/* ===========================================================================
   MagicForge Lessons — design system
   Two surfaces, on purpose:
     · APP SHELL  — dark, glass, gradient, motion. Dashboards want energy.
     · READER     — calm, high-contrast, book-like. Long prose wants quiet.
   Both are driven by the same variables so a theme switch never breaks either.
   =========================================================================== */

/* ------------------------------------------------------------------ tokens */
:root {
  --sans: "IBM Plex Sans", system-ui, -apple-system, "Segoe UI", sans-serif;
  --mono: "IBM Plex Mono", ui-monospace, SFMono-Regular, Menlo, monospace;

  --r-sm: 8px;
  --r-md: 12px;
  --r-lg: 18px;
  --r-xl: 26px;

  --wrap: 1300px;
  --col: 780px;

  --t-fast: 140ms cubic-bezier(.4, 0, .2, 1);
  --t-med: 260ms cubic-bezier(.4, 0, .2, 1);
  --t-spring: 420ms cubic-bezier(.22, 1, .36, 1);
}

/* dark is the default surface */
:root,
:root[data-theme="dark"] {
  --bg: #080A10;
  --bg-2: #0B0E16;
  --bg-3: #10141F;
  --panel: rgba(255, 255, 255, .038);
  --panel-2: rgba(255, 255, 255, .062);
  --panel-solid: #131824;
  --border: rgba(255, 255, 255, .085);
  --border-str: rgba(255, 255, 255, .16);

  --ink: #E8EDF7;
  --ink-2: #A9B5C9;
  --ink-3: #6B7893;

  --accent: #7C93FF;
  --accent-2: #35D8C6;
  --accent-ink: #0A0C12;
  --glow: rgba(124, 147, 255, .38);

  --ok: #43DD97;
  --warn: #FF7189;
  --gold: #FFC46B;
  --violet: #C08BFF;

  --shadow-1: 0 1px 2px rgba(0, 0, 0, .5);
  --shadow-2: 0 10px 34px rgba(0, 0, 0, .48);
  --shadow-3: 0 24px 70px rgba(0, 0, 0, .6);

  /* diagram palette — SVGs use classes so they re-theme automatically */
  --d-paper: #0E1420;
  --d-panel: #18202F;
  --d-rule: #35415A;
  --d-ink: #E2E8F4;
  --d-dim: #A6B4CC;
  --d-stack: #7C93FF;
  --d-heap: #C08BFF;
  --d-ok: #43DD97;
  --d-warn: #FF7189;
  --d-solid: #05070C;

  color-scheme: dark;
}

:root[data-theme="light"] {
  --bg: #E9EDF2;
  --bg-2: #EFF2F6;
  --bg-3: #FFFFFF;
  --panel: #FFFFFF;
  --panel-2: #F5F7FA;
  --panel-solid: #FFFFFF;
  --border: #D2DAE3;
  --border-str: #B6C1CE;

  --ink: #131E2B;
  --ink-2: #4A5769;
  --ink-3: #76839A;

  --accent: #3457D5;
  --accent-2: #0E9E8E;
  --accent-ink: #FFFFFF;
  --glow: rgba(52, 87, 213, .22);

  --ok: #12805F;
  --warn: #C02545;
  --gold: #A9720B;
  --violet: #7B3BAF;

  --shadow-1: 0 1px 2px rgba(24, 40, 66, .07);
  --shadow-2: 0 8px 26px rgba(24, 40, 66, .1);
  --shadow-3: 0 20px 54px rgba(24, 40, 66, .14);

  --d-paper: #FFFFFF;
  --d-panel: #F3F6FA;
  --d-rule: #C3CCD5;
  --d-ink: #131E2B;
  --d-dim: #5C6B7A;
  --d-stack: #275FA8;
  --d-heap: #7E3B8C;
  --d-ok: #1B6E55;
  --d-warn: #B3253E;
  --d-solid: #101A26;

  color-scheme: light;
}

/* ------------------------------------------------------------------- base */
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  min-height: 100vh;
}

/* Ambient gradient field — fixed so it never scrolls with content. */
body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  background:
    radial-gradient(900px 620px at 12% -8%, rgba(124, 147, 255, .16), transparent 62%),
    radial-gradient(760px 520px at 92% 2%, rgba(53, 216, 198, .11), transparent 60%),
    radial-gradient(1000px 700px at 50% 110%, rgba(192, 139, 255, .1), transparent 62%),
    linear-gradient(180deg, var(--bg) 0%, var(--bg-2) 100%);
}

