:root {
  --paper: #f6f4ee;
  --card: #ffffff;
  --ink: #17191c;
  --muted: #5c6168;
  --line: #e2ded4;
  --blue: #1f3a8a;
  --blue-soft: #e8ecf8;
  --green: #1d7348;
  --green-soft: #e5f2ea;
  --red: #b4232c;
  --radius: 10px;
  --font: ui-sans-serif, system-ui, -apple-system, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
}

* {
  box-sizing: border-box;
}

html {
  scrollbar-color: #c9c4b8 var(--paper);
  scroll-padding-top: 112px;
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font: 16px/1.5 var(--font);
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--blue);
}

h1,
h2 {
  line-height: 1.2;
  margin: 0;
  letter-spacing: -0.01em;
}
h1 {
  font-size: 1.6rem;
}
h2 {
  font-size: 1.1rem;
}
p {
  margin: 0.4rem 0;
}
.sub {
  color: var(--muted);
  font-size: 0.92rem;
  margin: 0.2rem 0 0;
}
.eyebrow {
  color: var(--blue);
  font-weight: 600;
  font-size: 0.85rem;
  margin: 0 0 0.25rem;
}

/* ---------- header ---------- */
.top {
  position: sticky;
  top: 0;
  z-index: 10;
  background: var(--card);
  border-bottom: 1px solid var(--line);
}
.top-inner {
  max-width: 860px;
  margin: 0 auto;
  padding: 0.6rem 1rem 0;
}
.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  text-decoration: none;
  color: var(--ink);
  font-size: 1.05rem;
}
.brand b {
  color: var(--blue);
}
.tabs {
  display: flex;
  gap: 1.25rem;
  overflow-x: auto;
  scrollbar-width: none;
  margin-top: 0.35rem;
}
.tabs a {
  padding: 0.55rem 0 0.6rem;
  color: var(--muted);
  text-decoration: none;
  font-weight: 600;
  font-size: 0.95rem;
  border-bottom: 3px solid transparent;
  white-space: nowrap;
}
.tabs a:hover {
  color: var(--ink);
}
.tabs a[aria-current='page'] {
  color: var(--ink);
  border-bottom-color: var(--blue);
}

/* ---------- layout ---------- */
main {
  max-width: 860px;
  margin: 0 auto;
  padding: 1.25rem 1rem 2rem;
  outline: none;
}
main > h1 + .sub {
  margin-bottom: 1rem;
}
.foot {
  max-width: 860px;
  margin: 0 auto;
  padding: 0 1rem 2.5rem;
  color: var(--muted);
  font-size: 0.85rem;
}
.loading {
  padding: 3rem 1rem;
  text-align: center;
  color: var(--muted);
}
.notice {
  background: var(--blue-soft);
  border: 1px solid #c9d3f0;
  border-radius: var(--radius);
  padding: 0.7rem 0.9rem;
  margin: 0 0 1rem;
}

.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1rem;
  margin: 0 0 1rem;
}
.card > h2 + p,
.card > h2 + .sub {
  margin-top: 0.3rem;
}
.empty {
  text-align: center;
  padding: 2rem 1rem;
}

/* ---------- day ---------- */
.day-head {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
}
.today-mark {
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--green);
  vertical-align: middle;
  margin-left: 0.3rem;
}
.day-nav {
  display: flex;
  gap: 0.4rem;
}
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 44px;
  height: 40px;
  padding: 0 0.8rem;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--card);
  color: var(--ink);
  text-decoration: none;
  font-weight: 600;
}
.btn:hover {
  border-color: var(--blue);
  color: var(--blue);
}
.btn.disabled {
  opacity: 0.35;
}

.progress-row {
  margin: 1rem 0 1.1rem;
}
.meter {
  height: 8px;
  background: #e9e5db;
  border-radius: 4px;
  overflow: hidden;
}
.meter span {
  display: block;
  height: 100%;
  background: var(--green);
  transition: width 0.25s ease;
}

