accent));
    border-radius: 2px;
    transition: width 0.5s ease;
}

.exam-preview {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 24px;
    position: relative;
}

.exam-preview-header {
    display: flex;
    gap: 8px;
    margin-bottom: 14px;
    flex-wrap: wrap;
}

.tag {
    font-family: var(--mono);
    font-size: 0.65rem;
    letter-spacing: 1px;
    text-transform: uppercase;
    background: rgba(0, 229, 255, 0.08);
    border: 1px solid rgba(0, 229, 255, 0.2);
    color: var(--accent);
    padding: 3px 10px;
    border-radius: 3px;
}

.tag.tag-b {
    background: rgba(123, 94, 167, 0.1);
    border-color: rgba(123, 94, 167, 0.3);
    color: var(--accent2);
}

.exam-preview-text {
    font-family: var(--mono);
    font-size: 0.8rem;
    color: var(--text2);
    line-height: 1.8;
    margin-bottom: 20px;
}

.exam-preview-text strong {
    color: var(--text);
}

.cta-btn {
    background: linear-gradient(135deg, var(--accent2), var(--accent));
    color: var(--bg);
    font-family: var(--mono);
    font-size: 0.8rem;
    font-weight: 700;
    border: none;
    padding: 10px 22px;
    border-radius: var(--radius2);
    cursor: pointer;
    transition: var(--transition);
    letter-spacing: 0.5px;
}

.cta-btn:hover {
    opacity: 0.85;
    transform: translateY(-1px);
}

.materials-content {
    max-width: 860px;
}

.material-block {
    margin-bottom: 36px;
}

.material-block h2 {
    font-family: var(--mono);
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--text);
    margin-bottom: 16px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.material-block h2::after {
    content: '';
    flex: 1;
    height: 1px;
    background: var(--border);
}

.material-block h3 {
    font-family: var(--mono);
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--accent);
    margin: 20px 0 10px;
}

.material-block p {
    font-family: var(--mono);
    font-size: 0.8rem;
    color: var(--text2);
    line-height: 1.9;
    margin-bottom: 12px;
}

.material-block ul,
.material-block ol {
    padding-left: 20px;
    font-family: var(--mono);
    font-size: 0.8rem;
    color: var(--text2);
    line-height: 2;
}

.material-block code,
code {
    font-family: var(--mono);
    font-size: 0.78rem;
    background: var(--surface);
    color: var(--green);
    padding: 2px 7px;
    border-radius: 3px;
    border: 1px solid var(--border);
}

.code-block {
    background: var(--bg2);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 18px 20px;
    margin: 12px 0 20px;
    overflow-x: auto;
    position: relative;
}

.code-block::before {
    content: 'pseudokód';
    font-family: var(--mono);
    font-size: 0.6rem;
    letter-spacing: 2px;
    text-transform: uppercase;
    color: var(--text3);
    position: absolute;
    top: 8px;
    right: 12px;
}

.code-block pre {
    font-family: var(--mono);
    font-size: 0.78rem;
    color: var(--text2);
    line-height: 1.8;
    white-space: pre;
}

.code-block .kw {
    color: var(--accent);
}

.code-block .str {
    color: var(--yellow);
}

.code-block .num {
    color: var(--green);
}

.code-block .cmt {
    color: var(--text3);
    font-style: italic;
}

.code-block .fn {
    color: var(--accent2);
}

.info-box {
    background: rgba(0, 229, 255, 0.04);
    border: 1px solid rgba(0, 229, 255, 0.15);
    border-radius: var(--radius);
    padding: 14px 18px;
    margin: 12px 0;
    font-family: var(--mono);
    font-size: 0.78rem;
    color: var(--text2);
    line-height: 1.8;
}

.info-box.warn {
    background: rgba(255, 209, 102, 0.04);
    border-color: rgba(255, 209, 102, 0.2);
}

.info-box.tip {
    background: rgba(0, 255, 163, 0.04);
    border-color: rgba(0, 255, 163, 0.2);
}

.info-box-label {
    font-size: 0.62rem;
    letter-spacing: 2px;
    text-transform: uppercase;
    margin-bottom: 6px;
}

.info-box .info-box-label {
    color: var(--accent);
}

.info-box.warn .info-box-label {
    color: var(--yellow);
}

.info-box.tip .info-box-label {
    color: var(--green);
}

.material-nav {
    display: flex;
    justify-content: space-between;
    margin-top: 40px;
}

