/* ============================================================
   DB BEGRIFFE — engineering console
   dark blue · mid-2000s · technical
   ============================================================ */

:root {
  /* base — warm anthracite */
  --bg-deep:      #0F0F11;
  --bg:           #16171A;
  --bg-2:         #1D1F23;

  /* panels — warm graphite */
  --panel-top:    #2A2D33;
  --panel-bot:    #1B1D21;
  --panel-edge:   #3D4148;
  --panel-inset:  rgba(0, 0, 0, 0.5);
  --panel-hi:     rgba(255, 240, 220, 0.05);

  /* text — warm cream */
  --text:         #EEEAE2;
  --text-dim:     #C9C3B6;
  --muted:        #888379;
  --muted-2:      #5E5A52;

  /* accent — DB signal red + steel petrol */
  --accent:       #E63946;          /* DB-style traffic red */
  --accent-deep:  #B41E2A;
  --accent-edge:  #F26B73;
  --accent-glow:  rgba(230, 57, 70, 0.4);
  --amber:        #4FA9B8;          /* steel petrol (was amber) */
  --amber-deep:   #2A7280;

  /* rules */
  --rule:         #3A3D43;
  --rule-soft:    #25272B;
  --rule-hi:      rgba(255, 240, 220, 0.04);

  /* shadows */
  --shadow:       0 1px 0 var(--panel-hi),
                  inset 0 1px 0 var(--panel-hi),
                  0 10px 30px -10px rgba(0, 0, 0, 0.7),
                  0 24px 60px -22px rgba(0, 0, 0, 0.6);
  --shadow-sm:    0 1px 0 var(--panel-hi),
                  inset 0 1px 0 var(--panel-hi),
                  0 4px 12px -4px rgba(0, 0, 0, 0.65);
  --shadow-inset: inset 0 0 0 1px var(--rule-soft),
                  inset 0 2px 4px rgba(0, 0, 0, 0.55);

  --radius:    10px;
  --radius-sm: 6px;

  --sans:  "IBM Plex Sans", "Verdana", "Geneva", system-ui, sans-serif;
  --serif: "IBM Plex Serif", "Georgia", "Cambria", serif;
  --mono:  "IBM Plex Mono", "Consolas", "Monaco", "Courier New", monospace;
}

* { box-sizing: border-box; }
html, body {
  margin: 0; padding: 0;
  background: var(--bg-deep);
  color: var(--text);
  font-family: var(--sans);
  font-size: 12.5px;
  line-height: 1.5;
  -webkit-font-smoothing: subpixel-antialiased;
  text-rendering: optimizeLegibility;
}

/* deep page background: gradient + faint blueprint grid + vignette */
body {
  min-height: 100vh;
  background:
    radial-gradient(1200px 700px at 50% -8%, rgba(230, 57, 70, 0.10), transparent 70%),
    radial-gradient(900px 600px at 100% 100%, rgba(79, 169, 184, 0.06), transparent 60%),
    linear-gradient(180deg, #16171A 0%, #0A0B0D 100%);
  background-attachment: fixed;
  position: relative;
}
body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  background-image:
    linear-gradient(rgba(79, 169, 184, 0.025) 1px, transparent 1px),
    linear-gradient(90deg, rgba(79, 169, 184, 0.025) 1px, transparent 1px);
  background-position: -1px -1px;
  z-index: 0;
  mask-image: radial-gradient(ellipse 80% 70% at 50% 40%, black 30%, transparent 90%);
  -webkit-mask-image: radial-gradient(ellipse 80% 70% at 50% 40%, black 30%, transparent 90%);
}
body::after {
  /* subtle horizontal scanlines */
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  background-image: repeating-linear-gradient(
    0deg,
    rgba(255, 255, 255, 0.012) 0,
    rgba(255, 255, 255, 0.012) 1px,
    transparent 1px,
    transparent 3px
  );
  z-index: 1;
  mix-blend-mode: overlay;
}

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

button { font-family: inherit; cursor: pointer; }
input, textarea, select, button { font-family: inherit; color: var(--text); }

em, i { font-style: italic; color: var(--accent); }
strong { font-weight: 700; color: var(--text); }

kbd {
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: 0;
  background: linear-gradient(180deg, var(--panel-top) 0%, var(--panel-bot) 100%);
  border: 1px solid var(--panel-edge);
  box-shadow:
    inset 0 1px 0 var(--panel-hi),
    0 1px 0 #050507;
  padding: 1px 5px 2px;
  border-radius: var(--radius-sm);
  color: var(--text-dim);
  font-weight: 500;
  text-transform: uppercase;
}

.app {
  max-width: 1280px;
  margin: 0 auto;
  padding:
    max(24px, env(safe-area-inset-top))
    max(32px, env(safe-area-inset-right))
    max(32px, env(safe-area-inset-bottom))
    max(32px, env(safe-area-inset-left));
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  min-height: 100dvh;
  gap: 0;
  position: relative;
  z-index: 2;
}

/* ============================================================
   HEADER — engineering console title bar
   ============================================================ */
.site-header {
  display: flex;
  justify-content: space-between;
  align-items: stretch;
  gap: 24px;
  padding: 16px 22px;
  background: linear-gradient(180deg, var(--panel-top) 0%, var(--panel-bot) 100%);
  border: 1px solid var(--panel-edge);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  position: relative;
}
.site-header::before {
  /* corner crosshair detail */
  content: "";
  position: absolute;
  top: 6px; right: 8px;
  width: 8px; height: 8px;
  background:
    linear-gradient(var(--accent), var(--accent)) center / 100% 1px no-repeat,
    linear-gradient(var(--accent), var(--accent)) center / 1px 100% no-repeat;
  opacity: 0.6;
}

