/* IELTS 30-day challenge (/study/ielts/challenge) and its certificate page. Square like the rest of Study, on the
 * IELTS roadmap tokens (--ir-*). A day's state is written in words as well as shown by colour. */
.ch-page { --ch-gap: clamp(16px, 2.6vw, 28px); }
.ch-page :is(h1, h2, h3, h4) { font-family: var(--ir-font); letter-spacing: normal; text-transform: none; }
.ch-page .text-link { background: none; border: 0; padding: 0; color: var(--ir-pen); font: 600 15px/1.5 var(--ir-font); text-decoration: underline; cursor: pointer; text-align: left; }
.ch-page .btn { white-space: normal; text-align: center; }
.ch-page .btn:disabled { opacity: .55; cursor: wait; }
.ch-hint { margin: 8px 0 0; color: var(--ir-muted); font: 400 14px/1.6 var(--ir-font); }
.ch-on-ink, .ch-page .text-link.ch-on-ink { color: var(--ir-on-ink-muted); }
.ch-page .text-link.ch-on-ink { color: var(--ir-hi); }

/* ---------- Hero and the round panel ---------- */
.ch-hero-inner { display: grid; grid-template-columns: minmax(0, 1.3fr) minmax(280px, .85fr); gap: 28px 56px; align-items: center; padding-block: clamp(32px, 5vw, 64px); }
.ch-round { display: grid; gap: 12px; padding: 24px; border: 1px solid #4a4438; background: var(--ir-ink-2); min-width: 0; }
.ch-round h2 { margin: 0; color: var(--ir-hi); font-size: 22px; line-height: 1.3; }
.ch-round-date { margin: 0; color: var(--ir-on-ink); font: 600 17px/1.5 var(--ir-font); }
.ch-countdown-label { margin: 0 0 6px; color: var(--ir-on-ink-muted); font: 500 14px/1.4 var(--ir-font); }
.ch-countdown-units { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 8px; }
.ch-countdown-units > span { display: grid; gap: 2px; padding: 10px 8px; border: 1px solid #4a4438; text-align: center; }
.ch-countdown-units strong { color: var(--ir-on-ink); font: 700 32px/1 var(--ir-font); font-variant-numeric: tabular-nums; }
.ch-countdown-units small { color: var(--ir-on-ink-muted); font: 500 13px/1.3 var(--ir-font); }
.ch-joined { margin: 0; color: var(--ir-hi); font: 600 15px/1.5 var(--ir-font); }
.ch-round-actions { display: flex; flex-wrap: wrap; align-items: center; gap: 10px 18px; }
.ch-round-actions .btn { min-height: 48px; }
.ch-in { margin: 0; flex: 1 1 100%; color: var(--ir-on-ink); font: 600 16px/1.5 var(--ir-font); }
.ch-in::before { content: ""; display: inline-block; width: 12px; height: 12px; margin-right: 8px; background: var(--ir-done); border: 2px solid var(--ir-on-ink); vertical-align: -1px; }
.ch-round-note { margin: 0; color: var(--ir-on-ink-muted); font: 400 14px/1.55 var(--ir-font); }

/* ---------- What you get ---------- */
.ch-get { padding-block: clamp(32px, 5vw, 56px); background: var(--ir-paper); color: var(--ir-text); }
.ch-get h2, .ch-plan h2, .ch-rules h2 { margin: 0 0 18px; color: var(--ir-ink); font-size: clamp(26px, 3vw, 36px); line-height: 1.2; }
.ch-get-list { list-style: none; margin: 0; padding: 0; display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 12px; }
.ch-get-list li { display: grid; gap: 6px; align-content: start; padding: 18px 20px; background: var(--ir-card); border: 2px solid var(--ir-ink); font: 400 15px/1.6 var(--ir-font); min-width: 0; }
.ch-get-list li[hidden] { display: none; }
.ch-get-list strong { color: var(--ir-ink); font: 700 17px/1.4 var(--ir-font); }