.mat-nav-btn {
    background: var(--surface);
    border: 1px solid var(--border);
    color: var(--text2);
    font-family: var(--mono);
    font-size: 0.75rem;
    padding: 9px 18px;
    border-radius: var(--radius2);
    cursor: pointer;
    transition: var(--transition);
}

.mat-nav-btn:hover {
    border-color: var(--accent);
    color: var(--accent);
}

.practice-controls {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 24px;
    flex-wrap: wrap;
    gap: 12px;
}

.practice-filter {
    display: flex;
    gap: 6px;
    flex-wrap: wrap;
}

.filter-btn {
    background: var(--surface);
    border: 1px solid var(--border);
    color: var(--text2);
    font-family: var(--mono);
    font-size: 0.7rem;
    letter-spacing: 0.5px;
    text-transform: uppercase;
    padding: 6px 14px;
    border-radius: var(--radius2);
    cursor: pointer;
    transition: var(--transition);
}

.filter-btn:hover {
    border-color: var(--border2);
    color: var(--text);
}

.filter-btn.active {
    border-color: var(--accent);
    color: var(--accent);
    background: rgba(0, 229, 255, 0.06);
}

.practice-stats-mini {
    font-family: var(--mono);
    font-size: 0.72rem;
    color: var(--text3);
}

.questions-list {
    display: flex;
    flex-direction: column;
    gap: 16px;
    max-width: 860px;
}

.question-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 20px 24px;
    transition: var(--transition);
}

.question-card.answered-correct {
    border-color: rgba(0, 255, 163, 0.3);
}

.question-card.answered-wrong {
    border-color: rgba(255, 77, 109, 0.3);
}

.q-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 12px;
    gap: 12px;
}

.q-meta {
    display: flex;
    gap: 8px;
    align-items: center;
    flex-wrap: wrap;
}

.q-tag {
    font-family: var(--mono);
    font-size: 0.6rem;
    letter-spacing: 1.5px;
    text-transform: uppercase;
    padding: 2px 8px;
    border-radius: 3px;
    border: 1px solid;
}

.q-tag.algo {
    color: var(--accent);
    border-color: rgba(0, 229, 255, 0.25);
}

.q-tag.logic {
    color: var(--accent2);
    border-color: rgba(123, 94, 167, 0.35);
}

.q-tag.binary {
    color: var(--green);
    border-color: rgba(0, 255, 163, 0.25);
}

.q-tag.hw {
    color: var(--yellow);
    border-color: rgba(255, 209, 102, 0.25);
}

.q-tag.db {
    color: var(--accent3);
    border-color: rgba(255, 77, 109, 0.25);
}

.q-points {
    font-family: var(--mono);
    font-size: 0.7rem;
    color: var(--text3);
    white-space: nowrap;
}

.q-text {
    font-family: var(--mono);
    font-size: 0.82rem;
    color: var(--text);
    line-height: 1.8;
    margin-bottom: 16px;
}

.q-options {
    display: flex;
    flex-direction: column;
    gap: 7px;
}

.q-option {
    display: flex;
    align-items: flex-start;
    gap: 10px;
    padding: 9px 14px;
    background: var(--bg2);
    border: 1px solid var(--border);
    border-radius: var(--radius2);
    cursor: pointer;
    font-family: var(--mono);
    font-size: 0.78rem;
    color: var(--text2);
    transition: var(--transition);
    text-align: left;
}

.q-option:hover {
    border-color: var(--border2);
    color: var(--text);
}

.q-option.selected {
    border-color: var(--accent);
    color: var(--accent);
    background: rgba(0, 229, 255, 0.05);
}

.q-option.correct {
    border-color: var(--green);
    color: var(--green);
    background: rgba(0, 255, 163, 0.05);
}

.q-option.wrong {
    border-color: var(--accent3);
    color: var(--accent3);
    background: rgba(255, 77, 109, 0.05);
}

.q-option:disabled,
.q-option[disabled] {
    cursor: not-allowed;
    pointer-events: none;
}

.q-option-key {
    font-weight: 700;
    flex-shrink: 0;
    width: 16px;
    text-align: center;
}

.q-open-input {
    width: 100%;
    background: var(--bg2);
    border: 1px solid var(--border);
    border-radius: var(--radius2);
    color: var(--text);
    font-family: var(--mono);
    font-size: 0.82rem;
    padding: 10px 14px;
    resize: vertical;
    min-height: 60px;
    outline: none;
    transition: var(--transition);
}

