/* ═══════════════════════════════════════════════════════════════
   POST-OP EXERCISE TRACKER — Global Styles
   Design: Refined medical utility
   Mobile-first. Tested breakpoints: 320px → 2560px
   ═══════════════════════════════════════════════════════════════ */

/* ── Design Tokens ──────────────────────────────────────────── */
:root {
  /* Colour palette */
  --clr-primary:        #0d4f6e;   /* deep teal — brand, header */
  --clr-primary-mid:    #1a6b8a;   /* mid teal — hover states   */
  --clr-primary-light:  #e8f4f8;   /* pale teal — card bg tint  */
  --clr-accent:         #2a9d8f;   /* green-teal — success      */
  --clr-accent-light:   #e6f5f3;   /* pale accent — logged card */
  --clr-warn:           #e07b39;   /* amber — offline, pending  */
  --clr-warn-light:     #fdf1e7;
  --clr-error:          #c0392b;
  --clr-error-light:    #fdecea;

  /* Frequency badge colours */
  --clr-daily:          #1a6b8a;
  --clr-daily-bg:       #e0f0f6;
  --clr-alt1:           #6b4f9e;   /* purple */
  --clr-alt1-bg:        #f0ebfb;
  --clr-alt2:           #b7600a;   /* amber-brown */
  --clr-alt2-bg:        #fdf0e3;

  /* Neutral scale */
  --clr-bg:             #f5f7f8;   /* page background             */
  --clr-surface:        #ffffff;   /* card / panel surface        */
  --clr-border:         #d4dde3;   /* subtle borders              */
  --clr-border-strong:  #b0bec8;
  --clr-text-primary:   #1a2a33;   /* headings, labels            */
  --clr-text-body:      #334351;   /* body copy                   */
  --clr-text-muted:     #637585;   /* supporting text             */
  --clr-text-disabled:  #a0b0bc;

  /* Typography */
  --font-base: 'Segoe UI', 'Helvetica Neue', Arial, sans-serif;

  /* Spacing scale (4px base) */
  --sp-1:  4px;
  --sp-2:  8px;
  --sp-3:  12px;
  --sp-4:  16px;
  --sp-5:  20px;
  --sp-6:  24px;
  --sp-8:  32px;
  --sp-10: 40px;

  /* Radii */
  --radius-sm:  6px;
  --radius-md:  10px;
  --radius-lg:  16px;
  --radius-xl:  22px;

  /* Shadows */
  --shadow-card: 0 1px 4px rgba(13,79,110,0.08), 0 2px 12px rgba(13,79,110,0.06);
  --shadow-nav:  0 -2px 12px rgba(13,79,110,0.10);

  /* Layout */
  --nav-height:    64px;
  --header-height: 88px;
  --content-max:   640px;          /* max width for content column */

  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-mid:  250ms ease;
}

/* ── Reset & Base ───────────────────────────────────────────── */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-base);
  font-size: 1rem;
  line-height: 1.5;
  color: var(--clr-text-body);
  background: var(--clr-bg);
  min-height: 100dvh;
  min-height: 100vh;   /* fallback */
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

button {
  font-family: inherit;
  cursor: pointer;
  border: none;
  background: none;
}

button:disabled {
  cursor: not-allowed;
}

select, input {
  font-family: inherit;
  font-size: 1rem;
}

/* ── Screen Shell ───────────────────────────────────────────── */
/*
  Layout model:
    body
      └── .screen (full viewport height, flex column)
            ├── .app-header   (fixed height)
            ├── .offline-banner (conditionally shown)
            ├── .screen-body  (flex-grow: 1, scrollable)
      └── .bottom-nav (fixed, bottom)
      └── #toast (fixed overlay)
*/

.screen {
  display: flex;
  flex-direction: column;
  min-height: 100dvh;
  min-height: 100vh;
  padding-bottom: var(--nav-height);
}

/* ── App Header ─────────────────────────────────────────────── */
.app-header {
  background: var(--clr-primary);
  color: #ffffff;
  padding: var(--sp-4) var(--sp-5);
  padding-top: max(var(--sp-4), env(safe-area-inset-top));
  flex-shrink: 0;
}

.header-meta {
  display: flex;
  align-items: center;
  gap: var(--sp-3);
  margin-bottom: var(--sp-2);
}

.header-title-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.app-title {
  font-size: 1.375rem;
  font-weight: 700;
  letter-spacing: -0.01em;
  color: #ffffff;
}

.hdr-date {
  font-size: 0.8125rem;
  color: rgba(255,255,255,0.75);
  font-weight: 400;
}

/* Recovery day badge */
.day-badge {
  display: inline-flex;
  align-items: center;
  background: rgba(255,255,255,0.18);
  color: #ffffff;
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  padding: 2px var(--sp-2);
  border-radius: var(--radius-xl);
  border: 1px solid rgba(255,255,255,0.25);
}

/* Completion badge — shown in header */
.completion-badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  flex-shrink: 0;
  transition: var(--transition-mid);
}

.completion-badge--pending {
  color: rgba(255,255,255,0.55);
}

.completion-badge--done {
  background: var(--clr-accent);
  color: #ffffff;
  box-shadow: 0 0 0 3px rgba(42,157,143,0.35);
}