:root[data-theme="light"] body::before {
  background:
    radial-gradient(900px 620px at 12% -8%, rgba(52, 87, 213, .09), transparent 62%),
    radial-gradient(760px 520px at 92% 2%, rgba(14, 158, 142, .07), transparent 60%),
    linear-gradient(180deg, var(--bg) 0%, var(--bg-2) 100%);
}

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; text-underline-offset: 3px; }

h1, h2, h3, h4 { margin: 0; font-weight: 650; letter-spacing: -.02em; line-height: 1.18; }
p { margin: 0 0 14px; }

code, kbd, samp { font-family: var(--mono); font-size: .88em; }

::selection { background: var(--accent); color: var(--accent-ink); }

/* scrollbar */
* { scrollbar-width: thin; scrollbar-color: var(--border-str) transparent; }
*::-webkit-scrollbar { width: 10px; height: 10px; }
*::-webkit-scrollbar-thumb { background: var(--border-str); border-radius: 99px; border: 3px solid transparent; background-clip: content-box; }

/* --------------------------------------------------------------- utilities */
.wrap { max-width: var(--wrap); margin: 0 auto; padding: 0 22px; }
.row { display: flex; align-items: center; gap: 12px; }
.row-b { display: flex; align-items: center; justify-content: space-between; gap: 12px; }
.col { display: flex; flex-direction: column; gap: 12px; }
.grow { flex: 1; }
.wrap-w { flex-wrap: wrap; }
.hide { display: none !important; }
.center { text-align: center; }
.mono { font-family: var(--mono); }
.dim { color: var(--ink-2); }
.mute { color: var(--ink-3); }
.tiny { font-size: 12px; }
.sm { font-size: 13.5px; }
.big { font-size: 19px; }
.tabular { font-variant-numeric: tabular-nums; }
.mt-0 { margin-top: 0; }
.mt-1 { margin-top: 10px; }
.mt-2 { margin-top: 20px; }
.mt-3 { margin-top: 32px; }
.mb-0 { margin-bottom: 0; }
.mb-1 { margin-bottom: 10px; }
.mb-2 { margin-bottom: 20px; }
.gap-s { gap: 7px; }
.gap-l { gap: 20px; }

.eyebrow {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: .18em;
  text-transform: uppercase;
  color: var(--ink-3);
  font-weight: 600;
}

/* ------------------------------------------------------------------ panels */
.panel {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--r-lg);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  box-shadow: var(--shadow-2);
  position: relative;
}

/* hairline top highlight — the detail that reads as "glass" rather than "box" */
.panel::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: 1px;
  border-radius: var(--r-lg) var(--r-lg) 0 0;
  background: linear-gradient(90deg, transparent, rgba(255, 255, 255, .22), transparent);
  pointer-events: none;
}

:root[data-theme="light"] .panel::before { display: none; }

.panel-pad { padding: 22px; }
.panel-tight { padding: 15px 17px; }

.panel-hover { transition: transform var(--t-med), border-color var(--t-med), box-shadow var(--t-med); }
.panel-hover:hover { transform: translateY(-3px); border-color: var(--border-str); box-shadow: var(--shadow-3); }

/* ----------------------------------------------------------------- buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  font-family: var(--sans);
  font-size: 14.5px;
  font-weight: 560;
  padding: 10px 18px;
  border-radius: var(--r-md);
  border: 1px solid var(--border-str);
  background: var(--panel-2);
  color: var(--ink);
  cursor: pointer;
  transition: all var(--t-fast);
  white-space: nowrap;
  line-height: 1.35;
}
.btn:hover { border-color: var(--accent); color: var(--ink); transform: translateY(-1px); }
.btn:active { transform: translateY(0); }
.btn:disabled { opacity: .42; cursor: not-allowed; transform: none; }

.btn-primary {
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  color: var(--accent-ink);
  border-color: transparent;
  box-shadow: 0 6px 22px var(--glow);
  font-weight: 620;
}
.btn-primary:hover { box-shadow: 0 10px 30px var(--glow); filter: brightness(1.06); }

.btn-ghost { background: transparent; border-color: var(--border); }
.btn-sm { padding: 6px 12px; font-size: 13px; border-radius: var(--r-sm); }
.btn-lg { padding: 13px 26px; font-size: 16px; }
.btn-block { width: 100%; }
.btn-danger { color: var(--warn); border-color: color-mix(in srgb, var(--warn) 45%, transparent); }

.icon-btn {
  width: 36px; height: 36px; padding: 0;
  border-radius: 10px; display: inline-grid; place-items: center;
  background: var(--panel-2); border: 1px solid var(--border);
  color: var(--ink-2); cursor: pointer; transition: all var(--t-fast);
}
.icon-btn:hover { color: var(--ink); border-color: var(--accent); }