.q-open-input:focus {
    border-color: var(--accent);
}

.q-actions {
    margin-top: 14px;
    display: flex;
    gap: 10px;
    align-items: center;
}

.q-submit {
    background: rgba(0, 229, 255, 0.1);
    border: 1px solid rgba(0, 229, 255, 0.3);
    color: var(--accent);
    font-family: var(--mono);
    font-size: 0.72rem;
    padding: 7px 18px;
    border-radius: var(--radius2);
    cursor: pointer;
    transition: var(--transition);
    letter-spacing: 0.5px;
}

.q-submit:hover {
    background: rgba(0, 229, 255, 0.15);
}

.q-reveal {
    background: none;
    border: none;
    color: var(--text3);
    font-family: var(--mono);
    font-size: 0.72rem;
    cursor: pointer;
    text-decoration: underline;
    transition: var(--transition);
}

.q-reveal:hover {
    color: var(--text2);
}

.q-feedback {
    margin-top: 12px;
    font-family: var(--mono);
    font-size: 0.78rem;
    line-height: 1.7;
    display: none;
}

.q-feedback.show {
    display: block;
}

.q-feedback.correct-fb {
    color: var(--green);
}

.q-feedback.wrong-fb {
    color: var(--accent3);
}

.q-feedback .explanation {
    margin-top: 6px;
    color: var(--text2);
    font-size: 0.74rem;
}

.apps-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 20px;
    max-width: 700px;
}

.app-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 28px;
    transition: var(--transition);
    position: relative;
}

.app-card:hover {
    border-color: var(--border2);
}

.app-card-icon {
    font-family: var(--mono);
    font-size: 1.8rem;
    color: var(--accent2);
    margin-bottom: 14px;
}

.app-card-name {
    font-family: var(--mono);
    font-weight: 700;
    font-size: 1rem;
    color: var(--text);
    margin-bottom: 8px;
}

.app-card-desc {
    font-family: var(--mono);
    font-size: 0.76rem;
    color: var(--text2);
    line-height: 1.8;
    margin-bottom: 20px;
}

.app-card-status {
    display: inline-block;
    font-family: var(--mono);
    font-size: 0.6rem;
    letter-spacing: 2px;
    text-transform: uppercase;
    padding: 3px 10px;
    border-radius: 3px;
    border: 1px solid;
}

.app-card-status.coming {
    color: var(--yellow);
    border-color: rgba(255, 209, 102, 0.3);
    background: rgba(255, 209, 102, 0.05);
}

@media (max-width: 900px) {
    .dashboard-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .topic-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .content {
        padding: 24px 16px;
    }
}

@media (max-width: 650px) {
    .dashboard-grid {
        grid-template-columns: 1fr 1fr;
    }

    .topic-grid {
        grid-template-columns: 1fr;
    }

    .topbar-nav {
        display: none;
    }

    .apps-grid {
        grid-template-columns: 1fr;
    }
}

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

strong {
    color: var(--text);
    font-weight: 600;
}

.material-loading {
    font-family: var(--mono);
    font-size: 0.78rem;
    color: var(--text3);
    padding: 40px 0;
}

.lessons-overview {
    max-width: 860px;
}

.lessons-progress-row {
    display: flex;
    align-items: center;
    gap: 16px;
    margin-bottom: 28px;
}

.lessons-done-label {
    font-family: var(--mono);
    font-size: 0.7rem;
    color: var(--text3);
    white-space: nowrap;
}

.lessons-progress-bar {
    flex: 1;
    height: 3px;
    background: var(--border);
    border-radius: 3px;
    overflow: hidden;
}

.lessons-progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--accent2), var(--accent));
    border-radius: 3px;
    transition: width 0.5s ease;
    box-shadow: 0 0 8px var(--accent);
}

.lesson-cards-grid {
    display: flex;
    flex-direction: column;
    gap: 8px;
    margin-bottom: 40px;
}

.lesson-card {
    display: flex;
    align-items: center;
    gap: 16px;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 14px 20px;
    cursor: pointer;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.lesson-card::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 3px;
    background: linear-gradient(180deg, var(--accent2), var(--accent));
    opacity: 0;
    transition: var(--transition);
}

.lesson-card:hover {
    border-color: var(--border2);
    transform: translateX(4px);
}

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

.lesson-card.lesson-done {
    border-color: rgba(0, 255, 163, 0.2);
}

.lesson-card.lesson-done::before {
    opacity: 1;
    background: var(--green);
}

.lesson-card-num {
    font-family: var(--mono);
    font-size: 0.68rem;
    color: var(--text3);
    letter-spacing: 1px;
    flex-shrink: 0;
    width: 24px;
}