.session-head {
  padding-bottom: 0.6rem;
  border-bottom: 1px solid var(--line);
}
.tasks {
  list-style: none;
  margin: 0;
  padding: 0;
}
.task {
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
  padding: 0.8rem 0;
  border-bottom: 1px solid #efece5;
}
.task:last-child {
  border-bottom: 0;
  padding-bottom: 0.2rem;
}
.check {
  flex: none;
  width: 26px;
  height: 26px;
  margin-top: 1px;
  border: 2px solid #b8b2a5;
  border-radius: 6px;
  background: var(--card);
  cursor: pointer;
  position: relative;
}
.check:hover {
  border-color: var(--green);
}
.check:focus-visible,
.btn:focus-visible,
.act:focus-visible,
.tabs a:focus-visible {
  outline: 3px solid #9fb2ea;
  outline-offset: 2px;
}
.task.done .check {
  background: var(--green);
  border-color: var(--green);
}
.task.done .check::after {
  content: '';
  position: absolute;
  left: 7px;
  top: 2px;
  width: 7px;
  height: 13px;
  border: solid #fff;
  border-width: 0 3px 3px 0;
  transform: rotate(45deg);
}
.task-body {
  flex: 1;
  min-width: 0;
}
.task-title {
  margin: 0;
  font-weight: 600;
}
.task.done .task-title {
  color: var(--muted);
  text-decoration: line-through;
  text-decoration-color: #b8b2a5;
}
.task-detail {
  margin: 0.15rem 0 0;
  color: var(--muted);
  font-size: 0.9rem;
}
.mins {
  flex: none;
  color: var(--muted);
  font-size: 0.85rem;
  font-variant-numeric: tabular-nums;
  padding-top: 2px;
}
.acts {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-top: 0.5rem;
}
.act {
  display: inline-flex;
  align-items: center;
  min-height: 36px;
  padding: 0 0.75rem;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--card);
  color: var(--blue);
  font: 600 0.88rem var(--font);
  text-decoration: none;
  cursor: pointer;
}
.act:hover {
  border-color: var(--blue);
  background: var(--blue-soft);
}
.act.file input {
  position: absolute;
  width: 1px;
  height: 1px;
  opacity: 0;
}

textarea {
  width: 100%;
  margin-top: 0.6rem;
  padding: 0.7rem;
  border: 1px solid var(--line);
  border-radius: 8px;
  font: 0.95rem/1.5 var(--font);
  color: var(--ink);
  background: #fdfcf9;
  resize: vertical;
}
textarea:focus {
  outline: 2px solid #9fb2ea;
  border-color: var(--blue);
}

/* ---------- plan ---------- */
.week h2 {
  margin-bottom: 0.4rem;
}
.week h2 .sub {
  font-weight: 400;
  font-size: 0.85rem;
}
.plan-days {
  list-style: none;
  margin: 0;
  padding: 0;
}
.plan-day {
  display: grid;
  grid-template-columns: 6.5rem 1fr 3rem;
  gap: 0.5rem;
  padding: 0.55rem 0.4rem;
  border-top: 1px solid #efece5;
  color: var(--ink);
  text-decoration: none;
}
.plan-day:hover {
  background: #faf8f3;
}
.plan-day.is-today {
  background: var(--blue-soft);
  border-radius: 6px;
  font-weight: 600;
}
.pd-date {
  color: var(--muted);
  font-variant-numeric: tabular-nums;
}
.pd-status {
  text-align: right;
  color: var(--muted);
  font-size: 0.85rem;
}
.plan-day.is-done .pd-status {
  color: var(--green);
  font-weight: 700;
}

/* ---------- content ---------- */
.tbl {
  width: 100%;
  border-collapse: collapse;
  margin: 0.7rem 0 0.3rem;
  font-size: 0.92rem;
}
.tbl th,
.tbl td {
  text-align: left;
  vertical-align: top;
  padding: 0.5rem 0.5rem 0.5rem 0;
  border-bottom: 1px solid #efece5;
}
.tbl th {
  color: var(--muted);
  font-weight: 600;
  font-size: 0.82rem;
}
.card ol,
.plain {
  margin: 0.5rem 0 0;
  padding-left: 1.2rem;
}
.card li {
  margin: 0.3rem 0;
}
.plain {
  list-style: none;
  padding: 0;
}
.plain li {
  padding: 0.45rem 0;
  border-bottom: 1px solid #efece5;
}
.plain li:last-child {
  border-bottom: 0;
}
details {
  margin-top: 0.6rem;
}
summary {
  cursor: pointer;
  font-weight: 600;
  color: var(--blue);
}
pre.note {
  white-space: pre-wrap;
  font: 0.92rem/1.5 var(--font);
  margin: 0.5rem 0 0;
  padding: 0.7rem;
  background: #faf8f3;
  border: 1px solid #efece5;
  border-radius: 8px;
}

@media (max-width: 560px) {
  h1 {
    font-size: 1.35rem;
  }
  .tabs {
    gap: 1rem;
  }
  .plan-day {
    grid-template-columns: 5.6rem 1fr 2.6rem;
    font-size: 0.92rem;
  }
  .tbl {
    font-size: 0.85rem;
  }
  .card {
    padding: 0.85rem;
  }
}

.vol-when {
  margin: 0 0 0.1rem;
  color: var(--blue);
  font-weight: 600;
  font-size: 0.82rem;
}
.volumes li p {
  margin-top: 0.1rem;
}
.tbl td:first-child {
  white-space: nowrap;
}