/* ------------------------------------------------------------------ inputs */
.field { display: flex; flex-direction: column; gap: 6px; }
.field > label { font-size: 12.5px; font-weight: 600; color: var(--ink-2); letter-spacing: .01em; }

.input, .textarea, .select {
  width: 100%;
  font-family: var(--sans);
  font-size: 15px;
  color: var(--ink);
  background: var(--bg-3);
  border: 1px solid var(--border);
  border-radius: var(--r-md);
  padding: 11px 14px;
  transition: border-color var(--t-fast), box-shadow var(--t-fast);
}
.input:focus, .textarea:focus, .select:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--glow);
}
.input::placeholder, .textarea::placeholder { color: var(--ink-3); }
.textarea { resize: vertical; min-height: 110px; font-family: var(--mono); font-size: 13.5px; line-height: 1.6; }
.input-mono { font-family: var(--mono); font-size: 13.5px; }

/* ------------------------------------------------------------------- chips */
.chip {
  display: inline-flex; align-items: center; gap: 6px;
  font-family: var(--mono); font-size: 11px; letter-spacing: .07em; text-transform: uppercase;
  padding: 4px 9px; border-radius: 99px;
  border: 1px solid var(--border); background: var(--panel-2); color: var(--ink-2);
  font-weight: 600; white-space: nowrap;
}
.chip-ok { color: var(--ok); border-color: color-mix(in srgb, var(--ok) 42%, transparent); background: color-mix(in srgb, var(--ok) 12%, transparent); }
.chip-warn { color: var(--warn); border-color: color-mix(in srgb, var(--warn) 42%, transparent); background: color-mix(in srgb, var(--warn) 12%, transparent); }
.chip-accent { color: var(--accent); border-color: color-mix(in srgb, var(--accent) 45%, transparent); background: color-mix(in srgb, var(--accent) 12%, transparent); }
.chip-gold { color: var(--gold); border-color: color-mix(in srgb, var(--gold) 42%, transparent); background: color-mix(in srgb, var(--gold) 12%, transparent); }
.chip-violet { color: var(--violet); border-color: color-mix(in srgb, var(--violet) 42%, transparent); background: color-mix(in srgb, var(--violet) 12%, transparent); }

/* -------------------------------------------------------------- app frame */
.appbar {
  position: sticky; top: 0; z-index: 60;
  background: color-mix(in srgb, var(--bg) 82%, transparent);
  backdrop-filter: blur(18px) saturate(150%);
  -webkit-backdrop-filter: blur(18px) saturate(150%);
  border-bottom: 1px solid var(--border);
}
.appbar-in { max-width: var(--wrap); margin: 0 auto; padding: 11px 22px; display: flex; align-items: center; gap: 18px; }

.brand { display: flex; align-items: center; gap: 10px; font-weight: 700; letter-spacing: -.02em; font-size: 16px; color: var(--ink); }
.brand:hover { text-decoration: none; }
.brand-mark {
  width: 30px; height: 30px; border-radius: 9px; display: grid; place-items: center;
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  color: var(--accent-ink); font-family: var(--mono); font-weight: 700; font-size: 15px;
  box-shadow: 0 4px 16px var(--glow);
}

.nav { display: flex; gap: 3px; align-items: center; }
.nav a {
  font-size: 14px; font-weight: 520; color: var(--ink-2);
  padding: 7px 13px; border-radius: 9px; transition: all var(--t-fast);
}
.nav a:hover { color: var(--ink); background: var(--panel-2); text-decoration: none; }
.nav a.on { color: var(--ink); background: var(--panel-2); box-shadow: inset 0 0 0 1px var(--border); }

.badge-dot {
  min-width: 17px; height: 17px; padding: 0 5px; border-radius: 99px;
  background: var(--warn); color: #fff; font-size: 10.5px; font-weight: 700;
  display: inline-grid; place-items: center; font-family: var(--mono);
}

/* ------------------------------------------------------------------- stats */
.stat-row { display: grid; grid-template-columns: repeat(auto-fit, minmax(148px, 1fr)); gap: 12px; }
.stat {
  background: var(--panel); border: 1px solid var(--border); border-radius: var(--r-md);
  padding: 14px 16px; position: relative; overflow: hidden;
}
.stat-k { font-family: var(--mono); font-size: 10.5px; letter-spacing: .14em; text-transform: uppercase; color: var(--ink-3); font-weight: 600; }
.stat-v { font-size: 26px; font-weight: 680; letter-spacing: -.03em; margin-top: 3px; font-variant-numeric: tabular-nums; line-height: 1.1; }
.stat-s { font-size: 12px; color: var(--ink-3); margin-top: 2px; }
.stat-accent .stat-v { background: linear-gradient(120deg, var(--accent), var(--accent-2)); -webkit-background-clip: text; background-clip: text; color: transparent; }

