/* =========================================================
   OFFLINE R PRACTICAL SOLVER
   Invisible Glass UI — matched to index.html
   ========================================================= */

:root {
  color-scheme: dark;
  --bg: #090b12;
  --panel: rgba(19, 22, 34, 0.7);
  --panel-hover: rgba(28, 32, 48, 0.76);
  --border: rgba(195, 202, 255, 0.12);
  --text: #eef0fb;
  --muted: #9ba3b8;
  --accent: #c4c7ff;
  --accent-strong: #a5b4fc;
  --success: #7ce8b5;
  --danger: #ff9eae;
  --radius: 18px;
}

* {
  box-sizing: border-box;
}

html {
  min-height: 100%;
  background: var(--bg);
  scroll-behavior: smooth;
}

body {
  min-height: 100vh;
  margin: 0;
  color: var(--text);
  font-family: Inter, "Segoe UI", Arial, sans-serif;
  font-size: 15px;
  line-height: 1.6;
  background:
    radial-gradient(
      ellipse at 15% 0%,
      rgba(111, 104, 255, 0.12),
      transparent 38rem
    ),
    radial-gradient(
      ellipse at 95% 65%,
      rgba(69, 152, 255, 0.07),
      transparent 34rem
    ),
    var(--bg);
  -webkit-font-smoothing: antialiased;
}

button,
select,
textarea {
  font: inherit;
}

button {
  cursor: pointer;
}

button:disabled {
  cursor: not-allowed;
  opacity: 0.48;
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

h1,
h2,
h3 {
  color: var(--text);
  line-height: 1.25;
}

p {
  color: var(--muted);
}

button:focus-visible,
select:focus-visible,
textarea:focus-visible {
  outline: 2px solid var(--accent-strong);
  outline-offset: 3px;
}

::selection {
  color: white;
  background: rgba(129, 140, 248, 0.4);
}

/* ================= TOP BAR ================= */

.topbar {
  width: 100%;
  min-height: 82px;
  padding: 18px 5%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.07);
  background: rgba(9, 11, 18, 0.65);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
}

.brand {
  display: flex;
  align-items: center;
  gap: 14px;
  min-width: 0;
}

.brand-icon {
  width: 46px;
  height: 46px;
  flex: 0 0 46px;
  display: grid;
  place-items: center;
  border: 1px solid rgba(196, 199, 255, 0.25);
  border-radius: 14px;
  color: #111426;
  background: linear-gradient(135deg, #d4d4ff, #b4c7ff);
  font-size: 25px;
  font-weight: 800;
  box-shadow: 0 0 28px rgba(165, 180, 252, 0.12);
}

.brand h1 {
  margin: 0;
  font-size: 19px;
  font-weight: 750;
  letter-spacing: -0.5px;
}

.brand p {
  margin: 3px 0 0;
  font-size: 12px;
  color: var(--muted);
}

.offline-status {
  flex-shrink: 0;
  display: inline-flex;
  align-items: center;
  gap: 9px;
  padding: 8px 12px;
  border: 1px solid rgba(124, 232, 181, 0.16);
  border-radius: 999px;
  background: rgba(124, 232, 181, 0.045);
  color: #b8e9d1;
  font-size: 12px;
  font-weight: 600;
}

.status-dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--success);
  box-shadow: 0 0 10px rgba(124, 232, 181, 0.55);
}

/* ================= MAIN CONTAINER ================= */

.container {
  width: min(100% - 40px, 820px);
  margin: 0 auto;
  padding: 38px 0 28px;
}

/* ================= HERO ================= */

.hero {
  margin: 0 0 27px;
  padding: 8px 2px 3px;
}

.eyebrow {
  display: inline-block;
  margin-bottom: 12px;
  color: var(--accent-strong);
  font-size: 11px;
  font-weight: 750;
  letter-spacing: 2px;
}

.hero h2 {
  margin-bottom: 12px;
  font-size: clamp(29px, 4.5vw, 42px);
  font-weight: 760;
  letter-spacing: -1.8px;
  background: linear-gradient(110deg, #fff, #c6c8ff 65%, #b3e5ff);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.hero p {
  max-width: 590px;
  margin-bottom: 0;
  font-size: 14px;
  line-height: 1.8;
}

/* ================= SOLVER CARD ================= */

.solver-card,
.result-card {
  min-width: 0;
  padding: 26px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--panel);
  box-shadow:
    0 18px 50px rgba(0, 0, 0, 0.16),
    inset 0 1px rgba(255, 255, 255, 0.025);
  backdrop-filter: blur(22px);
  -webkit-backdrop-filter: blur(22px);
}