.brand { display: flex; gap: 14px; align-items: center; }
.brand-mark {
  width: 44px;
  height: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--accent-edge);
  background: rgba(0, 0, 0, 0.35);
  border: 1px solid var(--panel-edge);
  border-radius: var(--radius-sm);
  box-shadow: inset 0 1px 0 rgba(0,0,0,0.4), 0 1px 0 var(--panel-hi);
  flex-shrink: 0;
  text-shadow: 0 0 12px var(--accent-glow);
  filter: drop-shadow(0 0 6px var(--accent-glow));
}
.brand-num {
  font-family: var(--mono);
  font-size: 38px;
  line-height: 1;
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--accent);
  text-shadow: 0 0 12px var(--accent-glow);
  padding: 4px 10px;
  border: 1px solid var(--panel-edge);
  background: linear-gradient(180deg, var(--panel-top) 0%, var(--panel-bot) 100%);
  border-radius: var(--radius-sm);
  box-shadow: inset 0 1px 0 rgba(0,0,0,0.4), 0 1px 0 #050507;
}
.brand-text { display: flex; flex-direction: column; gap: 1px; }
.brand-eyebrow {
  font-family: var(--sans);
  font-size: 10px;
  letter-spacing: 0.24em;
  font-weight: 700;
  color: var(--accent-edge);
  text-transform: uppercase;
}
.brand-title {
  font-family: var(--serif);
  font-size: 26px;
  font-weight: 400;
  line-height: 1.1;
  margin: 0;
  color: var(--text);
  letter-spacing: 0.005em;
}
.brand-title em { font-style: italic; color: var(--accent); }

.header-actions {
  display: flex;
  align-items: center;
  gap: 8px;
}

/* 2000s segmented tabs */
.mode-switch {
  display: flex;
  background: rgba(0, 0, 0, 0.35);
  border: 1px solid var(--rule-soft);
  border-radius: var(--radius-sm);
  padding: 2px;
  gap: 0;
  box-shadow: inset 0 1px 2px rgba(0, 0, 0, 0.45);
}
.mode-btn {
  font-family: var(--sans);
  font-size: 10.5px;
  letter-spacing: 0.16em;
  font-weight: 700;
  text-transform: uppercase;
  padding: 7px 14px;
  border: 1px solid transparent;
  background: transparent;
  color: var(--muted);
  border-radius: var(--radius-sm);
  transition: all 0.15s ease;
}
.mode-btn:hover { color: var(--text-dim); }
.mode-btn.is-active {
  background: linear-gradient(180deg, var(--accent) 0%, var(--accent-deep) 100%);
  color: white;
  border-color: var(--accent-edge);
  box-shadow:
    inset 0 1px 0 rgba(255,255,255,0.25),
    inset 0 -1px 0 rgba(0,0,0,0.2),
    0 1px 0 rgba(0,0,0,0.4);
  text-shadow: 0 -1px 0 rgba(0,0,0,0.2);
}

.icon-btn {
  font-family: var(--sans);
  font-size: 11px;
  letter-spacing: 0.12em;
  font-weight: 700;
  text-transform: uppercase;
  padding: 7px 14px;
  display: inline-flex;
  align-items: center;
  gap: 7px;
  white-space: nowrap;
  background: linear-gradient(180deg, var(--amber) 0%, var(--amber-deep) 100%);
  color: #062B33;
  border: 1px solid #1F5963;
  border-radius: var(--radius-sm);
  text-shadow: 0 1px 0 rgba(255, 255, 255, 0.25);
  box-shadow:
    inset 0 1px 0 rgba(255,255,255,0.4),
    inset 0 -1px 0 rgba(0,0,0,0.15),
    0 1px 0 rgba(0,0,0,0.45);
  transition: all 0.12s ease;
}
.icon-btn:hover {
  background: linear-gradient(180deg, #6FBFCB 0%, #3D8896 100%);
}
.icon-btn:active {
  background: linear-gradient(180deg, var(--amber-deep) 0%, var(--amber) 100%);
  box-shadow: inset 0 1px 3px rgba(0,0,0,0.3);
}
.icon-btn.ghost {
  background: linear-gradient(180deg, var(--panel-top) 0%, var(--panel-bot) 100%);
  color: var(--text-dim);
  border-color: var(--panel-edge);
  padding: 7px 9px;
  text-shadow: 0 -1px 0 rgba(0,0,0,0.3);
}
.icon-btn.ghost:hover { color: var(--accent-edge); border-color: var(--accent-deep); }

