/* ====================================================
   Python Course Styles — KidsLearn
   Accent palette: Python blue (#306998) + yellow (#FFD43B)
   ==================================================== */

:root {
    --py-blue: #306998;
    --py-blue-dark: #1f4d73;
    --py-yellow: #ffd43b;
    --py-yellow-dark: #f2b705;
}

/* ---- Landing: progress / course path ---- */
.course-intro {
    background: linear-gradient(135deg, rgba(48, 105, 152, 0.12) 0%, rgba(255, 212, 59, 0.18) 100%);
    border-left: 6px solid var(--py-blue);
    padding: 24px 28px;
    border-radius: 12px;
    margin-bottom: 30px;
}

.course-intro h2 {
    color: var(--py-blue);
    margin-bottom: 10px;
}

.course-intro p {
    color: #374151;
    line-height: 1.7;
    margin-bottom: 8px;
}

/* Numbered lesson cards on the landing page */
.lesson-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 22px;
    margin-bottom: 30px;
}

.lesson-card {
    position: relative;
    background: linear-gradient(135deg, #ffffff 0%, #f5f9ff 100%);
    border: 3px solid #e2e8f0;
    border-radius: 16px;
    padding: 24px 24px 24px 70px;
    transition: all 0.25s ease;
    text-decoration: none;
    display: block;
    color: inherit;
}

.lesson-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 12px 26px rgba(48, 105, 152, 0.25);
    border-color: var(--py-blue);
}

.lesson-number {
    position: absolute;
    left: 18px;
    top: 22px;
    width: 40px;
    height: 40px;
    background: linear-gradient(135deg, var(--py-blue) 0%, var(--py-blue-dark) 100%);
    color: #fff;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 800;
    font-size: 1.15em;
    box-shadow: 0 3px 8px rgba(48, 105, 152, 0.4);
}

.lesson-card h3 {
    color: #1f2937;
    font-size: 1.25em;
    margin-bottom: 6px;
}

.lesson-card p {
    color: #6b7280;
    font-size: 0.98em;
    line-height: 1.5;
    margin: 0;
}

.lesson-card .lesson-tag {
    display: inline-block;
    margin-top: 12px;
    font-size: 0.8em;
    font-weight: 700;
    color: var(--py-blue-dark);
    background: var(--py-yellow);
    padding: 3px 12px;
    border-radius: 20px;
}

/* ---- Lesson page: tabs ---- */
.lesson-tabs {
    display: flex;
    gap: 10px;
    justify-content: center;
    flex-wrap: wrap;
    margin: 20px 0 30px;
}

.lesson-tab {
    padding: 12px 30px;
    border: 2px solid #d7def0;
    border-radius: 30px;
    background: white;
    cursor: pointer;
    font-size: 1.05em;
    font-weight: 700;
    color: var(--py-blue);
    transition: all 0.25s;
    font-family: inherit;
}

.lesson-tab:hover {
    background: #f0f5ff;
    border-color: var(--py-blue);
}

.lesson-tab.active {
    background: linear-gradient(135deg, var(--py-blue) 0%, var(--py-blue-dark) 100%);
    color: white;
    border-color: var(--py-blue);
}

.tab-panel {
    max-width: 920px;
    margin: 0 auto;
}

/* ---- Description content ---- */
.lesson-section h2 {
    border-bottom-color: var(--py-blue);
}

.info-box {
    background: linear-gradient(135deg, rgba(48, 105, 152, 0.1) 0%, rgba(255, 212, 59, 0.12) 100%);
    border-left-color: var(--py-blue);
}

.example-box h3 {
    color: var(--py-blue);
}

.tip-box {
    background: linear-gradient(135deg, rgba(255, 212, 59, 0.18) 0%, rgba(242, 183, 5, 0.12) 100%);
    border-left-color: var(--py-yellow-dark);
}

.tip-box h4 {
    color: #b45309;
}

.warn-box {
    background: linear-gradient(135deg, rgba(239, 68, 68, 0.08) 0%, rgba(248, 113, 113, 0.08) 100%);
    border-left: 5px solid #ef4444;
    padding: 20px;
    border-radius: 8px;
    margin: 20px 0;
}

.warn-box h4 {
    color: #dc2626;
    margin-bottom: 10px;
}

.warn-box p, .warn-box li {
    color: #374151;
}

/* Code block shown inside descriptions */
.code-block {
    background: #1e293b;
    color: #e2e8f0;
    padding: 18px 20px;
    border-radius: 10px;
    font-family: 'Menlo', 'Consolas', 'Courier New', monospace;
    font-size: 0.98em;
    line-height: 1.6;
    overflow-x: auto;
    margin: 16px 0;
    white-space: pre;
    tab-size: 4;
}

