.logout-form { display: inline; }
.logout-form .btn-link { padding: 0 0 0 8px; vertical-align: baseline; }
img { max-width: 100%; height: auto; }
.auth-form { max-width: 520px; margin: 25px auto; }
.auth-form input { width: 100%; padding: 8px; border: 1px solid #aaa; border-radius: 4px; }
.auth-form .helptext { display: block; color: #555; font-size: 90%; }
.errorlist { color: #a94442; padding-left: 20px; }
.submission-status { margin: 12px 0; }
.table-responsive { border: 0; }
@media (max-width: 767px) {
    .sidebar { display: block; position: static; max-height: 220px; overflow-y: auto; background: #f5f5f5; margin-top: 12px; }
    .main { padding-top: 15px; }
    .visualizer > .row > [class*="col-xs-"] { width: 100%; }
    .visualizer_code_toppanel { height: auto; min-height: 36px; }
    .visualizer_explain_mode { display: inline-block; }
    .visualizer_vcr { height: auto; min-height: 40px; }
    .visualizer_dataviz { overflow-x: auto; }
    .titlePane h1 { font-size: 28px; }
}

.auth-form select, .auth-form textarea { width: 100%; padding: 8px; }

/* Measured from pythontutor.ru/old/ on 2026-09-27. */
@font-face { font-family: 'Rubik One'; src: url('../vendor/original/rubik-one-cyrillic.woff2') format('woff2'); font-weight: 400; font-display: swap; }
body { font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif; font-size: 16px; line-height: 1.5; color: #373a3c; background: white; }
h1,h2,h3,h4 { font-family: inherit; font-weight: 500; line-height: 1.1; margin: 0 0 8px; }
h1 { font-size: 40px; } h2 { font-size: 32px; } h3 { font-size: 28px; } h4 { font-size: 24px; }
p { margin: 0 0 16px; }
a { color: #0275d8; } a:hover,a:focus { color: #014c8c; }
.navbar { background: #f7f7f9; border: 0; min-height: 38px; margin-bottom: 0; border-radius: 0; }
.navbar-brand { font-family: 'Rubik One', sans-serif; text-transform: uppercase; font-size: 20px; font-weight: 400; color: #333 !important; height: 38px; line-height: 30px; padding: 4px 0; margin-right: 16px; }
.navbar-default .navbar-nav > li > a { color: rgba(0,0,0,.5); padding: 7px 8px; line-height: 24px; }
.navbar-default .navbar-nav > li > a:hover { color: #333; }
.navbar-default .navbar-nav > .active > a { background: transparent; color: #333; }
.navbar-text { margin-top: 7px; margin-bottom: 7px; line-height: 24px; }
.logout-form .btn-link { font-size: inherit; color: #0275d8; padding-left: 4px; }
.navbar-toggle { margin-top: 3px; margin-bottom: 3px; }
footer { padding: 11px 0 40px 20px; margin-top: 32px; }
.home-title { text-align: center; padding: 32px 17px; margin: 0 -15px; }
.home-lessons { margin-top: 32px; }
.home-features ul { margin-top: 30px; margin-bottom: 16px; padding-left: 40px; }
.home-features { overflow: hidden; }
.home-features video { display: block; width: 600px; max-width: none; height: auto; }
.home-demo { margin-top: 56px; }
.home-demo > h3 { margin-bottom: 32px; }
.additional-lessons { margin-top: 16px; font-size: 14px; }
.additional-lessons summary { color: #0275d8; cursor: pointer; margin-bottom: 16px; }
.page-header { margin: 20px 0 32px; padding: 0; border: 0; font-size: 28px; }
.page-header small { font-size: inherit; color: inherit; }
.section h2 { font-size: 28px; margin-top: 24px; }
.sidebar { font-size: 13px; }
.sidebar .nav-sidebar > li > a { padding: 10px 15px; }
@media (min-width:768px) {
 .navbar > .container { width: calc(100% - 64px); max-width: 1140px; padding: 0 15px; display: flex; align-items: flex-start; }
 .navbar > .container:before,.navbar > .container:after { display:none; }
 .navbar > .container .navbar-brand { margin-left: 0; }
 .navbar-collapse { flex: 1; padding: 0; display: flex !important; align-items: flex-start; }
 .navbar-collapse:before,.navbar-collapse:after { display:none; }
 .navbar-text.navbar-right { margin-left: auto; margin-right: 0; white-space: nowrap; }
 .navbar-nav { display: flex; flex-wrap: wrap; }
 .sidebar { top: 38px; background: white; border-right: 0; padding-top: 10px; }
 body:has(.sidebar) { padding-top: 48px; }
 .main { padding: 0 30px 20px 15px; }
}
@media (max-width:767px) {
 .navbar-brand { margin-left: 15px; }
 .navbar-text { margin-left: 15px; }
 .home-title { padding: 26px 15px; }
 .home-title h2 { font-size: 28px; }
 .home-title h3 { font-size: 22px; }
 .home-features { margin-top: 24px; }
 .home-features video { max-width: 100%; }
 .home-demo { margin-top: 32px; }
 body:has(.sidebar) { padding-top: 48px; }
}