/* ============================================================
   CATEGORY BAR — register/filter bar
   ============================================================ */
.cat-bar {
  display: flex;
  gap: 0;
  margin-top: 12px;
  padding: 0 6px;
  flex-wrap: wrap;
  background: linear-gradient(180deg, rgba(0,0,0,0.3) 0%, rgba(0,0,0,0.15) 100%);
  border: 1px solid var(--rule-soft);
  border-radius: var(--radius);
  box-shadow: inset 0 1px 0 var(--panel-hi);
}
.cat-pill {
  font-family: var(--sans);
  font-size: 10.5px;
  letter-spacing: 0.14em;
  font-weight: 700;
  padding: 10px 16px;
  white-space: nowrap;
  background: transparent;
  border: none;
  border-right: 1px solid var(--rule-soft);
  color: var(--muted);
  border-radius: 0;
  text-transform: uppercase;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  transition: all 0.15s ease;
}
.cat-pill:last-of-type { border-right: none; }
.cat-pill:hover { color: var(--text); background: rgba(230, 57, 70, 0.05); }
.cat-pill.is-active {
  color: var(--accent);
  background: rgba(230, 57, 70, 0.10);
  box-shadow:
    inset 0 -2px 0 var(--accent),
    inset 0 1px 0 var(--panel-hi);
}
.cat-count {
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: 0;
  text-transform: none;
  color: var(--muted-2);
  font-weight: 400;
  padding: 1px 5px;
  border: 1px solid var(--rule-soft);
  background: rgba(0, 0, 0, 0.3);
  border-radius: var(--radius-sm);
}
.cat-pill.is-active .cat-count {
  color: var(--accent-edge);
  border-color: var(--accent-deep);
  background: rgba(230, 57, 70, 0.08);
}

/* ============================================================
   STAGE
   ============================================================ */
.stage {
  flex: 1;
  padding: 24px 0 20px;
  display: flex;
  flex-direction: column;
}

.empty {
  text-align: center;
  padding: 80px 20px;
  color: var(--muted);
  font-family: var(--serif);
  font-size: 17px;
}
.empty em { color: var(--accent); }

/* ============================================================
   KARTEIKARTEN
   ============================================================ */
.karteikarten {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 22px;
}

.kk-meta {
  width: 100%;
  max-width: 760px;
  display: flex;
  align-items: center;
  gap: 20px;
  padding: 10px 14px;
  background: linear-gradient(180deg, rgba(0,0,0,0.35) 0%, rgba(0,0,0,0.15) 100%);
  border: 1px solid var(--rule-soft);
  border-radius: var(--radius-sm);
  box-shadow: inset 0 1px 0 var(--panel-hi), inset 0 -1px 0 rgba(0,0,0,0.4);
}
.kk-progress { flex: 1; display: flex; align-items: center; gap: 14px; }
.kk-progress-track {
  flex: 1;
  height: 6px;
  background: linear-gradient(180deg, #0A0B0D 0%, #16171A 100%);
  border: 1px solid var(--rule-soft);
  border-radius: var(--radius-sm);
  overflow: hidden;
  box-shadow: inset 0 1px 2px rgba(0,0,0,0.6);
}
.kk-progress-fill {
  height: 100%;
  background:
    linear-gradient(180deg, var(--accent-edge) 0%, var(--accent) 50%, var(--accent-deep) 100%);
  box-shadow:
    inset 0 1px 0 rgba(255,255,255,0.3),
    0 0 8px var(--accent-glow);
  border-right: 1px solid var(--accent-edge);
  transition: width 0.4s cubic-bezier(0.4, 0.0, 0.2, 1);
}
.kk-progress-label {
  font-family: var(--mono);
  display: inline-flex;
  align-items: baseline;
  gap: 2px;
  color: var(--text-dim);
}
.kk-idx { font-size: 18px; color: var(--accent-edge); font-weight: 700; text-shadow: 0 0 6px var(--accent-glow); }
.kk-of { font-size: 13px; color: var(--muted); }
.kk-known {
  font-family: var(--sans);
  font-size: 10.5px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--muted);
  font-weight: 700;
  display: inline-flex;
  align-items: baseline;
  gap: 6px;
}
.kk-known-num {
  font-family: var(--mono);
  font-size: 16px;
  color: var(--amber);
  font-style: normal;
  font-weight: 700;
}

/* card stage */
.card-wrap {
  display: flex;
  align-items: center;
  gap: 16px;
  width: 100%;
  max-width: 900px;
  justify-content: center;
}
.nav-arrow {
  width: 42px;
  height: 42px;
  border-radius: 50%;
  border: 1px solid var(--panel-edge);
  background: linear-gradient(180deg, var(--panel-top) 0%, var(--panel-bot) 100%);
  color: var(--text-dim);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  box-shadow:
    inset 0 1px 0 var(--panel-hi),
    0 2px 4px rgba(0,0,0,0.4);
  transition: all 0.15s ease;
}
.nav-arrow:hover {
  color: var(--accent-edge);
  border-color: var(--accent-deep);
  box-shadow:
    inset 0 1px 0 var(--panel-hi),
    0 0 12px var(--accent-glow);
}
.nav-arrow:active { box-shadow: inset 0 1px 4px rgba(0,0,0,0.45); }

.card-anim {
  width: 100%;
  max-width: 640px;
  flex: 1;
  perspective: 1800px;
  animation: cardEnter 0.32s cubic-bezier(0.2, 0.7, 0.2, 1);
}
.card-anim.dir-prev { animation: cardEnterPrev 0.32s cubic-bezier(0.2, 0.7, 0.2, 1); }
@keyframes cardEnter { from { opacity: 0; } to { opacity: 1; } }
@keyframes cardEnterPrev { from { opacity: 0; } to { opacity: 1; } }

.flashcard {
  width: 100%;
  aspect-ratio: 1.6 / 1;
  position: relative;
  cursor: pointer;
  transform-style: preserve-3d;
  transition: transform 0.6s cubic-bezier(0.4, 0.0, 0.2, 1);
}
.flashcard.is-flipped { transform: rotateY(180deg); }