/* progress bars */
.bar { height: 6px; border-radius: 99px; background: var(--panel-2); overflow: hidden; border: 1px solid var(--border); }
.bar > i { display: block; height: 100%; border-radius: 99px; background: linear-gradient(90deg, var(--accent), var(--accent-2)); transition: width var(--t-spring); }
.bar-ok > i { background: linear-gradient(90deg, var(--ok), var(--accent-2)); }
.bar-gold > i { background: linear-gradient(90deg, var(--gold), var(--warn)); }
.bar-lg { height: 10px; }

/* XP ring.
   The gradient stops are coloured from CSS, not from presentation attributes:
   `stop-color="var(--accent)"` as an ATTRIBUTE is not supported and renders black. */
#ringGrad stop:first-child { stop-color: var(--accent); }
#ringGrad stop:last-child { stop-color: var(--accent-2); }

.ring { position: relative; width: 92px; height: 92px; flex: 0 0 auto; }
.ring svg { transform: rotate(-90deg); width: 100%; height: 100%; }
.ring .track { fill: none; stroke: var(--border-str); stroke-width: 8; opacity: .55; }
.ring .fill { fill: none; stroke: url(#ringGrad); stroke-width: 8; stroke-linecap: round; transition: stroke-dashoffset var(--t-spring); }
.ring-txt { position: absolute; inset: 0; display: grid; place-content: center; text-align: center; }
.ring-txt b { font-size: 22px; font-weight: 700; letter-spacing: -.03em; display: block; line-height: 1; }
.ring-txt span { font-size: 10px; font-family: var(--mono); letter-spacing: .12em; text-transform: uppercase; color: var(--ink-3); }

/* ---------------------------------------------------------------- heatmap */
.heat { display: grid; grid-auto-flow: column; grid-template-rows: repeat(7, 1fr); gap: 3px; overflow-x: auto; padding-bottom: 4px; }
.heat i {
  width: 12px; height: 12px; border-radius: 3px; display: block;
  background: var(--panel-2); border: 1px solid var(--border); cursor: pointer;
  transition: transform var(--t-fast);
}
.heat i:hover { transform: scale(1.35); border-color: var(--accent); }
.heat i[data-l="1"] { background: color-mix(in srgb, var(--accent) 26%, transparent); }
.heat i[data-l="2"] { background: color-mix(in srgb, var(--accent) 46%, transparent); }
.heat i[data-l="3"] { background: color-mix(in srgb, var(--accent) 70%, transparent); }
.heat i[data-l="4"] { background: linear-gradient(135deg, var(--accent), var(--accent-2)); border-color: transparent; box-shadow: 0 0 10px var(--glow); }

/* ------------------------------------------------------------- week / map */
.week-card { display: grid; grid-template-columns: 62px 1fr; gap: 0; overflow: hidden; }
.week-no {
  display: grid; place-content: center; text-align: center;
  background: linear-gradient(160deg, var(--panel-2), transparent);
  border-right: 1px solid var(--border);
  font-family: var(--mono); font-weight: 700;
}
.week-no b { font-size: 20px; display: block; line-height: 1; }
.week-no span { font-size: 9px; letter-spacing: .1em; color: var(--ink-3); }
.week-body { padding: 15px 18px; min-width: 0; }

.lesson-row {
  display: grid; grid-template-columns: 34px 1fr auto; align-items: center; gap: 12px;
  padding: 10px 12px; border-radius: var(--r-md); border: 1px solid transparent;
  transition: all var(--t-fast); cursor: pointer; color: inherit;
}
.lesson-row:hover { background: var(--panel-2); border-color: var(--border); text-decoration: none; }
.lesson-row.locked { opacity: .48; cursor: not-allowed; }
.lesson-no {
  width: 30px; height: 30px; border-radius: 9px; display: grid; place-items: center;
  font-family: var(--mono); font-size: 12px; font-weight: 650;
  background: var(--panel-2); border: 1px solid var(--border); color: var(--ink-2);
}
.lesson-row.done .lesson-no { background: color-mix(in srgb, var(--ok) 20%, transparent); border-color: var(--ok); color: var(--ok); }
.lesson-row.doing .lesson-no { background: color-mix(in srgb, var(--accent) 20%, transparent); border-color: var(--accent); color: var(--accent); }
.lesson-t { font-weight: 560; font-size: 14.8px; min-width: 0; }
.lesson-sub { font-size: 12.5px; color: var(--ink-3); margin-top: 1px; }