/* ---------- The student's round ---------- */
.ch-me { padding-block: clamp(28px, 4vw, 48px); background: var(--ir-ink); color: var(--ir-on-ink); }
.ch-me-head h2 { margin: 0 0 6px; color: var(--ir-on-ink); font-size: clamp(24px, 2.6vw, 32px); }
.ch-me-note { margin: 0 0 18px; color: var(--ir-on-ink-muted); font: 400 16px/1.6 var(--ir-font); }
.ch-stats { list-style: none; margin: 0 0 18px; padding: 0; display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 10px; }
.ch-stats li { display: grid; gap: 4px; padding: 14px 16px; border: 1px solid #4a4438; background: var(--ir-ink-2); min-width: 0; }
.ch-stat-label { color: var(--ir-on-ink-muted); font: 500 13px/1.4 var(--ir-font); }
.ch-stats strong { color: var(--ir-hi); font: 700 30px/1.1 var(--ir-font); font-variant-numeric: tabular-nums; }
.ch-stats small { color: var(--ir-on-ink-muted); font: 400 13px/1.4 var(--ir-font); }
.ch-cert { display: grid; grid-template-columns: minmax(0, 1fr) auto; gap: 12px 24px; align-items: center; padding: 16px 18px; border: 1px solid #4a4438; }
.ch-cert-text p { margin: 0 0 10px; font: 600 16px/1.5 var(--ir-font); }
.ch-cert .progress { background: #4a4438; }
.ch-cert .progress-fill { background: var(--ir-hi); }
.ch-cert .progress-fill[data-complete="true"] { background: #4fbf86; }
.ch-cert-actions:empty { display: none; }
.ch-zalo { margin: 16px 0 0; }
.ch-zalo .btn-ink, .ch-me .btn-ink { border-color: var(--ir-on-ink); }
.ch-switch { margin-top: 16px; }
.ch-switch .text-link { color: var(--ir-hi); }
.ch-switch .ch-hint { color: var(--ir-on-ink-muted); }

/* ---------- The 30 days ---------- */
.ch-plan { padding-block: clamp(32px, 5vw, 56px); background: var(--ir-paper); color: var(--ir-text); }
.ch-plan-head { max-width: 48em; margin-bottom: 8px; }
.ch-plan-note { margin: 0; font: 400 16px/1.6 var(--ir-font); }
.ch-status { min-height: 1.5em; margin: 12px 0 0; color: var(--ir-done); font: 600 15px/1.5 var(--ir-font); }
.ch-status.ch-error { color: #9b2c1b; }
.ch-weeks { outline: none; }
.ch-week { margin-top: 28px; }
.ch-week h3 { margin: 0 0 12px; padding-bottom: 8px; border-bottom: 2px solid var(--ir-ink); color: var(--ir-ink); font-size: 20px; }
.ch-days { list-style: none; margin: 0; padding: 0; display: grid; grid-template-columns: repeat(auto-fill, minmax(min(100%, 280px), 1fr)); gap: 12px; }
.ch-days + .ch-days { margin-top: 12px; }
.ch-day { display: flex; flex-direction: column; gap: 8px; padding: 16px 18px; background: var(--ir-card); border: 2px solid var(--ir-line); min-width: 0; scroll-margin-top: 16px; }
.ch-day-head { display: flex; flex-wrap: wrap; align-items: center; gap: 6px 10px; }
.ch-day-n { padding: 2px 8px; background: var(--ir-ink); color: var(--ir-on-ink); font: 700 14px/1.6 var(--ir-font); }
.ch-day-date { color: var(--ir-muted); font: 500 14px/1.5 var(--ir-font); }
.ch-badge { margin-left: auto; padding: 1px 8px; font: 600 12px/1.6 var(--ir-font); border: 1px solid currentColor; }
.ch-badge-free { color: var(--ir-done); }
.ch-badge-pro { color: var(--ir-exercise); }
.ch-day h4 { margin: 0; color: var(--ir-ink); font-size: 17px; line-height: 1.4; }
.ch-day-task { margin: 0; font: 400 15px/1.55 var(--ir-font); }
.ch-day-meta { display: flex; flex-wrap: wrap; gap: 4px 14px; margin: 0; color: var(--ir-muted); font: 500 13px/1.5 var(--ir-font); }
.ch-links { list-style: none; margin: 0; padding: 0; display: grid; gap: 4px; }
.ch-links a { display: grid; gap: 2px; padding: 6px 8px; border: 1px solid var(--ir-line); color: var(--ir-ink); text-decoration: none; font: 500 14px/1.45 var(--ir-font); overflow-wrap: anywhere; }
.ch-links a:hover, .ch-links a:focus-visible { background: var(--ir-hi); border-color: var(--ir-ink); }
.ch-link-kind { font-weight: 700; }
.ch-link-title { color: var(--ir-text); }
.ch-day-status { margin-top: auto; color: var(--ir-muted); font: 600 14px/1.5 var(--ir-font); }
.ch-day-status:empty { display: none; }
.ch-day-actions { display: grid; gap: 6px; justify-items: start; }
.ch-day-actions:empty { display: none; }
.ch-day-actions .ch-hint { margin: 0; }
.ch-day[data-state="today"] { border-color: var(--ir-ink); box-shadow: 6px 6px 0 var(--ir-hi); }
.ch-day[data-state="today"] .ch-day-status { color: var(--ir-ink); }
.ch-day[data-state="done"] { border-color: var(--ir-done); background: var(--ir-done-soft); }
.ch-day[data-state="done"] .ch-day-status { color: var(--ir-done); }
.ch-day[data-state="done"] .ch-day-status::before { content: ""; display: inline-block; width: 14px; height: 14px; margin-right: 6px; vertical-align: -2px;
  background: var(--ir-done) url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 16 16'%3E%3Cpath d='M3 8.5l3 3 7-7' fill='none' stroke='white' stroke-width='2.4'/%3E%3C/svg%3E") center/11px no-repeat; }
.ch-day[data-state="catchup"] { border-color: var(--ir-exercise); }
.ch-day[data-state="catchup"] .ch-day-status { color: var(--ir-exercise); }
.ch-day[data-state="upcoming"], .ch-day[data-state="missed"] { opacity: .78; }
.ch-day[data-state="pro"] .ch-day-status { color: var(--ir-exercise); }
.ch-lock { margin-top: 12px; padding: 20px 22px; background: var(--ir-ink); color: var(--ir-on-ink); border: 2px solid var(--ir-ink); }
.ch-lock h4 { margin: 0 0 8px; color: var(--ir-on-ink); font-size: clamp(20px, 2.2vw, 26px); line-height: 1.3; }
.ch-lock p:not(.ielts-kicker) { max-width: 44em; margin: 0 0 16px; color: var(--ir-on-ink-muted); font: 400 16px/1.6 var(--ir-font); }