/* ---------- flashcards ---------- */
.flash {
  text-align: center;
  padding: 1.4rem 1rem 1.2rem;
}
.flash-badge {
  display: inline-block;
  margin: 0 0 0.4rem;
  color: var(--green);
  font-weight: 700;
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}
.flash-meta {
  color: var(--muted);
  font-size: 0.85rem;
  margin: 0;
}
.flash-word {
  font-size: 2.1rem;
  font-weight: 700;
  line-height: 1.2;
  margin: 0.3rem 0 0.6rem;
  word-break: break-word;
}
.g-m {
  color: var(--blue);
}
.g-f {
  color: var(--red);
}
.g-mf {
  color: #6b3fa0;
}
.flash-back {
  border-top: 1px solid var(--line);
  margin-top: 1rem;
  padding-top: 1rem;
}
.flash-answer {
  font-size: 1.25rem;
  font-weight: 600;
  margin: 0 0 0.3rem;
}
.examples {
  list-style: none;
  margin: 0.8rem auto 0;
  padding: 0;
  max-width: 34rem;
  text-align: left;
}
.examples li {
  padding: 0.45rem 0;
  border-top: 1px solid #efece5;
}
.ex-fr {
  display: block;
  font-weight: 600;
}
.ex-en {
  display: block;
  color: var(--muted);
  font-size: 0.92rem;
}
.btn.reveal {
  width: 100%;
  max-width: 22rem;
  height: 52px;
  margin-top: 1rem;
  background: var(--blue);
  border-color: var(--blue);
  color: #fff;
  font-size: 1.05rem;
}
.btn.reveal:hover {
  color: #fff;
  background: #182f73;
}
.rate {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 0.5rem;
  margin-top: 1.1rem;
}
.rate-btn {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.1rem;
  min-height: 58px;
  padding: 0.5rem 0.2rem;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--card);
  font: 0.95rem var(--font);
  color: var(--ink);
  cursor: pointer;
}
.rate-btn span {
  color: var(--muted);
  font-size: 0.8rem;
}
.rate-btn.r1 {
  border-color: #e7b9bc;
  background: #fbf1f1;
}
.rate-btn.r3 {
  border-color: #b9d9c6;
  background: var(--green-soft);
}
.rate-btn:hover {
  border-color: var(--ink);
}
.rate-btn:focus-visible,
.btn.reveal:focus-visible {
  outline: 3px solid #9fb2ea;
  outline-offset: 2px;
}
.kbd {
  font-size: 0.78rem;
  margin-top: 0.6rem;
}
.flash-done {
  padding: 2rem 1rem;
}

/* ---------- forms ---------- */
.form {
  display: grid;
  gap: 0.7rem;
  margin-top: 0.7rem;
}
.form label {
  display: grid;
  gap: 0.3rem;
  font-weight: 600;
  font-size: 0.92rem;
}
.form input,
.form select {
  height: 44px;
  padding: 0 0.7rem;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fdfcf9;
  font: 1rem var(--font);
  color: var(--ink);
}
.form input:focus,
.form select:focus {
  outline: 2px solid #9fb2ea;
  border-color: var(--blue);
}
.form.inline {
  grid-template-columns: 1fr auto;
  align-items: end;
}
.btn.primary {
  background: var(--blue);
  border-color: var(--blue);
  color: #fff;
}
.btn.primary:hover {
  color: #fff;
  background: #182f73;
}
.act.danger {
  color: var(--red);
}
.act.danger:hover {
  border-color: var(--red);
  background: #fbf1f1;
}
.mycards li {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 0.75rem;
}
.toggle {
  display: flex;
  gap: 0.6rem;
  align-items: center;
  margin-top: 0.4rem;
}
.toggle input {
  width: 20px;
  height: 20px;
}
code {
  font-size: 0.88em;
  background: #f1eee6;
  padding: 0.05rem 0.3rem;
  border-radius: 4px;
}

/* ---------- sync ---------- */
.pair {
  display: grid;
  grid-template-columns: 180px 1fr;
  gap: 1rem;
  align-items: center;
  margin-top: 0.9rem;
}
.qr {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 0.4rem;
}
.qr svg {
  display: block;
  width: 100%;
  height: auto;
}

@media (max-width: 560px) {
  .flash-word {
    font-size: 1.8rem;
  }
  .pair {
    grid-template-columns: 1fr;
  }
  .qr {
    max-width: 220px;
  }
  .form.inline {
    grid-template-columns: 1fr;
  }
}
.flash-word.flash-sentence {
  font-size: 1.45rem;
  font-weight: 600;
  line-height: 1.35;
}

/* ---------- streak ---------- */
.streak {
  margin: 0.45rem 0 0;
  font-size: 0.92rem;
  color: var(--muted);
}
.streak b {
  color: var(--ink);
}
.streak.on {
  color: var(--green);
}
.streak.on b {
  color: var(--green);
}