.code-block .cmt { color: #94a3b8; font-style: italic; }
.code-block .kw  { color: #f472b6; font-weight: bold; }
.code-block .str { color: #fcd34d; }
.code-block .num { color: #7dd3fc; }
.code-block .fn  { color: #86efac; }
.code-block .out { color: #94a3b8; }

/* Inline code */
.lesson-section code, .task-goal code, p code, li code {
    background: #eef2ff;
    color: #4338ca;
    padding: 2px 7px;
    border-radius: 5px;
    font-family: 'Menlo', 'Consolas', monospace;
    font-size: 0.92em;
}

/* ---- Practice tasks ---- */
.practice-intro {
    text-align: center;
    background: linear-gradient(135deg, rgba(48, 105, 152, 0.1) 0%, rgba(255, 212, 59, 0.15) 100%);
    border-radius: 14px;
    padding: 22px;
    margin-bottom: 26px;
}

.practice-intro h2 {
    color: var(--py-blue);
    margin-bottom: 8px;
}

.practice-intro p {
    color: #4b5563;
    margin: 0;
}

.task {
    background: white;
    border: 2px solid #e2e8f0;
    border-radius: 16px;
    padding: 24px;
    margin-bottom: 28px;
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.06);
    transition: border-color 0.3s;
}

.task.task-done {
    border-color: #22c55e;
    box-shadow: 0 0 0 3px rgba(34, 197, 94, 0.18);
}

.task-head {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 10px;
}

.task-badge {
    flex-shrink: 0;
    width: 42px;
    height: 42px;
    background: linear-gradient(135deg, var(--py-yellow) 0%, var(--py-yellow-dark) 100%);
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.3em;
}

.task-head h3 {
    color: #1f2937;
    font-size: 1.25em;
    margin: 0;
}

.task-difficulty {
    margin-left: auto;
    font-size: 0.8em;
    font-weight: 700;
    padding: 4px 12px;
    border-radius: 20px;
    white-space: nowrap;
}

.diff-easy   { background: #dcfce7; color: #166534; }
.diff-medium { background: #fef9c3; color: #854d0e; }
.diff-hard   { background: #fee2e2; color: #991b1b; }

.task-goal {
    color: #4b5563;
    line-height: 1.7;
    margin-bottom: 16px;
    font-size: 1.05em;
}

.task-goal ul {
    margin: 8px 0 0 22px;
}

.task-goal li {
    margin: 4px 0;
}

/* ---- Playground / editor ---- */
.playground {
    border: 2px solid #d7def0;
    border-radius: 12px;
    overflow: hidden;
    background: #1e293b;
}

.code-input {
    width: 100%;
    min-height: 150px;
    border: none;
    outline: none;
    resize: vertical;
    background: #1e293b;
    color: #f1f5f9;
    font-family: 'Menlo', 'Consolas', 'Courier New', monospace;
    font-size: 0.98em;
    line-height: 1.6;
    padding: 16px 18px;
    tab-size: 4;
    display: block;
}

.pg-buttons {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
    padding: 10px 12px;
    background: #0f172a;
    border-top: 1px solid #334155;
}

.pg-buttons button {
    font-family: inherit;
    font-weight: 700;
    font-size: 0.92em;
    padding: 9px 18px;
    border-radius: 8px;
    border: none;
    cursor: pointer;
    transition: all 0.2s;
}

.run-btn {
    background: linear-gradient(135deg, #22c55e 0%, #16a34a 100%);
    color: white;
}

.run-btn:hover:not(:disabled) { filter: brightness(1.08); transform: translateY(-1px); }
.run-btn:disabled { opacity: 0.7; cursor: progress; }

.check-btn {
    background: linear-gradient(135deg, var(--py-yellow) 0%, var(--py-yellow-dark) 100%);
    color: #1f2937;
}

.check-btn:hover { filter: brightness(1.05); transform: translateY(-1px); }

.reset-btn, .solution-btn {
    background: #334155;
    color: #e2e8f0;
}

.reset-btn:hover, .solution-btn:hover { background: #475569; }

.pg-output {
    margin: 0;
    padding: 16px 18px;
    background: #111827;
    color: #d1fae5;
    font-family: 'Menlo', 'Consolas', 'Courier New', monospace;
    font-size: 0.95em;
    line-height: 1.55;
    white-space: pre-wrap;
    word-break: break-word;
    min-height: 30px;
    max-height: 320px;
    overflow-y: auto;
    border-top: 1px solid #334155;
}

.pg-output.error { color: #fca5a5; }
.pg-output.success { color: #86efac; }
.pg-output:empty::before {
    content: 'Output will appear here when you press ▶ Run';
    color: #64748b;
    font-style: italic;
}

