:root {
  --bg: #0f1115;
  --bg-elev: #161a22;
  --bg-elev-2: #1d2230;
  --border: #262c3a;
  --text: #e7eaf0;
  --text-dim: #8b94a7;
  --accent: #ff5a36;
  --accent-2: #ffae00;
  --good: #3ddc97;
  --danger: #ef476f;
  --chip: #232938;
  --shadow: 0 6px 24px rgba(0,0,0,.35);
  --safe-bottom: env(safe-area-inset-bottom, 0px);
  --safe-top: env(safe-area-inset-top, 0px);
  --bottom-nav-h: 64px;
}

* { box-sizing: border-box; -webkit-tap-highlight-color: transparent; }

html, body {
  margin: 0;
  padding: 0;
  background: linear-gradient(180deg, #0c0e13 0%, #11141b 100%);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  min-height: 100vh;
  -webkit-text-size-adjust: 100%;
  overscroll-behavior-y: contain;
}

/* ===== MOBILE-FIRST BASE ===== */

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: .65rem .9rem;
  padding-top: calc(.65rem + var(--safe-top));
  background: rgba(15,17,21,.92);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 50;
}

.brand { display: flex; align-items: center; gap: .5rem; }
.brand .logo {
  font-size: 1.5rem;
  filter: drop-shadow(0 0 6px rgba(255,90,54,.5));
}
.brand h1 {
  margin: 0;
  font-size: 1.05rem;
  letter-spacing: .04em;
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.tabs-top { display: none; }

.unit-toggle label {
  display: inline-flex;
  align-items: center;
  gap: .4rem;
  font-size: .85rem;
  color: var(--text-dim);
  cursor: pointer;
  min-height: 32px;
}
.unit-toggle input {
  accent-color: var(--accent);
  width: 18px; height: 18px;
}

/* Bottom tab bar (mobile) */
.tabs-bottom {
  position: fixed;
  bottom: 0; left: 0; right: 0;
  display: flex;
  background: rgba(15,17,21,.95);
  backdrop-filter: blur(14px);
  border-top: 1px solid var(--border);
  padding-bottom: var(--safe-bottom);
  z-index: 60;
  box-shadow: 0 -4px 16px rgba(0,0,0,.4);
}
.tab-bottom {
  flex: 1;
  background: transparent;
  border: 0;
  color: var(--text-dim);
  font-size: .65rem;
  font-weight: 500;
  padding: .55rem .25rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: .15rem;
  cursor: pointer;
  min-height: var(--bottom-nav-h);
  position: relative;
  transition: color .15s;
}
.tab-bottom svg {
  width: 22px;
  height: 22px;
  stroke: currentColor;
}
.tab-bottom.active {
  color: var(--accent-2);
}
.tab-bottom.active::before {
  content: '';
  position: absolute;
  top: 0;
  left: 30%; right: 30%;
  height: 2px;
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
  border-radius: 0 0 2px 2px;
}
.tab-bottom.tab-primary {
  color: var(--text);
}
.tab-bottom.tab-primary svg {
  width: 38px; height: 38px;
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  border-radius: 50%;
  padding: 8px;
  stroke: #1a1109;
  margin-top: -14px;
  box-shadow: 0 4px 14px rgba(255,90,54,.4);
}
.tab-bottom.tab-primary.active::before { display: none; }

main {
  max-width: 1200px;
  margin: 0 auto;
  padding: .9rem .9rem calc(var(--bottom-nav-h) + var(--safe-bottom) + 1rem);
}

.view { display: none; }
.view.active { display: block; }

.grid { display: grid; gap: .75rem; margin-bottom: .75rem; }
.grid-2 { grid-template-columns: 1fr; }
.grid-3 { grid-template-columns: 1fr 1fr; }
.grid-3 .stat:first-child { grid-column: 1 / -1; }

.card {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 1rem;
  box-shadow: var(--shadow);
  margin-bottom: .75rem;
}
.card h2 {
  margin: 0 0 .8rem 0;
  font-size: 1rem;
  letter-spacing: .02em;
}

.stat { text-align: left; }
.stat-label {
  color: var(--text-dim);
  font-size: .72rem;
  text-transform: uppercase;
  letter-spacing: .08em;
}
.stat-value {
  font-size: 1.7rem;
  font-weight: 700;
  margin-top: .2rem;
  background: linear-gradient(90deg, #fff, var(--accent-2));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  line-height: 1.1;
}

.muscle-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: .6rem;
}
.muscle-card {
  background: var(--bg-elev-2);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: .7rem;
  text-align: center;
  cursor: pointer;
  transition: transform .15s ease, border-color .15s;
  min-height: 44px;
}
.muscle-card:active { transform: scale(.97); }
.muscle-card svg { width: 100%; height: auto; max-height: 90px; }
.muscle-card .name {
  margin-top: .35rem;
  font-weight: 600;
  text-transform: capitalize;
  font-size: .95rem;
}
.muscle-card .count {
  font-size: .75rem;
  color: var(--text-dim);
}