.section > h2 a, .section > h3 a { color: inherit; }
.section > h2 small, .section > h3 small { color: inherit; font-size: inherit; }
.lesson_name { font-size: 28px; margin: 20px 0 24px; }
.problem_name { font-size: 28px; }
@media (min-width: 992px) { .main { max-width: 900px; } }

/* Shared controls measured against the original Bootstrap 4-era interface. */
.btn { font-size: 16px; line-height: 1.25; padding: 8px 16px; border-radius: 4px; }
.btn-primary { background: #0275d8; border-color: #0275d8; }
.btn-primary:hover,.btn-primary:focus { background: #025aa5; border-color: #01549b; }
.btn-lg { font-size: 20px; padding: 12px 24px; }
.btn-sm { font-size: 14px; padding: 4px 8px; }
.visualizer_code_toppanel button { margin-right: 16px; }
.visualizer_code_bottompanel button { font-size: 13px; }
.sidebar-toggle { padding: 2px 10px; margin: 0 10px 5px 0; font-size: 16px; vertical-align: middle; }
.lesson-menu-hidden .sidebar { display: none; }
.lesson-menu-hidden .main { margin-left: 0; width: 100%; }
.lesson_name { margin-top: 0; margin-bottom: 10px; }
.problem_name { margin-top: 10px; }
.statement-title { font-size: 20px; }
.input-hint { font-size: 13px; color: #777; }
hr { margin-top: 16px; margin-bottom: 16px; }
.auth-title { margin: 32px 0 24px; }
.login-form { width: 300px; max-width: 100%; margin: 0 auto 16px; }
.login-form input { border-color: #ddd; border-radius: 0; height: 42px; font-size: 14px; }
.login-form input:first-of-type { border-radius: 4px 4px 0 0; }
.login-form input:last-of-type { border-top: 0; border-radius: 0 0 4px 4px; }
.register-form { max-width: none; margin: 0 0 32px; }
.register-row { display: grid; grid-template-columns: 33.333% 41.667%; gap: 0 15px; margin-bottom: 16px; }
.register-row label { font-weight: 400; padding-top: 6px; }
.register-row input { border-color: #ddd; padding: 8px 12px; }
@media (min-width:768px) {
 .sidebar { position: static; padding: 0 52px 0 15px; margin-bottom: 100px; overflow: visible; }
 .sidebar .nav-sidebar { margin-left: -20px; margin-right: -21px; }
 .sidebar .nav-sidebar > li > a { padding: 10px 20px; }
 .sidebar .nav-sidebar > .active > a { color: #0275d8; background: transparent; }
 .sidebar .lesson_sections { background: #e3ebf1; }
 .main { padding: 0 15px 20px; margin-left: 0; width: 75%; max-width: 900px; }
 .page-header { margin-top: 0; }
}
@media (min-width:1200px) { .main { width: 58.333333%; } }
@media (max-width:767px) { .register-row { display: block; } .main { width: 100%; margin-left: 0; } }

/* Match the original top navigation and plain-text visualizer controls. */
.navbar-default .navbar-nav > li > a { padding-left: 0; padding-right: 0; margin-left: 16px; }
.navbar-default .navbar-nav > li:first-child > a { margin-left: 0; }
.navbar-default .navbar-nav .original-en { color: red; }
.navbar-default .navbar-nav .original-teacher { color: black; }
.navbar-text .fa-user { color: #aaa; }
.logout-form .btn-link { border: 0; line-height: 24px; padding-top: 0; padding-bottom: 0; }
.visualizer button .glyphicon { display: none; }
#example_tests .debug_me { width: 130px; white-space: nowrap; }
#example_tests .debug_me button { font-family: inherit; font-size: 14px; padding: 4px 8px; }
/* Keep the editor width stable before, during and after execution. */
.visualizer > .row > .visualizer-editor-column,
.visualizer > .row > .visualizer-result-column { width: 100%; min-width: 0; }
.visualizer-result-column { clear: both; }
.visualizer-result-column > .col-xs-6 { width: 100%; padding: 0; }
.visualizer_dataviz { overflow: auto; max-width: 100%; padding-bottom: 12px; }
.visualizer_code_toppanel { min-height: 35px; }
.visualizer_vcr { display: flex; flex-wrap: wrap; justify-content: space-between; align-items: center; }
.visualizer_vcr button { margin-right: 0; }
@media (max-width:767px) {
 .navbar-default .navbar-nav > li:first-child > a { margin-left: 16px; }
 .visualizer.has-dataviz > .row > .visualizer-editor-column,
 .visualizer.has-dataviz > .row > .visualizer-result-column { width: 100%; }
}

.knowledge-article { max-width: 900px; padding: 28px 0; }
.knowledge-article section { margin-top: 32px; }
.knowledge-article pre { white-space: pre; overflow: auto; font-size: 14px; }
.knowledge-origin { color: #666; font-size: 14px; }
.knowledge-list li { margin: 12px 0; }
.knowledge-article summary { cursor: pointer; color: #0275d8; margin: 16px 0; }