/* ---------- Leaderboard and display name ---------- */
.ch-board-wrap { padding-block: clamp(28px, 4vw, 48px); background: var(--ir-paper); color: var(--ir-text); border-top: 2px solid var(--ir-ink); }
.ch-board-grid { display: grid; grid-template-columns: minmax(0, 1fr) minmax(260px, 340px); gap: var(--ch-gap); align-items: start; }
.ch-board-box, .ch-profile { background: var(--ir-card); border: 2px solid var(--ir-ink); padding: clamp(18px, 3vw, 28px); min-width: 0; }
.ch-board-box h2 { margin: 0 0 4px; color: var(--ir-ink); font-size: clamp(22px, 2.4vw, 30px); }
.ch-board { list-style: none; margin: 14px 0 0; padding: 0; display: grid; }
.ch-board li { display: grid; grid-template-columns: 3.2em minmax(0, 1fr) auto auto; gap: 4px 14px; align-items: baseline; padding: 10px 6px; border-bottom: 1px solid var(--ir-line); font: 400 15px/1.5 var(--ir-font); }
.ch-board li.ch-board-empty { display: block; color: var(--ir-muted); }
.ch-board li.ch-me-row { background: var(--ir-hi); }
.ch-board-rank { font-weight: 700; color: var(--ir-ink); font-variant-numeric: tabular-nums; }
.ch-board-name { font-weight: 600; color: var(--ir-ink); overflow-wrap: anywhere; }
.ch-board-name small { margin-left: 8px; padding: 0 6px; background: var(--ir-ink); color: var(--ir-on-ink); font: 600 12px/1.6 var(--ir-font); }
.ch-board-points { font-weight: 700; color: var(--ir-ink); font-variant-numeric: tabular-nums; }
.ch-board-days { color: var(--ir-muted); font-size: 14px; }
.ch-profile h3 { margin: 0 0 12px; color: var(--ir-ink); font-size: 19px; }
.ch-profile label[for] { display: block; margin: 0 0 6px; color: var(--ir-ink); font: 600 15px/1.4 var(--ir-font); }
.ch-profile input:not([type]) { box-sizing: border-box; width: 100%; padding: 10px 12px; border: 2px solid var(--ir-line); border-radius: 0; background: #fff; color: var(--ir-ink); font: 400 16px/1.5 var(--ir-font); }
.ch-profile input:focus { outline: 3px solid var(--ir-pen); outline-offset: 1px; border-color: var(--ir-ink); }
.ch-check { display: flex; gap: 10px; align-items: flex-start; margin: 14px 0; font: 500 15px/1.5 var(--ir-font); cursor: pointer; }
.ch-check input { width: 20px; height: 20px; margin: 2px 0 0; accent-color: var(--ir-ink); flex: 0 0 auto; }