.solution {
    margin-top: 14px;
    border: 2px dashed #cbd5e1;
    border-radius: 10px;
    padding: 6px 16px;
    background: #f8fafc;
}

.solution pre {
    font-family: 'Menlo', 'Consolas', monospace;
    font-size: 0.95em;
    line-height: 1.6;
    white-space: pre-wrap;
    color: #1e293b;
}

/* Lesson navigation (prev / next) */
.lesson-nav {
    display: flex;
    justify-content: space-between;
    gap: 12px;
    max-width: 920px;
    margin: 36px auto 0;
    flex-wrap: wrap;
}

.lesson-nav a {
    flex: 1;
    min-width: 160px;
    text-decoration: none;
    background: linear-gradient(135deg, var(--py-blue) 0%, var(--py-blue-dark) 100%);
    color: white;
    padding: 14px 20px;
    border-radius: 12px;
    font-weight: 700;
    transition: all 0.25s;
    text-align: center;
}

.lesson-nav a:hover { filter: brightness(1.1); transform: translateY(-2px); }
.lesson-nav a.nav-prev { background: linear-gradient(135deg, #64748b 0%, #475569 100%); }
.lesson-nav a.disabled { opacity: 0.4; pointer-events: none; }

@media (max-width: 600px) {
    .lesson-tab { padding: 10px 20px; font-size: 0.95em; }
    .lesson-card { padding-left: 64px; }
}

/* ====================================================
   Hub: course track cards
   ==================================================== */
.track-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 24px;
    margin-bottom: 28px;
}

.track-card {
    display: block;
    text-decoration: none;
    color: inherit;
    background: #ffffff;
    border: 3px solid #e2e8f0;
    border-radius: 18px;
    padding: 26px;
    transition: all 0.25s ease;
    border-top-width: 7px;
}

.track-card:hover {
    transform: translateY(-6px);
    box-shadow: 0 14px 30px rgba(0, 0, 0, 0.18);
}

.track-basics { border-top-color: var(--py-yellow-dark); }
.track-basics:hover { border-color: var(--py-yellow-dark); }
.track-algo   { border-top-color: #7c3aed; }
.track-algo:hover { border-color: #7c3aed; }
.track-arch   { border-top-color: #0d9488; }
.track-arch:hover { border-color: #0d9488; }

.track-top {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 12px;
}

.track-icon { font-size: 2.6em; }

.track-level {
    font-size: 0.75em;
    font-weight: 800;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    padding: 5px 12px;
    border-radius: 20px;
    background: #f1f5f9;
    color: #475569;
}

.track-basics .track-level { background: #fef3c7; color: #92400e; }
.track-algo .track-level   { background: #ede9fe; color: #5b21b6; }
.track-arch .track-level   { background: #ccfbf1; color: #115e59; }

.track-card h2 {
    color: #1f2937;
    font-size: 1.4em;
    margin-bottom: 10px;
}

.track-card > p {
    color: #6b7280;
    line-height: 1.6;
    margin-bottom: 14px;
}

.track-topics {
    list-style: none;
    padding: 0;
    margin: 0 0 18px;
}

.track-topics li {
    color: #475569;
    font-size: 0.92em;
    padding: 5px 0 5px 24px;
    position: relative;
}

.track-topics li::before {
    content: '✓';
    position: absolute;
    left: 0;
    color: #22c55e;
    font-weight: 800;
}

.track-cta {
    display: inline-block;
    font-weight: 800;
    color: #fff;
    padding: 10px 22px;
    border-radius: 30px;
    background: linear-gradient(135deg, var(--py-blue) 0%, var(--py-blue-dark) 100%);
}

.track-algo .track-cta { background: linear-gradient(135deg, #7c3aed 0%, #6d28d9 100%); }
.track-arch .track-cta { background: linear-gradient(135deg, #0d9488 0%, #0f766e 100%); }

.path-note {
    background: #f8fafc;
    border: 2px dashed #cbd5e1;
    border-radius: 12px;
    padding: 16px 22px;
    margin-bottom: 24px;
}

.path-note p { margin: 0; color: #475569; }
.path-note a { color: var(--py-blue); font-weight: 700; }