/* --------------------------------------------------------------- toast */
.toasts { position: fixed; bottom: 22px; right: 22px; z-index: 200; display: flex; flex-direction: column; gap: 9px; align-items: flex-end; }
.toast {
  background: var(--panel-solid); border: 1px solid var(--border-str); border-radius: var(--r-md);
  padding: 12px 17px; box-shadow: var(--shadow-3); font-size: 14px; max-width: 340px;
  animation: toastIn var(--t-spring); display: flex; gap: 10px; align-items: flex-start;
}
.toast.out { animation: toastOut var(--t-med) forwards; }
.toast-ok { border-left: 3px solid var(--ok); }
.toast-err { border-left: 3px solid var(--warn); }
.toast-xp { border-left: 3px solid var(--gold); }
@keyframes toastIn { from { opacity: 0; transform: translateY(14px) scale(.96); } to { opacity: 1; transform: none; } }
@keyframes toastOut { to { opacity: 0; transform: translateX(24px); } }

/* --------------------------------------------------------------- skeleton */
.skel { background: linear-gradient(90deg, var(--panel) 25%, var(--panel-2) 50%, var(--panel) 75%); background-size: 220% 100%; animation: shimmer 1.3s infinite; border-radius: var(--r-sm); }
@keyframes shimmer { to { background-position: -220% 0; } }

/* ----------------------------------------------------------------- auth */
.auth-page { min-height: 100vh; display: grid; place-items: center; padding: 30px 18px; }
.auth-card { width: 100%; max-width: 430px; padding: 34px; }
.auth-tabs { display: grid; grid-template-columns: 1fr 1fr; gap: 4px; background: var(--panel-2); padding: 4px; border-radius: var(--r-md); margin-bottom: 22px; }
.auth-tabs button {
  padding: 9px; border-radius: 9px; border: none; background: transparent; cursor: pointer;
  font-family: var(--sans); font-size: 14px; font-weight: 570; color: var(--ink-3); transition: all var(--t-fast);
}
.auth-tabs button.on { background: var(--bg-3); color: var(--ink); box-shadow: var(--shadow-1); }

.err-msg { color: var(--warn); font-size: 13.5px; margin-top: 4px; min-height: 19px; }

/* ------------------------------------------------------------------ modal */
.modal-bg {
  position: fixed; inset: 0; z-index: 150; background: rgba(3, 5, 10, .68);
  backdrop-filter: blur(6px); display: grid; place-items: center; padding: 22px;
  animation: fadeIn var(--t-med);
}
@keyframes fadeIn { from { opacity: 0; } }
.modal { width: 100%; max-width: 560px; max-height: 86vh; overflow: auto; padding: 26px; animation: popIn var(--t-spring); }
@keyframes popIn { from { opacity: 0; transform: translateY(18px) scale(.97); } }

/* -------------------------------------------------------------- sections */
.sec-head { display: flex; align-items: baseline; gap: 12px; margin: 0 0 16px; }
.sec-head h2 { font-size: 21px; }
.sec-head .eyebrow { margin-left: auto; }

.divider { height: 1px; background: var(--border); border: 0; margin: 26px 0; }

/* ------------------------------------------------------------------- misc */
.empty-state { text-align: center; padding: 46px 22px; color: var(--ink-3); }
.empty-state b { display: block; color: var(--ink-2); font-size: 16px; margin-bottom: 6px; }

.kbd {
  font-family: var(--mono); font-size: 11px; padding: 2px 6px; border-radius: 5px;
  border: 1px solid var(--border-str); background: var(--panel-2); color: var(--ink-2);
}

.spinner {
  width: 17px; height: 17px; border-radius: 50%;
  border: 2px solid var(--border-str); border-top-color: var(--accent);
  animation: spin .7s linear infinite; display: inline-block;
}
@keyframes spin { to { transform: rotate(360deg); } }

.page-fade { animation: pageIn var(--t-spring); }
@keyframes pageIn { from { opacity: 0; transform: translateY(8px); } }

/* ------------------------------------------------------------ responsive */
@media (max-width: 900px) {
  .appbar-in { padding: 10px 15px; gap: 10px; }
  .nav a { padding: 7px 9px; font-size: 13px; }
  .wrap { padding: 0 15px; }
  .week-card { grid-template-columns: 46px 1fr; }
  .lesson-row { grid-template-columns: 30px 1fr; }
  .lesson-row > :last-child { grid-column: 1 / -1; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation-duration: .01ms !important; transition-duration: .01ms !important; }
  html { scroll-behavior: auto; }
}