.solver-card {
  margin-bottom: 22px;
}

.section-heading {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 25px;
}

.section-heading h3 {
  margin-bottom: 5px;
  font-size: 17px;
}

.section-heading p {
  margin-bottom: 0;
  font-size: 12px;
}

.local-tag {
  flex-shrink: 0;
  padding: 6px 9px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.035);
  color: #c5c8dc;
  font-size: 10px;
  font-weight: 600;
}

/* ================= FORM ================= */

.solver-card label {
  display: block;
  margin: 0 0 8px;
  color: #d8dced;
  font-size: 12px;
  font-weight: 650;
}

#module,
#question {
  display: block;
  width: 100%;
  min-width: 0;
  margin: 0 0 21px;
  color: var(--text);
  background: rgba(5, 7, 13, 0.62);
  border: 1px solid rgba(195, 202, 255, 0.13);
  border-radius: 11px;
  outline: none;
  transition:
    border-color 160ms ease,
    box-shadow 160ms ease;
}

#module {
  height: 46px;
  padding: 0 13px;
  cursor: pointer;
}

#module option {
  color: var(--text);
  background: #141725;
}

#question {
  min-height: 130px;
  padding: 13px 14px;
  resize: vertical;
  line-height: 1.7;
}

#question::placeholder {
  color: #737d92;
}

#module:focus,
#question:focus {
  border-color: var(--accent-strong);
  box-shadow: 0 0 0 3px rgba(165, 180, 252, 0.08);
}

/* ================= FORM FOOTER ================= */

.form-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  margin-top: -3px;
}

#question-count {
  color: var(--muted);
  font-size: 11px;
  overflow-wrap: anywhere;
}

#solve-btn {
  min-height: 43px;
  padding: 10px 17px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 13px;
  border: 1px solid transparent;
  border-radius: 10px;
  color: #111426;
  background: linear-gradient(120deg, #d2d3ff, #bcd1ff);
  font-size: 12px;
  font-weight: 750;
  box-shadow: 0 4px 20px rgba(165, 180, 252, 0.1);
  transition:
    filter 160ms ease,
    box-shadow 160ms ease;
}

#solve-btn:hover {
  filter: brightness(1.08);
  box-shadow: 0 5px 24px rgba(165, 180, 252, 0.18);
}

#solve-btn span {
  font-size: 18px;
  line-height: 1;
}

/* ================= EXAMPLE BUTTONS ================= */

.examples {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 9px;
  margin-top: 23px;
  padding-top: 18px;
  border-top: 1px solid rgba(255, 255, 255, 0.065);
}

.examples-label {
  width: 100%;
  margin-bottom: 2px;
  color: var(--muted);
  font-size: 11px;
  font-weight: 650;
}

.example-btn {
  max-width: 100%;
  min-height: 34px;
  padding: 7px 10px;
  border: 1px solid rgba(195, 202, 255, 0.12);
  border-radius: 9px;
  color: #c7cce0;
  background: rgba(255, 255, 255, 0.035);
  font-size: 11px;
  text-align: left;
  transition:
    background 160ms ease,
    border-color 160ms ease;
}

.example-btn:hover {
  border-color: rgba(165, 180, 252, 0.35);
  background: rgba(165, 180, 252, 0.08);
}

/* ================= OUTPUT CARD ================= */

.result-card {
  margin-bottom: 22px;
}

.result-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 18px;
  margin-bottom: 19px;
}

.result-label {
  display: inline-block;
  margin-bottom: 7px;
  color: var(--accent-strong);
  font-size: 10px;
  font-weight: 800;
  letter-spacing: 2px;
}

.result-header h3 {
  margin-bottom: 0;
  font-size: 16px;
  font-weight: 650;
  overflow-wrap: anywhere;
}

.result-actions {
  display: flex;
  flex-shrink: 0;
  align-items: center;
  gap: 8px;
}

.secondary-btn {
  min-height: 35px;
  padding: 7px 11px;
  border: 1px solid var(--border);
  border-radius: 9px;
  color: #d1d6e9;
  background: rgba(255, 255, 255, 0.04);
  font-size: 11px;
  font-weight: 650;
  transition:
    background 160ms ease,
    border-color 160ms ease;
}

.secondary-btn:hover:not(:disabled) {
  border-color: rgba(165, 180, 252, 0.3);
  background: rgba(255, 255, 255, 0.08);
}

#copy-btn {
  color: var(--success);
  border-color: rgba(124, 232, 181, 0.18);
}