.card-face {
  position: absolute;
  inset: 0;
  background:
    linear-gradient(180deg, var(--panel-top) 0%, var(--panel-bot) 100%);
  border: 1px solid var(--panel-edge);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 0;
  display: flex;
  flex-direction: column;
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
  transition: opacity 0s linear 0.3s;
  overflow: hidden;
}
.card-face::before {
  /* faint blueprint grid inside the card */
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(230, 57, 70, 0.05) 1px, transparent 1px),
    linear-gradient(90deg, rgba(230, 57, 70, 0.05) 1px, transparent 1px);
  background-size: 24px 24px;
  pointer-events: none;
  mask-image: radial-gradient(ellipse 70% 50% at 50% 60%, black, transparent 95%);
  -webkit-mask-image: radial-gradient(ellipse 70% 50% at 50% 60%, black, transparent 95%);
}
.card-face::after {
  /* gloss highlight at top */
  content: "";
  position: absolute;
  left: 0; right: 0; top: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent 0%, rgba(255,255,255,0.18) 50%, transparent 100%);
}
.card-front {}
.card-back {
  transform: rotateY(180deg);
  opacity: 0;
}
.flashcard.is-flipped .card-front { opacity: 0; }
.flashcard.is-flipped .card-back  { opacity: 1; }

.card-corner-top {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
  font-family: var(--sans);
  font-size: 10px;
  letter-spacing: 0.2em;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--accent-edge);
  padding: 12px 22px;
  background: linear-gradient(180deg, rgba(0,0,0,0.25) 0%, transparent 100%);
  border-bottom: 1px solid var(--rule);
  position: relative;
  z-index: 2;
  white-space: nowrap;
}
.card-cat {
  color: var(--accent-edge);
  overflow: hidden;
  text-overflow: ellipsis;
  min-width: 0;
}
.card-side-label { color: var(--muted); font-weight: 700; }
.card-edit {
  background: transparent;
  border: none;
  color: var(--muted);
  padding: 4px 6px;
  border-radius: var(--radius-sm);
  display: inline-flex;
  transition: color 0.15s, background 0.15s;
}
.card-edit:hover { color: var(--accent-edge); background: rgba(230,57,70,0.1); }

.card-body {
  flex: 1;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: flex-start;
  padding: 24px 32px;
  position: relative;
  z-index: 1;
  overflow-y: auto;
  scrollbar-width: thin;
}
.card-body::-webkit-scrollbar { width: 6px; }
.card-body::-webkit-scrollbar-track { background: transparent; }
.card-body::-webkit-scrollbar-thumb { background: var(--rule); border-radius: 4px; }
.card-body.has-overflow {
  justify-content: flex-start;
}

.card-de {
  font-family: var(--serif);
  font-size: 40px;
  line-height: 1.08;
  font-weight: 400;
  letter-spacing: -0.005em;
  color: var(--text);
  text-wrap: balance;
  text-shadow: 0 1px 0 rgba(0,0,0,0.3);
}
.card-en {
  font-family: var(--serif);
  font-size: 22px;
  font-style: italic;
  color: var(--accent);
  margin-bottom: 14px;
  text-shadow: 0 0 12px var(--accent-glow);
}
.card-def {
  font-family: var(--sans);
  font-size: 13.5px;
  line-height: 1.55;
  color: var(--text-dim);
  max-width: 56ch;
  text-wrap: pretty;
}

.card-corner-bot {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--muted);
  padding: 10px 22px;
  border-top: 1px solid var(--rule);
  background: linear-gradient(180deg, transparent 0%, rgba(0,0,0,0.25) 100%);
  position: relative;
  z-index: 2;
}
.card-id { color: var(--muted); font-family: var(--mono); }
.card-hint { color: var(--muted); font-family: var(--sans); letter-spacing: 0.12em; font-weight: 700; }
.card-hint .dot { color: var(--accent); margin-left: 4px; }
.card-known-mark {
  color: var(--amber);
  font-family: var(--sans);
  text-transform: uppercase;
  font-size: 10px;
  letter-spacing: 0.14em;
  font-weight: 700;
}

/* ---------- kk-controls ---------- */
.kk-controls {
  display: flex;
  gap: 8px;
  align-items: center;
  flex-wrap: wrap;
  justify-content: center;
}
.ctrl-btn {
  font-family: var(--sans);
  font-size: 11px;
  letter-spacing: 0.12em;
  font-weight: 700;
  text-transform: uppercase;
  padding: 7px 14px;
  display: inline-flex;
  align-items: center;
  gap: 7px;
  white-space: nowrap;
  background: linear-gradient(180deg, var(--panel-top) 0%, var(--panel-bot) 100%);
  color: var(--text-dim);
  border: 1px solid var(--panel-edge);
  border-radius: var(--radius-sm);
  text-shadow: 0 -1px 0 rgba(0,0,0,0.3);
  box-shadow:
    inset 0 1px 0 var(--panel-hi),
    inset 0 -1px 0 rgba(0,0,0,0.2),
    0 1px 0 rgba(0,0,0,0.4);
  transition: all 0.12s ease;
}
.ctrl-btn:hover {
  color: var(--accent-edge);
  border-color: var(--accent-deep);
}
.ctrl-btn:active {
  box-shadow: inset 0 1px 3px rgba(0,0,0,0.4);
}
.ctrl-btn.primary {
  background: linear-gradient(180deg, var(--accent) 0%, var(--accent-deep) 100%);
  color: white;
  border-color: var(--accent-edge);
  text-shadow: 0 -1px 0 rgba(0,0,0,0.25);
}
.ctrl-btn.primary:hover {
  background: linear-gradient(180deg, var(--accent-edge) 0%, var(--accent) 100%);
}
.ctrl-btn.is-known {
  background: linear-gradient(180deg, var(--amber) 0%, var(--amber-deep) 100%);
  border-color: #1F5963;
  color: #062B33;
  text-shadow: 0 1px 0 rgba(255,255,255,0.25);
}
.ctrl-btn kbd { margin-left: 4px; }