.lesson-card.lesson-done .lesson-card-num {
    color: var(--green);
}

.lesson-card-body {
    flex: 1;
}

.lesson-card-title {
    font-family: var(--mono);
    font-size: 0.84rem;
    font-weight: 600;
    color: var(--text);
}

.lesson-card-meta {
    font-family: var(--mono);
    font-size: 0.68rem;
    color: var(--text3);
    margin-top: 3px;
}

.lesson-card-status {
    font-family: var(--mono);
    font-size: 0.8rem;
    color: var(--text3);
    flex-shrink: 0;
    transition: var(--transition);
}

.lesson-card:hover .lesson-card-status {
    color: var(--accent);
}

.lesson-card.lesson-done .lesson-card-status {
    color: var(--green);
}

.lesson-breadcrumb {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 28px;
    font-family: var(--mono);
    font-size: 0.75rem;
}

.lesson-back-btn {
    background: none;
    border: none;
    color: var(--accent);
    cursor: pointer;
    font-family: var(--mono);
    font-size: 0.75rem;
    padding: 0;
    transition: var(--transition);
}

.lesson-back-btn:hover {
    color: var(--text);
}

.lesson-breadcrumb-sep {
    color: var(--text3);
}

.lesson-breadcrumb-cur {
    color: var(--text2);
}

.lesson-body {
    max-width: 860px;
    margin-bottom: 40px;
}

.lesson-body h1,
.lesson-body h2 {
    font-family: var(--mono);
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--text);
    margin: 32px 0 14px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.lesson-body h2::after {
    content: '';
    flex: 1;
    height: 1px;
    background: var(--border);
}

.lesson-body h3 {
    font-family: var(--mono);
    font-size: 0.88rem;
    color: var(--accent);
    margin: 22px 0 10px;
}

.lesson-body p {
    font-family: var(--mono);
    font-size: 0.8rem;
    color: var(--text2);
    line-height: 1.9;
    margin-bottom: 12px;
}

.lesson-body ul,
.lesson-body ol {
    padding-left: 20px;
    font-family: var(--mono);
    font-size: 0.8rem;
    color: var(--text2);
    line-height: 2;
}

.lesson-body pre {
    background: var(--bg2);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 18px 20px;
    margin: 12px 0 20px;
    overflow-x: auto;
    font-family: var(--mono);
    font-size: 0.78rem;
    color: var(--text2);
    line-height: 1.8;
}

.lesson-body code {
    font-family: var(--mono);
    font-size: 0.78rem;
    background: var(--surface);
    color: var(--green);
    padding: 2px 7px;
    border-radius: 3px;
    border: 1px solid var(--border);
}

.lesson-body pre code {
    background: none;
    border: none;
    padding: 0;
    color: var(--text2);
}

.lesson-body table {
    width: 100%;
    border-collapse: collapse;
    font-family: var(--mono);
    font-size: 0.78rem;
    margin: 16px 0;
}

.lesson-body th {
    background: var(--surface);
    color: var(--accent);
    border: 1px solid var(--border);
    padding: 8px 12px;
    text-align: left;
}

.lesson-body td {
    border: 1px solid var(--border);
    padding: 8px 12px;
    color: var(--text2);
}

.lesson-body tr:hover td {
    background: rgba(255, 255, 255, 0.02);
}

.lesson-body blockquote {
    border-left: 3px solid var(--accent2);
    margin: 12px 0;
    padding: 10px 16px;
    background: rgba(123, 94, 167, 0.06);
    font-family: var(--mono);
    font-size: 0.78rem;
    color: var(--text2);
}

.lesson-nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 12px;
    padding-top: 24px;
    border-top: 1px solid var(--border);
    margin-top: 8px;
}

.lesson-done-btn {
    background: rgba(0, 229, 255, 0.07);
    border: 1px solid rgba(0, 229, 255, 0.25);
    color: var(--accent);
    font-family: var(--mono);
    font-size: 0.72rem;
    padding: 8px 20px;
    border-radius: var(--radius2);
    cursor: pointer;
    transition: var(--transition);
    letter-spacing: 0.5px;
}

.lesson-done-btn:hover {
    background: rgba(0, 229, 255, 0.14);
}

.lesson-done-btn.done {
    background: rgba(0, 255, 163, 0.07);
    border-color: rgba(0, 255, 163, 0.3);
    color: var(--green);
    cursor: default;
}