.filter-bar {
  display: flex;
  gap: .4rem;
  overflow-x: auto;
  margin-bottom: .85rem;
  padding-bottom: .25rem;
  scrollbar-width: none;
  -webkit-overflow-scrolling: touch;
}
.filter-bar::-webkit-scrollbar { display: none; }
.chip {
  background: var(--chip);
  border: 1px solid var(--border);
  color: var(--text-dim);
  padding: .5rem 1rem;
  border-radius: 999px;
  cursor: pointer;
  font-size: .88rem;
  white-space: nowrap;
  flex-shrink: 0;
  min-height: 36px;
}
.chip.active {
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
  color: #1a1109;
  border-color: transparent;
  font-weight: 600;
}

.exercise-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: .75rem;
}
.exercise-card {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: 12px;
  overflow: hidden;
  box-shadow: var(--shadow);
  display: flex;
  flex-direction: column;
  transition: transform .15s, border-color .15s;
}
.exercise-card:active { transform: scale(.98); }
.exercise-visual {
  background: radial-gradient(circle at center, #232938 0%, #161a22 70%);
  padding: .5rem;
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 130px;
  overflow: hidden;
}
.exercise-visual .ex-svg svg {
  width: 100px;
  height: 100px;
}
.exercise-img {
  max-width: 100%;
  max-height: 150px;
  object-fit: contain;
  border-radius: 6px;
  filter: drop-shadow(0 2px 8px rgba(0, 0, 0, 0.5));
  background: #fff;
  padding: 3px;
}
.exercise-body { padding: .65rem .7rem .8rem; }
.exercise-name {
  font-weight: 600;
  font-size: .9rem;
  line-height: 1.25;
}
.exercise-group {
  display: inline-block;
  margin-top: .3rem;
  padding: .1rem .45rem;
  border-radius: 999px;
  background: var(--bg-elev-2);
  color: var(--accent-2);
  font-size: .65rem;
  text-transform: uppercase;
  letter-spacing: .08em;
}
.exercise-desc {
  margin-top: .45rem;
  color: var(--text-dim);
  font-size: .75rem;
  line-height: 1.4;
}
.best-set {
  margin-top: .45rem;
  font-size: .75rem;
  color: var(--good);
}

/* Forms */
.row {
  display: flex;
  gap: .6rem;
  flex-direction: column;
}
.field { display: flex; flex-direction: column; gap: .3rem; }
.field.grow { flex: 1; }
.field label {
  font-size: .72rem;
  color: var(--text-dim);
  text-transform: uppercase;
  letter-spacing: .06em;
}

input, select, textarea {
  background: var(--bg-elev-2);
  border: 1px solid var(--border);
  color: var(--text);
  padding: .7rem .8rem;
  border-radius: 10px;
  font-size: 16px; /* prevent iOS zoom */
  font-family: inherit;
  outline: none;
  transition: border-color .15s;
  min-height: 44px;
  width: 100%;
}
input:focus, select:focus, textarea:focus {
  border-color: var(--accent);
}
textarea { resize: vertical; min-height: 96px; }
input[type=date] { min-height: 44px; }

.btn {
  background: var(--bg-elev-2);
  color: var(--text);
  border: 1px solid var(--border);
  padding: .75rem 1.1rem;
  border-radius: 10px;
  cursor: pointer;
  font-weight: 500;
  font-size: .95rem;
  transition: transform .1s ease, border-color .15s;
  min-height: 44px;
  width: 100%;
}
.btn:active { transform: scale(.97); }
.btn.primary {
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
  color: #1a1109;
  border-color: transparent;
  font-weight: 700;
}
.btn.ghost {
  background: transparent;
  border-color: var(--good);
  color: var(--good);
}
.btn.danger {
  background: transparent;
  border-color: var(--danger);
  color: var(--danger);
}
.btn.sm {
  padding: .45rem .7rem;
  font-size: .82rem;
  min-height: 36px;
  width: auto;
}

.session-head {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1rem;
  gap: .5rem;
}
.session-head h2 { flex: 1; margin: 0; }
.session-head .btn { width: auto; }

.session-exercises {
  display: flex;
  flex-direction: column;
  gap: .75rem;
  margin: 1rem 0;
}
.session-ex {
  background: var(--bg-elev-2);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: .85rem;
}
.session-ex-head {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: .7rem;
  gap: .5rem;
}
.session-ex-head .name {
  font-weight: 600;
  display: flex;
  align-items: center;
  gap: .5rem;
  font-size: .92rem;
  min-width: 0;
}
.session-ex-head .name svg { width: 26px; height: 26px; flex-shrink: 0; }
.session-ex-head .name span {
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.sets-table {
  width: 100%;
  border-collapse: collapse;
  font-size: .88rem;
}
.sets-table th, .sets-table td {
  padding: .35rem .25rem;
  text-align: left;
  border-bottom: 1px solid var(--border);
}
.sets-table th:first-child, .sets-table td:first-child {
  width: 22px;
  color: var(--text-dim);
}
.sets-table th:last-child, .sets-table td:last-child {
  width: 40px;
  text-align: right;
}
.sets-table th {
  color: var(--text-dim);
  font-weight: 500;
  font-size: .68rem;
  text-transform: uppercase;
  letter-spacing: .06em;
}
.sets-table input[type=number] {
  width: 100%;
  padding: .5rem .55rem;
  min-height: 40px;
  text-align: center;
  font-weight: 600;
  font-variant-numeric: tabular-nums;
}
.sets-table .btn.sm {
  padding: .3rem .55rem;
  min-height: 32px;
}
.add-set { margin-top: .55rem; }
.add-set .btn { width: 100%; }