.ctrl-toggle {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  white-space: nowrap;
  font-family: var(--sans);
  font-size: 11px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  font-weight: 700;
  color: var(--text-dim);
  cursor: pointer;
  padding: 7px 14px;
  background: linear-gradient(180deg, var(--panel-top) 0%, var(--panel-bot) 100%);
  border: 1px solid var(--panel-edge);
  border-radius: var(--radius-sm);
  text-shadow: 0 -1px 0 rgba(0,0,0,0.3);
  box-shadow:
    inset 0 1px 0 var(--panel-hi),
    0 1px 0 rgba(0,0,0,0.4);
}
.ctrl-toggle input { accent-color: var(--accent); margin: 0; }
.ctrl-toggle.is-on {
  color: var(--accent-edge);
  border-color: var(--accent-deep);
  background: linear-gradient(180deg, #5A1F25 0%, #2A0E11 100%);
}

.kk-hint {
  font-family: var(--sans);
  font-size: 11px;
  color: var(--muted);
  text-align: center;
  letter-spacing: 0.06em;
}
.kk-hint em { font-style: normal; color: var(--accent-edge); font-weight: 700; }

/* ============================================================
   MEMORY MODE
   ============================================================ */
.memory { display: flex; flex-direction: column; gap: 18px; }
.mem-top {
  display: flex;
  gap: 24px;
  align-items: center;
  padding: 14px 22px;
  background: linear-gradient(180deg, var(--panel-top) 0%, var(--panel-bot) 100%);
  border: 1px solid var(--panel-edge);
  border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
  flex-wrap: wrap;
  position: relative;
}
.mem-stat { display: flex; flex-direction: column; gap: 2px; min-width: 72px; }
.mem-stat-label {
  font-family: var(--sans);
  font-size: 9px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--muted);
  font-weight: 700;
}
.mem-stat-val {
  font-family: var(--mono);
  font-size: 20px;
  color: var(--accent-edge);
  font-weight: 700;
  text-shadow: 0 0 8px var(--accent-glow);
}
.mem-controls { margin-left: auto; display: flex; gap: 8px; align-items: center; }
.mem-pair-pick {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--sans);
  font-size: 10px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--muted);
  font-weight: 700;
}
.mem-pair-pick select {
  font-family: var(--mono);
  font-size: 13px;
  padding: 5px 8px;
  background: rgba(0,0,0,0.35);
  border: 1px solid var(--rule);
  border-radius: var(--radius-sm);
  color: var(--text);
  font-weight: 700;
}

.mem-board {
  display: grid;
  gap: 8px;
  grid-template-columns: repeat(var(--cols, 6), 1fr);
}
.mem-board.cols-4 { --cols: 4; }
.mem-board.cols-5 { --cols: 5; }
.mem-board.cols-6 { --cols: 6; }

.mem-tile {
  aspect-ratio: 1.15 / 1;
  perspective: 1000px;
  background: transparent;
  border: none;
  padding: 0;
  position: relative;
}
.mem-tile-inner {
  position: absolute;
  inset: 0;
  transform-style: preserve-3d;
  transition: transform 0.5s cubic-bezier(0.4, 0.0, 0.2, 1);
}
.mem-tile.is-open .mem-tile-inner,
.mem-tile.is-matched .mem-tile-inner { transform: rotateY(180deg); }

.mem-tile-back, .mem-tile-front {
  position: absolute;
  inset: 0;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 12px;
  border: 1px solid var(--panel-edge);
  box-shadow: var(--shadow-sm);
  overflow: hidden;
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
  transition: opacity 0s linear 0.25s;
}
.mem-tile-back {
  background:
    repeating-linear-gradient(45deg,
      rgba(230, 57, 70, 0.06) 0 6px,
      transparent 6px 12px),
    linear-gradient(180deg, var(--panel-top) 0%, var(--panel-bot) 100%);
}
.mem-tile-back::after {
  content: "";
  position: absolute;
  inset: 6px;
  border: 1px dashed rgba(230, 57, 70, 0.18);
  border-radius: var(--radius-sm);
}
.mem-tile-mark {
  font-family: var(--mono);
  font-size: 22px;
  font-style: normal;
  color: var(--accent);
  letter-spacing: 0.1em;
  font-weight: 700;
  text-shadow: 0 0 10px var(--accent-glow);
  position: relative;
  z-index: 1;
}
.mem-tile-front {
  background: linear-gradient(180deg, var(--panel-top) 0%, var(--panel-bot) 100%);
  transform: rotateY(180deg);
  opacity: 0;
}
.mem-tile.is-open .mem-tile-back,
.mem-tile.is-matched .mem-tile-back { opacity: 0; }
.mem-tile.is-open .mem-tile-front,
.mem-tile.is-matched .mem-tile-front { opacity: 1; }

.mem-tile.is-matched .mem-tile-front {
  background: linear-gradient(180deg, #5A1F25 0%, #2A0E11 100%);
  border-color: var(--accent);
  box-shadow:
    inset 0 1px 0 rgba(255,255,255,0.1),
    0 0 14px var(--accent-glow);
}
.mem-tile.is-matched .mem-de { color: var(--accent-edge); }
.mem-tile.is-matched .mem-en { color: var(--accent-edge); }