.topic-quiz-container {
    max-width: 860px;
    margin-bottom: 40px;
}

.quiz-block {
    border: 1px solid var(--border);
    border-radius: var(--radius);
    overflow: hidden;
}

.quiz-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 12px 20px;
    background: var(--surface);
    border-bottom: 1px solid var(--border);
}

.quiz-header-left {
    display: flex;
    align-items: center;
    gap: 12px;
}

.quiz-label {
    font-family: var(--mono);
    font-size: 0.62rem;
    letter-spacing: 2px;
    text-transform: uppercase;
    color: var(--accent2);
}

.quiz-count {
    font-family: var(--mono);
    font-size: 0.7rem;
    color: var(--text3);
}

.quiz-prev-score {
    font-family: var(--mono);
    font-size: 0.7rem;
    color: var(--text3);
}

.quiz-prev-score strong {
    color: var(--text);
}

.quiz-body {
    padding: 24px;
}

.quiz-start-desc {
    font-family: var(--mono);
    font-size: 0.8rem;
    color: var(--text2);
    margin-bottom: 20px;
    line-height: 1.8;
}

.quiz-start-btn,
.quiz-retry-btn {
    background: rgba(123, 94, 167, 0.12);
    border: 1px solid rgba(123, 94, 167, 0.35);
    color: var(--accent2);
    font-family: var(--mono);
    font-size: 0.75rem;
    padding: 9px 22px;
    border-radius: var(--radius2);
    cursor: pointer;
    transition: var(--transition);
}

.quiz-start-btn:hover,
.quiz-retry-btn:hover {
    background: rgba(123, 94, 167, 0.2);
}

.quiz-question {
    margin-bottom: 28px;
    padding-bottom: 28px;
    border-bottom: 1px solid var(--border);
}

.quiz-question:last-of-type {
    border-bottom: none;
    margin-bottom: 0;
}

.quiz-q-num {
    font-family: var(--mono);
    font-size: 0.62rem;
    letter-spacing: 2px;
    text-transform: uppercase;
    color: var(--text3);
    margin-bottom: 8px;
}

.quiz-q-text {
    font-family: var(--mono);
    font-size: 0.84rem;
    color: var(--text);
    line-height: 1.7;
    margin-bottom: 14px;
    white-space: pre-line;
}

.quiz-explanation {
    margin-top: 10px;
    padding: 10px 14px;
    background: rgba(0, 229, 255, 0.04);
    border: 1px solid rgba(0, 229, 255, 0.12);
    border-radius: var(--radius2);
    font-family: var(--mono);
    font-size: 0.74rem;
    color: var(--text2);
    line-height: 1.7;
}

.quiz-submit-row {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: 24px;
    padding-top: 20px;
    border-top: 1px solid var(--border);
}

.quiz-answered-count {
    font-family: var(--mono);
    font-size: 0.72rem;
    color: var(--text3);
}

.quiz-submit-btn {
    background: rgba(0, 229, 255, 0.1);
    border: 1px solid rgba(0, 229, 255, 0.3);
    color: var(--accent);
    font-family: var(--mono);
    font-size: 0.75rem;
    padding: 8px 22px;
    border-radius: var(--radius2);
    cursor: pointer;
    transition: var(--transition);
}

.quiz-submit-btn:disabled {
    opacity: 0.35;
    cursor: not-allowed;
}

.quiz-submit-btn:not(:disabled):hover {
    background: rgba(0, 229, 255, 0.18);
}

.quiz-results {
    display: flex;
    flex-direction: column;
    gap: 20px;
    align-items: flex-start;
}

.quiz-score {
    display: flex;
    align-items: baseline;
    gap: 14px;
    padding: 18px 24px;
    border-radius: var(--radius);
    border: 1px solid;
    width: 100%;
}

.quiz-score-excellent {
    border-color: rgba(0, 255, 163, 0.3);
    background: rgba(0, 255, 163, 0.05);
}

.quiz-score-ok {
    border-color: rgba(255, 209, 102, 0.3);
    background: rgba(255, 209, 102, 0.05);
}

.quiz-score-poor {
    border-color: rgba(255, 77, 109, 0.3);
    background: rgba(255, 77, 109, 0.05);
}

.quiz-score-emoji {
    font-size: 1.4rem;
}

.quiz-score-num {
    font-family: var(--mono);
    font-size: 1.6rem;
    font-weight: 700;
    color: var(--text);
}

.quiz-score-pct {
    font-family: var(--mono);
    font-size: 0.9rem;
    color: var(--text2);
}