#clear-btn {
  color: #d7d9e8;
}

/* ================= MESSAGE ================= */

.message {
  margin-bottom: 14px;
  padding: 11px 13px;
  border: 1px solid rgba(165, 180, 252, 0.14);
  border-radius: 10px;
  color: #d4d9f0;
  background: rgba(165, 180, 252, 0.06);
  font-size: 12px;
  overflow-wrap: anywhere;
}

.message[hidden] {
  display: none;
}

.message.success {
  color: var(--success);
}

.message.error {
  color: var(--danger);
}

/* ================= CODE OUTPUT ================= */

.code-output {
  display: block;
  width: 100%;
  min-width: 0;
  max-width: 100%;
  min-height: 115px;
  max-height: 520px;
  margin: 0;
  padding: 17px;
  overflow: auto;
  border: 1px solid rgba(195, 202, 255, 0.1);
  border-radius: 12px;
  color: #dce5ff;
  background: rgba(3, 5, 10, 0.76);
  font-family: "Cascadia Code", Consolas, "Courier New", monospace;
  font-size: 12px;
  line-height: 1.85;
  tab-size: 2;
  white-space: pre-wrap;
  overflow-wrap: anywhere;
}

#code-content {
  color: inherit;
  font: inherit;
  white-space: inherit;
  overflow-wrap: inherit;
}

/* ================= OUTPUT FOOTER ================= */

.result-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin-top: 14px;
  color: #858ea5;
  font-size: 10px;
}

#result-info {
  overflow-wrap: anywhere;
}

/* ================= NOTICE ================= */

.notice {
  margin: 0 0 25px;
  padding: 17px 19px;
  border: 1px solid rgba(245, 196, 120, 0.13);
  border-radius: 13px;
  background: rgba(245, 196, 120, 0.035);
}

.notice strong {
  display: block;
  margin-bottom: 5px;
  color: #e8d1a6;
  font-size: 12px;
}

.notice p {
  margin: 0;
  color: #a7a9b7;
  font-size: 12px;
  line-height: 1.8;
}

/* ================= PAGE FOOTER ================= */

.footer {
  padding: 23px 20px 26px;
  border-top: 1px solid rgba(255, 255, 255, 0.06);
  text-align: center;
}

.footer p {
  margin: 3px 0;
  color: #737d92;
  font-size: 11px;
}

/* ================= RESPONSIVE ================= */

@media (max-width: 640px) {
  .topbar {
    min-height: 72px;
    padding: 14px 18px;
    gap: 10px;
  }

  .brand {
    gap: 10px;
  }

  .brand-icon {
    width: 39px;
    height: 39px;
    flex-basis: 39px;
    border-radius: 11px;
    font-size: 21px;
  }

  .brand h1 {
    font-size: 15px;
  }

  .brand p {
    max-width: 190px;
    font-size: 10px;
  }

  .offline-status {
    gap: 6px;
    padding: 7px 8px;
    font-size: 10px;
  }

  .container {
    width: calc(100% - 28px);
    padding-top: 27px;
  }

  .hero {
    margin-bottom: 21px;
  }

  .hero h2 {
    font-size: clamp(28px, 8vw, 36px);
    letter-spacing: -1px;
  }

  .hero p {
    font-size: 13px;
  }

  .solver-card,
  .result-card {
    padding: 18px;
    border-radius: 15px;
  }

  .section-heading {
    flex-direction: column;
    gap: 10px;
    margin-bottom: 22px;
  }

  .local-tag {
    align-self: flex-start;
  }

  .result-header {
    flex-direction: column;
    gap: 13px;
  }

  .result-actions {
    width: 100%;
  }

  .result-actions button {
    flex: 1;
  }

  .examples {
    align-items: stretch;
  }

  .example-btn {
    flex: 1 1 140px;
  }

  .form-footer {
    align-items: center;
  }

  #solve-btn {
    padding-inline: 12px;
  }

  .code-output {
    padding: 13px;
    font-size: 11px;
  }
}

@media (max-width: 380px) {
  .topbar {
    align-items: flex-start;
  }

  .brand p {
    max-width: 145px;
  }

  .offline-status {
    font-size: 9px;
  }

  .form-footer {
    align-items: stretch;
    flex-direction: column;
  }

  #solve-btn {
    width: 100%;
  }

  .result-footer {
    align-items: flex-start;
    flex-direction: column;
    gap: 4px;
  }
}

/* Respect reduced-motion preferences */

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    transition: none !important;
  }
}