.mem-de {
  font-family: var(--serif);
  font-size: 14px;
  line-height: 1.2;
  color: var(--text);
  font-weight: 400;
  text-wrap: balance;
}
.mem-en {
  font-family: var(--serif);
  font-size: 13px;
  line-height: 1.2;
  color: var(--accent);
  font-style: italic;
  text-wrap: balance;
}

.mem-tile:disabled { cursor: default; }
.mem-tile:not(.is-open):not(.is-matched):hover .mem-tile-back {
  background:
    repeating-linear-gradient(45deg,
      rgba(230, 57, 70, 0.12) 0 6px,
      transparent 6px 12px),
    linear-gradient(180deg, #4F2026 0%, #2A0E11 100%);
  border-color: var(--accent-deep);
}

.mem-done {
  position: fixed;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(15, 15, 17, 0.75);
  backdrop-filter: blur(4px);
  z-index: 100;
  animation: fadeIn 0.3s ease;
}
.mem-done-card {
  background: linear-gradient(180deg, var(--panel-top) 0%, var(--panel-bot) 100%);
  padding: 40px 56px;
  border-radius: var(--radius);
  box-shadow: var(--shadow), 0 0 40px var(--accent-glow);
  text-align: center;
  max-width: 480px;
  border: 1px solid var(--accent-deep);
}
.mem-done-eyebrow {
  font-family: var(--sans);
  font-size: 10px;
  letter-spacing: 0.3em;
  color: var(--accent-edge);
  font-weight: 700;
  margin-bottom: 8px;
}
.mem-done-card h2 {
  font-family: var(--serif);
  font-size: 36px;
  font-weight: 400;
  margin: 0 0 10px;
  line-height: 1.05;
  color: var(--text);
}
.mem-done-card h2 em { font-style: italic; color: var(--accent); }
.mem-done-card p {
  font-family: var(--mono);
  color: var(--text-dim);
  font-size: 14px;
  margin: 0 0 24px;
}

/* ============================================================
   LISTE / GLOSSAR
   ============================================================ */
.liste { display: flex; flex-direction: column; gap: 28px; }
.liste-toolbar { display: flex; gap: 12px; }
.liste-search {
  flex: 1;
  font-family: var(--sans);
  font-size: 14px;
  padding: 10px 16px;
  background: rgba(0,0,0,0.35);
  border: 1px solid var(--rule);
  border-radius: var(--radius-sm);
  color: var(--text);
  outline: none;
  transition: all 0.15s;
  box-shadow: inset 0 1px 3px rgba(0,0,0,0.45);
}
.liste-search:focus {
  border-color: var(--accent-deep);
  box-shadow: inset 0 1px 3px rgba(0,0,0,0.45), 0 0 8px var(--accent-glow);
}
.liste-search::placeholder { color: var(--muted); }

.liste-section {
  display: flex;
  flex-direction: column;
  background: linear-gradient(180deg, rgba(0,0,0,0.2) 0%, transparent 100%);
  border: 1px solid var(--rule-soft);
  border-radius: var(--radius);
}
.liste-cat {
  font-family: var(--sans);
  font-size: 10.5px;
  letter-spacing: 0.22em;
  font-weight: 700;
  color: var(--accent-edge);
  margin: 0;
  padding: 12px 18px;
  background: linear-gradient(180deg, rgba(230,57,70,0.08) 0%, transparent 100%);
  border-bottom: 1px solid var(--rule);
  text-shadow: 0 1px 0 rgba(0,0,0,0.3);
}

.rule { height: 1px; background: var(--rule); border: none; }
.rule.thin { background: var(--rule-soft); }

.liste-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 0;
}
.liste-card {
  padding: 14px 18px;
  position: relative;
  border-bottom: 1px solid var(--rule-soft);
  border-right: 1px solid var(--rule-soft);
}
.liste-card:nth-child(2n) { border-right: none; }
.liste-card:hover { background: rgba(230, 57, 70, 0.04); }
.liste-head {
  font-family: var(--serif);
  font-size: 15px;
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 6px;
  margin-bottom: 3px;
}
.liste-de { font-weight: 600; color: var(--text); }
.liste-mid { color: var(--muted-2); }
.liste-en { color: var(--accent); font-style: italic; font-size: 13px; }
.liste-def {
  font-family: var(--sans);
  font-size: 12.5px;
  line-height: 1.5;
  color: var(--text-dim);
  margin: 0;
}
.liste-actions {
  position: absolute;
  top: 12px;
  right: 12px;
  opacity: 0;
  transition: opacity 0.15s;
}
.liste-card:hover .liste-actions { opacity: 1; }

/* ============================================================
   FOOTER
   ============================================================ */
.site-footer {
  margin-top: 18px;
  padding: 10px 16px;
  background: linear-gradient(180deg, var(--panel-top) 0%, var(--panel-bot) 100%);
  border: 1px solid var(--panel-edge);
  border-radius: var(--radius-sm);
  box-shadow: var(--shadow-sm);
}
.site-footer .rule { display: none; }
.footer-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-family: var(--mono);
  font-size: 10.5px;
  letter-spacing: 0.08em;
  color: var(--muted);
}
.foot-meta { letter-spacing: 0.1em; text-transform: uppercase; font-weight: 700; white-space: nowrap; }
.link-btn { white-space: nowrap; }
.foot-meta:first-child { color: var(--accent-edge); }

.link-btn {
  font-family: var(--sans);
  font-size: 10.5px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.14em;
  background: transparent;
  border: none;
  color: var(--accent-edge);
  padding: 4px 6px;
  transition: color 0.15s;
}
.link-btn:hover { color: var(--amber); text-decoration: underline; text-underline-offset: 3px; }
.link-btn.danger { color: #E25C5C; }