.teacher-page { padding: 24px 0; }
.teacher-course { margin-top: 28px; }
.teacher-actions { display:flex; gap:10px; flex-wrap:wrap; align-items:center; margin:20px 0 28px; }
.teacher-group-card { border:1px solid #ddd; border-radius:4px; padding:18px 22px; margin:16px 0; }
.teacher-group-card h3 { margin-top:0; }
.invite-row { display:flex; gap:8px; margin:8px 0 14px; }
.invite-row input { min-width:0; flex:1; }
.teacher-filters { display:flex; flex-wrap:wrap; align-items:center; gap:10px; margin:16px 0; }
.teacher-filters input { max-width:300px; }
.teacher-filters select { max-width:260px; }
.teacher-form { max-width:620px; margin:24px 0; }
.teacher-form input:not([type=checkbox]), .teacher-form select { width:100%; }
.teacher-empty { padding:20px 0; color:#666; }
.enrollment-info { max-width:800px; margin:20px auto; padding:16px; border:1px solid #ddd; border-radius:4px; }
.site-messages { margin-top:16px; }
@media(max-width:600px) { .invite-row { flex-direction:column; } .teacher-group-card { padding:14px; } }

.beginner-guide { padding:12px 16px; margin:16px 0; background:#f1f6fa; border-left:3px solid #92b8d6; font-size:14px; }
.beginner-guide h4 { font-size:18px; }
.beginner-guide p:last-child { margin-bottom:0; }

.task-hints { margin:28px 0 20px; font-size:14px; }
.task-hints h3 { font-size:18px; margin-bottom:10px; }
.task-hint { border-top:1px solid #dce6ee; padding:10px 0; }
.task-hint summary { cursor:pointer; color:#48769a; }
.task-hint p { margin:12px 0 8px; }
.task-figure { max-width:480px; margin:16px 0; }
.task-figure img { display:block; width:100%; height:auto; }
.task-figure figcaption { color:#667985; font-size:13px; margin-top:6px; }

.settings-page { max-width:820px; margin:24px auto 40px; }
.settings-section { margin:20px 0; padding:22px 26px; border:1px solid #dce6ee; border-radius:6px; background:#fff; }
.settings-section h2 { margin:0 0 12px; font-size:24px; }
.settings-section h3 { margin:24px 0 10px; font-size:19px; }
.settings-section p { color:#526575; line-height:1.6; }
.settings-actions { display:flex; flex-wrap:wrap; align-items:center; gap:10px; margin:14px 0; }
.settings-actions label { margin:0; }
.settings-solutions summary { cursor:pointer; color:#337ab7; padding:6px 0; }
.settings-solutions #pwa-results { max-height:280px; overflow:auto; margin:10px 0; }
.settings-confirm { margin-top:18px; padding:16px; border:1px solid #e5c9c9; border-radius:4px; background:#fffafa; }
.settings-confirm h3 { margin-top:0; }
@media(max-width:600px) { .settings-section { padding:18px 16px; } .settings-actions .btn { white-space:normal; } }

.settings-actions label:focus-within { outline:2px solid #337ab7; outline-offset:2px; }

.settings-progress-summary { font-size:22px; font-weight:600; }
.settings-progress-groups { display:grid; grid-template-columns:1fr 1fr; gap:24px; margin-bottom:20px; }
.settings-progress-groups h3 { margin:8px 0 12px; }
.settings-progress-groups ul { list-style:none; padding:0; margin:0; max-height:300px; overflow:auto; }
.settings-progress-groups li { padding:7px 0; }
@media(max-width:600px) { .settings-progress-groups { grid-template-columns:1fr; gap:12px; } }

.settings-lesson-progress { margin:12px 0 28px; }
.settings-lesson-row { display:grid; grid-template-columns:1fr auto; gap:6px 16px; padding:12px 0; border-bottom:1px solid #e6edf2; }
.settings-lesson-row span { color:#526575; font-size:14px; }
.settings-lesson-row progress { grid-column:1/-1; width:100%; height:6px; accent-color:#7facca; }
@media(max-width:600px) { .settings-lesson-row { grid-template-columns:1fr; } }

/* Keep task instructions distinct and comfortable to read beside the editor. */
.task-statement { font-size:18px; line-height:1.7; color:#243440; max-width:76ch; margin:20px 0 28px; padding:4px 0 4px 18px; border-left:3px solid #b9d9ef; overflow-wrap:break-word; }
.task-statement .statement-title { font-size:22px; line-height:1.3; font-weight:600; color:#243440; margin:0 0 14px; }
.task-statement p { margin:0 0 14px; }
.task-statement p:last-child { margin-bottom:0; }
.task-statement li { margin-bottom:8px; }
.task-statement code { font-size:.95em; }
.task-statement img { max-width:100%; height:auto; }
@media(max-width:600px) { .task-statement { font-size:18px; padding-left:12px; margin:16px 0 24px; } }

.lesson-theory dfn, .lesson-theory em, .lesson-theory i, .lesson-theory strong, .lesson-theory b { font-weight:700; color:#182c3c; }
.lesson-theory dfn { font-style:normal; }