.list {
  display: flex;
  flex-direction: column;
  gap: .55rem;
}
.list-item {
  background: var(--bg-elev-2);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: .75rem .9rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: .75rem;
}
.list-item > div:first-child { min-width: 0; flex: 1; }
.list-item .title {
  font-weight: 600;
  font-size: .95rem;
  overflow: hidden;
  text-overflow: ellipsis;
}
.list-item .meta {
  color: var(--text-dim);
  font-size: .78rem;
  margin-top: .15rem;
  overflow: hidden;
  text-overflow: ellipsis;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
}
.list-item .actions { display: flex; gap: .4rem; flex-shrink: 0; }

.empty {
  color: var(--text-dim);
  text-align: center;
  padding: 1.4rem;
  font-style: italic;
}

.session-detail {
  background: var(--bg-elev-2);
  border-radius: 8px;
  padding: .7rem .9rem;
  margin-top: .4rem;
  font-size: .85rem;
}
.session-detail .ex-line {
  padding: .25rem 0;
  border-bottom: 1px dashed var(--border);
}
.session-detail .ex-line:last-child { border-bottom: none; }
.session-detail .ex-name { font-weight: 600; color: var(--accent-2); }

.toast {
  position: fixed;
  bottom: calc(var(--bottom-nav-h) + var(--safe-bottom) + 1rem);
  left: 50%;
  transform: translateX(-50%) translateY(20px);
  background: var(--bg-elev-2);
  border: 1px solid var(--accent);
  color: var(--text);
  padding: .65rem 1.1rem;
  border-radius: 999px;
  font-size: .9rem;
  opacity: 0;
  transition: all .25s ease;
  pointer-events: none;
  z-index: 100;
  box-shadow: var(--shadow);
}
.toast.show {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

canvas {
  width: 100% !important;
  background: var(--bg-elev-2);
  border-radius: 8px;
  padding: .5rem;
}

.attribution {
  margin-top: 1.5rem;
  text-align: center;
  font-size: .75rem;
  color: var(--text-dim);
}
.attribution a {
  color: var(--accent-2);
  text-decoration: none;
}
.attribution a:hover { text-decoration: underline; }

/* ===== TABLET (>= 600px) ===== */
@media (min-width: 600px) {
  main { padding: 1.25rem 1.25rem calc(var(--bottom-nav-h) + var(--safe-bottom) + 1.5rem); }
  .grid-3 { grid-template-columns: repeat(3, 1fr); }
  .grid-3 .stat:first-child { grid-column: auto; }
  .muscle-grid { grid-template-columns: repeat(5, 1fr); }
  .muscle-card svg { max-height: 110px; }
  .exercise-grid { grid-template-columns: repeat(auto-fill, minmax(220px, 1fr)); }
  .exercise-name { font-size: 1rem; }
  .exercise-desc { font-size: .82rem; }
  .exercise-img { max-height: 180px; }
  .row { flex-direction: row; align-items: flex-end; flex-wrap: wrap; }
  .field.grow { min-width: 180px; }
  .btn { width: auto; }
  .add-set .btn { width: auto; }
}

/* ===== DESKTOP (>= 900px) ===== */
@media (min-width: 900px) {
  .topbar {
    padding: .9rem 1.5rem;
    padding-top: calc(.9rem + var(--safe-top));
    gap: 1.5rem;
  }
  .brand h1 { font-size: 1.15rem; }
  .brand .logo { font-size: 1.6rem; }
  .tabs-top {
    display: flex;
    gap: .25rem;
    flex: 1;
    flex-wrap: wrap;
  }
  .tabs-top .tab {
    background: transparent;
    border: 1px solid transparent;
    color: var(--text-dim);
    padding: .5rem .85rem;
    border-radius: 8px;
    cursor: pointer;
    font-weight: 500;
    font-size: .92rem;
    transition: all .15s ease;
    min-height: 40px;
  }
  .tabs-top .tab:hover { color: var(--text); background: var(--bg-elev); }
  .tabs-top .tab.active {
    color: var(--text);
    background: var(--bg-elev-2);
    border-color: var(--border);
    box-shadow: inset 0 -2px 0 var(--accent);
  }
  .tabs-bottom { display: none; }
  main {
    padding: 1.5rem;
  }
  .grid-2 { grid-template-columns: 1fr 1fr; }
  .grid { gap: 1rem; margin-bottom: 1rem; }
  .card { padding: 1.1rem 1.2rem; margin-bottom: 1rem; }
  .card h2 { font-size: 1.05rem; }
  .stat-value { font-size: 2rem; }
  .toast { bottom: 1.5rem; }
}