/* ============================================================
   MODAL
   ============================================================ */
.modal-scrim {
  position: fixed;
  inset: 0;
  background: rgba(5, 11, 22, 0.65);
  backdrop-filter: blur(3px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 200;
  padding: 24px;
  animation: fadeIn 0.2s ease;
}
@keyframes fadeIn { from { opacity: 0 } to { opacity: 1 } }

.modal {
  background: linear-gradient(180deg, var(--panel-top) 0%, var(--panel-bot) 100%);
  border-radius: var(--radius);
  box-shadow: var(--shadow), 0 0 40px rgba(230,57,70,0.15);
  width: 100%;
  max-width: 540px;
  padding: 0;
  display: flex;
  flex-direction: column;
  border: 1px solid var(--panel-edge);
  animation: modalIn 0.28s cubic-bezier(0.2, 0.7, 0.2, 1);
  max-height: calc(100vh - 48px);
  overflow-y: auto;
}
@keyframes modalIn {
  from { transform: translateY(16px); opacity: 0; }
  to { transform: translateY(0); opacity: 1; }
}

.modal-head {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 18px 24px 14px;
  background: linear-gradient(180deg, rgba(0,0,0,0.25) 0%, transparent 100%);
  border-bottom: 1px solid var(--rule);
}
.modal-eyebrow {
  font-family: var(--sans);
  font-size: 10px;
  letter-spacing: 0.24em;
  font-weight: 700;
  color: var(--accent-edge);
  text-transform: uppercase;
}
.modal h2 {
  font-family: var(--serif);
  font-size: 24px;
  font-weight: 400;
  line-height: 1.1;
  margin: 0;
  color: var(--text);
  text-wrap: balance;
}
.modal h2 em { font-style: italic; color: var(--accent); }

.field {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 0 24px;
  margin-top: 14px;
}
.field > span {
  font-family: var(--sans);
  font-size: 10px;
  letter-spacing: 0.18em;
  font-weight: 700;
  color: var(--accent-edge);
  text-transform: uppercase;
}
.field input, .field textarea, .field select {
  font-family: var(--sans);
  font-size: 13.5px;
  padding: 8px 12px;
  background: rgba(0,0,0,0.4);
  border: 1px solid var(--rule);
  border-radius: var(--radius-sm);
  outline: none;
  transition: all 0.15s;
  color: var(--text);
  box-shadow: inset 0 1px 3px rgba(0,0,0,0.45);
}
.field input:focus, .field textarea:focus, .field select:focus {
  border-color: var(--accent-deep);
  box-shadow: inset 0 1px 3px rgba(0,0,0,0.45), 0 0 6px var(--accent-glow);
}
.field textarea { resize: vertical; min-height: 60px; line-height: 1.5; }

.modal-foot {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 10px;
  padding: 14px 24px 18px;
  border-top: 1px solid var(--rule);
  margin-top: 18px;
  background: linear-gradient(180deg, transparent 0%, rgba(0,0,0,0.25) 100%);
}
.modal-foot-right { display: flex; gap: 8px; }

.modal.info p {
  font-family: var(--sans);
  font-size: 13px;
  line-height: 1.6;
  margin: 0;
  padding: 0 24px;
  margin-top: 14px;
  color: var(--text-dim);
}
.modal.info p .muted { color: var(--muted); font-style: italic; }
.info-shortcuts {
  margin: 14px 24px 0;
  background: rgba(0,0,0,0.35);
  padding: 14px 16px;
  border-left: 2px solid var(--accent);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
}
.info-eyebrow {
  font-family: var(--sans);
  font-size: 10px;
  letter-spacing: 0.22em;
  color: var(--accent-edge);
  font-weight: 700;
  margin-bottom: 10px;
}
.info-shortcuts ul {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 8px;
  font-family: var(--sans);
  font-size: 12px;
  color: var(--text-dim);
}
.info-shortcuts li { display: flex; align-items: center; gap: 8px; }

/* ============================================================
   RESPONSIVE — tablet + phone (iOS / Android friendly)
   ============================================================ */

/* Prevent horizontal overflow on small screens */
html, body { overflow-x: hidden; max-width: 100vw; }

/* Larger touch targets on touch devices */
@media (hover: none) and (pointer: coarse) {
  .liste-actions { opacity: 1 !important; }
  .ctrl-btn, .icon-btn, .mode-btn, .ctrl-toggle, .nav-arrow, .cat-pill, .liste-card {
    -webkit-tap-highlight-color: rgba(230, 57, 70, 0.18);
  }
}

@media (max-width: 960px) {
  .app {
    padding:
      max(16px, env(safe-area-inset-top))
      max(16px, env(safe-area-inset-right))
      max(20px, env(safe-area-inset-bottom))
      max(16px, env(safe-area-inset-left));
  }
  .site-header {
    flex-direction: column;
    gap: 14px;
    align-items: stretch;
    padding: 14px 16px;
  }
  .header-actions {
    flex-wrap: wrap;
    justify-content: space-between;
    gap: 8px;
  }
  .mode-switch { flex: 1; }
  .mode-btn { flex: 1; text-align: center; }
  .brand-title { font-size: 22px; }
  .brand-num { font-size: 32px; padding: 4px 8px; }
  .brand-mark { width: 40px; height: 40px; }
  .card-de { font-size: 30px; }
  .card-en { font-size: 19px; }
  .card-body { padding: 22px 24px; }
  .liste-grid { grid-template-columns: 1fr; }
  .liste-card { border-right: none; }
  .mem-board.cols-6 { --cols: 4; }
  .mem-board.cols-5 { --cols: 4; }
  .nav-arrow { width: 44px; height: 44px; }
  .card-wrap { gap: 8px; }
  .stage { padding: 20px 0 16px; }
}