.quiz-breakdown {
    width: 100%;
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.quiz-result-row {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 8px 14px;
    border-radius: var(--radius2);
    font-family: var(--mono);
    font-size: 0.76rem;
}

.quiz-result-row.correct {
    background: rgba(0, 255, 163, 0.05);
    color: var(--text2);
}

.quiz-result-row.wrong {
    background: rgba(255, 77, 109, 0.05);
    color: var(--text3);
}

.qrr-num {
    color: var(--text3);
    flex-shrink: 0;
    width: 20px;
}

.qrr-text {
    flex: 1;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.qrr-icon {
    flex-shrink: 0;
}

.quiz-result-row.correct .qrr-icon {
    color: var(--green);
}

.quiz-result-row.wrong .qrr-icon {
    color: var(--accent3);
}

.qrr-pts {
    flex-shrink: 0;
    font-weight: 700;
}

.quiz-result-row.correct .qrr-pts {
    color: var(--green);
}

.quiz-result-row.wrong .qrr-pts {
    color: var(--text3);
}

.exam-lobby {
    max-width: 640px;
}

.exam-lobby-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 12px;
    margin-bottom: 24px;
}

.exam-stat-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 18px;
    text-align: center;
}

.exam-stat-val {
    font-family: var(--mono);
    font-size: 2rem;
    font-weight: 700;
    color: var(--accent);
    line-height: 1;
}

.exam-stat-label {
    font-family: var(--mono);
    font-size: 0.62rem;
    color: var(--text3);
    letter-spacing: 1px;
    text-transform: uppercase;
    margin-top: 6px;
}

.exam-lobby-info {
    margin-bottom: 24px;
}

.exam-start-btn {
    background: linear-gradient(135deg, var(--accent2), var(--accent));
    color: var(--bg);
    font-family: var(--mono);
    font-size: 0.82rem;
    font-weight: 700;
    border: none;
    padding: 12px 28px;
    border-radius: var(--radius2);
    cursor: pointer;
    transition: var(--transition);
    letter-spacing: 0.5px;
}

.exam-start-btn:hover {
    opacity: 0.85;
    transform: translateY(-1px);
}

.exam-running {
    max-width: 860px;
}

.exam-topbar {
    position: sticky;
    top: var(--topbar-h);
    z-index: 50;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
    background: var(--bg2);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 12px 20px;
    margin-bottom: 28px;
    backdrop-filter: blur(12px);
}

.exam-timer {
    font-family: var(--mono);
    font-size: 1.4rem;
    font-weight: 700;
    color: var(--accent);
    letter-spacing: 2px;
}

.exam-timer.timer-warn {
    color: var(--accent3);
    animation: pulse-dot 1s ease-in-out infinite;
}

.exam-progress-info {
    font-family: var(--mono);
    font-size: 0.75rem;
    color: var(--text3);
}

.exam-submit-early-btn {
    background: rgba(0, 229, 255, 0.1);
    border: 1px solid rgba(0, 229, 255, 0.3);
    color: var(--accent);
    font-family: var(--mono);
    font-size: 0.72rem;
    padding: 7px 18px;
    border-radius: var(--radius2);
    cursor: pointer;
    transition: var(--transition);
}

.exam-submit-early-btn:hover {
    background: rgba(0, 229, 255, 0.18);
}

.exam-questions-wrap {
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.exam-question {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 20px 24px;
}

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

.exam-q-points {
    font-family: var(--mono);
    font-size: 0.68rem;
    color: var(--text3);
    margin-left: auto;
}

.exam-results {
    max-width: 860px;
}

.exam-time-up-banner {
    background: rgba(255, 77, 109, 0.08);
    border: 1px solid rgba(255, 77, 109, 0.25);
    border-radius: var(--radius);
    padding: 10px 20px;
    font-family: var(--mono);
    font-size: 0.8rem;
    color: var(--accent3);
    margin-bottom: 20px;
}

.exam-verdict {
    font-family: var(--mono);
    font-size: 1rem;
    font-weight: 700;
    letter-spacing: 3px;
    padding: 12px 20px;
    border-radius: var(--radius2);
}

.exam-verdict.pass {
    color: var(--green);
    background: rgba(0, 255, 163, 0.07);
    border: 1px solid rgba(0, 255, 163, 0.25);
}

.exam-verdict.fail {
    color: var(--accent3);
    background: rgba(255, 77, 109, 0.07);
    border: 1px solid rgba(255, 77, 109, 0.25);
}