/* ---------- Rules ---------- */
.ch-rules { padding-block: clamp(32px, 5vw, 56px); background: var(--ir-paper); color: var(--ir-text); border-top: 2px solid var(--ir-ink); }
.ch-rules-list { max-width: 52em; margin: 0; padding-left: 22px; font: 400 16px/1.65 var(--ir-font); }
.ch-rules-list li { margin-bottom: 8px; }
.ch-page .disclaimer { margin: 24px 0 0; color: var(--ir-muted); font: 400 13px/1.6 var(--ir-font); }

/* ---------- Certificate ---------- */
.ch-cert-page { padding-block: clamp(28px, 5vw, 64px); background: var(--ir-paper); color: var(--ir-text); }
.ch-certificate { position: relative; max-width: 760px; margin: 0 auto; padding: clamp(24px, 5vw, 56px); background: var(--ir-card); border: 2px solid var(--ir-ink); box-shadow: 10px 10px 0 var(--ir-hi), 10px 10px 0 2px var(--ir-ink); text-align: center; }
.ch-certificate::before { content: ""; position: absolute; inset: 10px; border: 1px solid var(--ir-line); pointer-events: none; }
.ch-cert-kicker { margin: 0 0 18px; color: var(--ir-exercise); font: 700 14px/1.4 var(--ir-font); text-transform: uppercase; letter-spacing: .08em; }
.ch-cert-intro { margin: 0; color: var(--ir-muted); font: 400 16px/1.5 var(--ir-font); }
.ch-cert-name { margin: 6px 0 10px; color: var(--ir-ink); font-size: clamp(34px, 6vw, 56px); line-height: 1.15; overflow-wrap: anywhere; }
.ch-cert-what { max-width: 30em; margin: 0 auto 26px; font: 500 clamp(16px, 2vw, 19px)/1.55 var(--ir-font); color: var(--ir-ink); }
.ch-cert-facts { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 10px; margin: 0 0 26px; }
.ch-cert-facts > div { padding: 12px 8px; border: 2px solid var(--ir-ink); min-width: 0; }
.ch-cert-facts > div[data-gain="up"] { background: var(--ir-hi); }
.ch-cert-facts dt { color: var(--ir-muted); font: 600 12px/1.4 var(--ir-font); }
.ch-cert-facts dd { display: grid; margin: 6px 0 0; color: var(--ir-ink); font: 700 30px/1.1 var(--ir-font); font-variant-numeric: tabular-nums; }
.ch-cert-facts dd small { color: var(--ir-muted); font: 500 12px/1.5 var(--ir-font); }
.ch-cert-seal { display: inline-flex; align-items: center; gap: 10px; margin: 0; color: var(--ir-ink); font: 700 15px/1.4 var(--ir-font); }
.ch-cert-note { margin: 14px 0 0; color: var(--ir-muted); font: 400 12px/1.5 var(--ir-font); }
.ch-share { display: flex; flex-wrap: wrap; justify-content: center; align-items: center; gap: 10px 14px; max-width: 760px; margin: 34px auto 0; }
.ch-share .ch-hint { flex: 1 1 100%; text-align: center; min-height: 1.5em; }
.ch-cert-cta { max-width: 760px; margin: 34px auto 0; padding: 22px 24px; background: var(--ir-ink); color: var(--ir-on-ink); }
.ch-cert-cta h2 { margin: 0 0 8px; color: var(--ir-on-ink); font-size: 24px; }
.ch-cert-cta p { margin: 0 0 16px; color: var(--ir-on-ink-muted); font: 400 16px/1.6 var(--ir-font); }

@media (max-width: 1000px) {
  .ch-hero-inner, .ch-board-grid { grid-template-columns: minmax(0, 1fr); }
  .ch-get-list { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .ch-stats { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}
@media (max-width: 640px) {
  .ch-get-list, .ch-cert { grid-template-columns: minmax(0, 1fr); }
  .ch-cert-facts { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .ch-countdown-units strong { font-size: 26px; }
  .ch-stats strong { font-size: 26px; }
  .ch-board li { grid-template-columns: 2.6em minmax(0, 1fr) auto; }
  .ch-board-days { grid-column: 2 / -1; }
  .ch-round-actions .btn { flex: 1 1 100%; }
}