@media (max-width: 640px) {
  .site-header { padding: 12px 14px; }
  .brand { gap: 12px; }
  .brand-mark { width: 38px; height: 38px; }
  .brand-eyebrow { font-size: 9px; letter-spacing: 0.18em; }
  .brand-title { font-size: 19px; }

  /* Tabs: keep horizontal but allow scroll if needed */
  .header-actions { gap: 8px; }
  .mode-switch { width: 100%; }
  .mode-btn { padding: 10px 8px; font-size: 10px; }
  .icon-btn { padding: 10px 12px; font-size: 10.5px; }
  .icon-btn.ghost { padding: 10px 11px; }

  /* Cards adapt to narrower, taller form factor */
  .card-anim { max-width: 100%; }
  .flashcard {
    aspect-ratio: 4 / 5;
  }
  .card-de { font-size: 24px; }
  .card-en { font-size: 17px; margin-bottom: 10px; }
  .card-def { font-size: 13px; }
  .card-body { padding: 18px 20px; }
  .card-corner-top, .card-corner-bot { padding: 10px 14px; }
  .card-corner-top { font-size: 9.5px; gap: 10px; }
  .card-corner-bot { font-size: 9.5px; }

  /* Nav arrows: as 44px circle outside card */
  .nav-arrow { width: 40px; height: 40px; }
  .card-wrap { gap: 4px; }

  /* Category bar: horizontal scroll */
  .cat-bar {
    flex-wrap: nowrap;
    overflow-x: auto;
    overflow-y: hidden;
    margin: 12px -16px 0;
    padding: 0 16px;
    border-radius: 0;
    border-left: none;
    border-right: none;
    scrollbar-width: none;
    -webkit-overflow-scrolling: touch;
  }
  .cat-bar::-webkit-scrollbar { display: none; }
  .cat-pill {
    padding: 12px 14px;
    font-size: 10px;
    flex-shrink: 0;
  }

  /* Progress meta */
  .kk-meta { padding: 10px 12px; gap: 14px; flex-wrap: wrap; }
  .kk-known { font-size: 9.5px; }
  .kk-idx { font-size: 16px; }

  /* Controls: full row, larger taps */
  .kk-controls { gap: 6px; width: 100%; }
  .ctrl-btn {
    padding: 11px 12px;
    font-size: 10.5px;
    min-height: 44px;
    flex: 1;
    justify-content: center;
  }
  .ctrl-btn kbd { display: none; }
  .ctrl-toggle { padding: 11px 14px; min-height: 44px; }
  .kk-hint { font-size: 10px; padding: 0 8px; }

  /* Memory */
  .mem-top { gap: 12px; padding: 12px 14px; }
  .mem-stat { min-width: 56px; }
  .mem-stat-val { font-size: 16px; }
  .mem-stat-label { font-size: 8.5px; }
  .mem-controls { width: 100%; margin-left: 0; justify-content: space-between; }
  .mem-board.cols-6, .mem-board.cols-5, .mem-board.cols-4 { --cols: 3; }
  .mem-de, .mem-en { font-size: 11.5px; }
  .mem-tile-mark { font-size: 14px; }
  .mem-tile-back, .mem-tile-front { padding: 8px; }

  /* Glossar */
  .liste-cat { font-size: 10px; padding: 10px 14px; }
  .liste-card { padding: 12px 14px; }

  /* Footer */
  .site-footer { padding: 10px 12px; }
  .footer-row { font-size: 9.5px; gap: 10px; flex-wrap: wrap; }
  .foot-meta { letter-spacing: 0.08em; }

  /* Modal: full width, bottom-anchored */
  .modal-scrim { padding: 0; align-items: flex-end; }
  .modal {
    max-width: 100%;
    width: 100%;
    border-radius: 18px 18px 0 0;
    max-height: 92vh;
    max-height: 92dvh;
    padding-bottom: env(safe-area-inset-bottom);
  }
  .modal-head { padding: 18px 18px 12px; }
  .modal h2 { font-size: 22px; }
  .field { padding: 0 18px; }
  .field input, .field textarea, .field select { font-size: 16px; /* prevents iOS zoom on focus */ padding: 12px 14px; min-height: 44px; }
  .field textarea { min-height: 80px; }
  .modal-foot { padding: 14px 18px 18px; }
  .modal.info p { padding: 0 18px; margin-top: 12px; font-size: 14px; }
  .info-shortcuts { margin: 12px 18px 0; padding: 12px 14px; }
  .info-shortcuts ul { grid-template-columns: 1fr; font-size: 13px; }

  /* Search input */
  .liste-search { font-size: 16px; min-height: 44px; }
  .liste-toolbar { padding: 0; }
}

@media (max-width: 380px) {
  .brand-title { font-size: 17px; }
  .mode-btn { padding: 9px 6px; font-size: 9.5px; letter-spacing: 0.1em; }
  .icon-btn span { display: none; }
  .icon-btn { padding: 10px; }
  .card-de { font-size: 21px; }
  .card-en { font-size: 15px; }
  .card-def { font-size: 12.5px; }
  .ctrl-btn { font-size: 10px; padding: 11px 10px; }
}