/* ====================================================
   Advanced course accent themes
   Apply .theme-algo or .theme-arch on <body>
   ==================================================== */
.theme-algo .lesson-tab { color: #7c3aed; border-color: #ddd6fe; }
.theme-algo .lesson-tab:hover { background: #f5f3ff; border-color: #7c3aed; }
.theme-algo .lesson-tab.active {
    background: linear-gradient(135deg, #7c3aed 0%, #6d28d9 100%);
    border-color: #7c3aed;
}
.theme-algo .lesson-section h2 { border-bottom-color: #7c3aed; }
.theme-algo h1 { color: #6d28d9; }
.theme-algo .info-box { background: linear-gradient(135deg, rgba(124,58,237,0.1) 0%, rgba(167,139,250,0.12) 100%); border-left-color: #7c3aed; }
.theme-algo .example-box h3 { color: #6d28d9; }
.theme-algo .lesson-number { background: linear-gradient(135deg, #7c3aed 0%, #6d28d9 100%); box-shadow: 0 3px 8px rgba(124,58,237,0.4); }
.theme-algo .lesson-card:hover { border-color: #7c3aed; box-shadow: 0 12px 26px rgba(124,58,237,0.25); }
.theme-algo .lesson-card .lesson-tag { background: #ddd6fe; color: #5b21b6; }
.theme-algo .lesson-nav a { background: linear-gradient(135deg, #7c3aed 0%, #6d28d9 100%); }
.theme-algo .lesson-nav a.nav-prev { background: linear-gradient(135deg, #64748b 0%, #475569 100%); }
.theme-algo .check-btn { background: linear-gradient(135deg, #a78bfa 0%, #7c3aed 100%); color: #fff; }
.theme-algo .task-badge { background: linear-gradient(135deg, #a78bfa 0%, #7c3aed 100%); }
.theme-algo .practice-intro, .theme-algo .course-intro { background: linear-gradient(135deg, rgba(124,58,237,0.1) 0%, rgba(167,139,250,0.14) 100%); }
.theme-algo .practice-intro h2, .theme-algo .course-intro h2 { color: #6d28d9; }

.theme-arch .lesson-tab { color: #0d9488; border-color: #99f6e4; }
.theme-arch .lesson-tab:hover { background: #f0fdfa; border-color: #0d9488; }
.theme-arch .lesson-tab.active {
    background: linear-gradient(135deg, #0d9488 0%, #0f766e 100%);
    border-color: #0d9488;
}
.theme-arch .lesson-section h2 { border-bottom-color: #0d9488; }
.theme-arch h1 { color: #0f766e; }
.theme-arch .info-box { background: linear-gradient(135deg, rgba(13,148,136,0.1) 0%, rgba(45,212,191,0.12) 100%); border-left-color: #0d9488; }
.theme-arch .example-box h3 { color: #0f766e; }
.theme-arch .lesson-number { background: linear-gradient(135deg, #0d9488 0%, #0f766e 100%); box-shadow: 0 3px 8px rgba(13,148,136,0.4); }
.theme-arch .lesson-card:hover { border-color: #0d9488; box-shadow: 0 12px 26px rgba(13,148,136,0.25); }
.theme-arch .lesson-card .lesson-tag { background: #ccfbf1; color: #115e59; }
.theme-arch .lesson-nav a { background: linear-gradient(135deg, #0d9488 0%, #0f766e 100%); }
.theme-arch .lesson-nav a.nav-prev { background: linear-gradient(135deg, #64748b 0%, #475569 100%); }
.theme-arch .check-btn { background: linear-gradient(135deg, #2dd4bf 0%, #0d9488 100%); color: #fff; }
.theme-arch .task-badge { background: linear-gradient(135deg, #2dd4bf 0%, #0d9488 100%); }
.theme-arch .practice-intro, .theme-arch .course-intro { background: linear-gradient(135deg, rgba(13,148,136,0.1) 0%, rgba(45,212,191,0.14) 100%); }
.theme-arch .practice-intro h2, .theme-arch .course-intro h2 { color: #0f766e; }

/* ---- Complexity / comparison tables for algorithm lessons ---- */
.algo-table-wrap { overflow-x: auto; margin: 18px 0; }
table.algo-table {
    border-collapse: collapse;
    width: 100%;
    min-width: 360px;
    background: #fff;
    border-radius: 10px;
    overflow: hidden;
    box-shadow: 0 2px 8px rgba(0,0,0,0.08);
    font-size: 0.96em;
}
table.algo-table th {
    background: #7c3aed;
    color: #fff;
    padding: 10px 14px;
    text-align: left;
}
.theme-arch table.algo-table th { background: #0d9488; }
table.algo-table td {
    padding: 9px 14px;
    border-bottom: 1px solid #e5e7eb;
    color: #374151;
}
table.algo-table tr:nth-child(even) td { background: #faf9ff; }
.theme-arch table.algo-table tr:nth-child(even) td { background: #f0fdfa; }
table.algo-table tr:last-child td { border-bottom: none; }

.big-o {
    display: inline-block;
    font-family: 'Menlo', 'Consolas', monospace;
    font-weight: 700;
    padding: 2px 8px;
    border-radius: 5px;
    background: #f1f5f9;
}
.o-good { background: #dcfce7; color: #166534; }
.o-ok   { background: #fef9c3; color: #854d0e; }
.o-bad  { background: #fee2e2; color: #991b1b; }