.completion-badge--done svg circle {
  display: none;
}

/* ── Offline Banner ─────────────────────────────────────────── */
.offline-banner {
  display: flex;
  align-items: center;
  gap: var(--sp-2);
  background: var(--clr-warn-light);
  color: var(--clr-warn);
  font-size: 0.8125rem;
  font-weight: 500;
  padding: var(--sp-2) var(--sp-5);
  border-bottom: 1px solid #f0c090;
  flex-shrink: 0;
}

/* ── Screen Body ────────────────────────────────────────────── */
.screen-body {
  flex: 1;
  overflow-y: auto;
  overflow-x: hidden;
  padding: var(--sp-5);
  max-width: var(--content-max);
  width: 100%;
  margin: 0 auto;
  /* Smooth momentum scrolling on iOS */
  -webkit-overflow-scrolling: touch;
}

.screen-body--flush {
  padding: 0;
  max-width: 100%;
}

/* ── Time-of-Day Selector ───────────────────────────────────── */
.tod-bar {
  display: flex;
  align-items: center;
  gap: var(--sp-3);
  background: var(--clr-surface);
  border: 1px solid var(--clr-border);
  border-radius: var(--radius-md);
  padding: var(--sp-3) var(--sp-4);
  margin-bottom: var(--sp-4);
  box-shadow: var(--shadow-card);
}

.tod-label {
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--clr-text-muted);
  white-space: nowrap;
  flex-shrink: 0;
}

.tod-select {
  flex: 1;
  border: none;
  background: transparent;
  color: var(--clr-text-primary);
  font-weight: 600;
  font-size: 0.9375rem;
  padding: 0;
  appearance: none;
  -webkit-appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='8' viewBox='0 0 12 8'%3E%3Cpath d='M1 1l5 5 5-5' stroke='%23637585' stroke-width='1.8' stroke-linecap='round' stroke-linejoin='round' fill='none'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 0 center;
  padding-right: var(--sp-5);
  cursor: pointer;
  min-height: 44px;
}

.tod-select:focus {
  outline: 2px solid var(--clr-primary);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}

/* ── Exercise List ──────────────────────────────────────────── */
.exercise-list {
  display: flex;
  flex-direction: column;
  gap: var(--sp-3);
}

/* ── Exercise Card ──────────────────────────────────────────── */
.exercise-card {
  background: var(--clr-surface);
  border: 1.5px solid var(--clr-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-card);
  overflow: hidden;
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.exercise-card:focus-within {
  border-color: var(--clr-primary-mid);
}

/* Logged state */
.exercise-card--logged {
  border-color: var(--clr-accent);
  background: var(--clr-accent-light);
}

/* Card Header (always visible, tappable) */
.card-header {
  display: flex;
  align-items: center;
  gap: var(--sp-3);
  padding: var(--sp-4);
  cursor: pointer;
  min-height: 64px;
  user-select: none;
  -webkit-tap-highlight-color: transparent;
  transition: background var(--transition-fast);
}

.card-header:hover {
  background: var(--clr-primary-light);
}

.exercise-card--logged .card-header:hover {
  background: rgba(42,157,143,0.08);
}

/* Expand/Collapse chevron */
.card-chevron {
  flex-shrink: 0;
  width: 20px;
  height: 20px;
  color: var(--clr-text-muted);
  transition: transform var(--transition-mid);
  margin-left: auto;
}

.exercise-card--open .card-chevron {
  transform: rotate(180deg);
}

/* Exercise name and badges */
.card-title-group {
  flex: 1;
  min-width: 0;
}

.card-exercise-name {
  font-size: 1rem;
  font-weight: 700;
  color: var(--clr-text-primary);
  line-height: 1.3;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.exercise-card--logged .card-exercise-name {
  color: #166252;
}

.card-badges {
  display: flex;
  align-items: center;
  gap: var(--sp-2);
  margin-top: var(--sp-1);
  flex-wrap: wrap;
}

/* Frequency badge */
.freq-badge {
  font-size: 0.6875rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  padding: 2px 7px;
  border-radius: var(--radius-xl);
}

.freq-badge--daily {
  color: var(--clr-daily);
  background: var(--clr-daily-bg);
}

.freq-badge--alt1 {
  color: var(--clr-alt1);
  background: var(--clr-alt1-bg);
}

.freq-badge--alt2 {
  color: var(--clr-alt2);
  background: var(--clr-alt2-bg);
}

.freq-badge--shelved {
  color: #888;
  background: #eee;
  font-style: italic;
  opacity: 0.75;
}

/* Progression badge */
.prog-badge {
  font-size: 0.6875rem;
  font-weight: 600;
  color: var(--clr-text-muted);
  background: #eef2f5;
  padding: 2px 7px;
  border-radius: var(--radius-xl);
}

/* Logged summary (replaces badges when logged) */
.logged-summary {
  font-size: 0.8125rem;
  font-weight: 600;
  color: #166252;
  background: rgba(42,157,143,0.12);
  padding: 2px 8px;
  border-radius: var(--radius-xl);
}

/* Logged checkmark icon */
.card-check {
  flex-shrink: 0;
  width: 28px;
  height: 28px;
  background: var(--clr-accent);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #ffffff;
}

/* Card Body (collapsible) */
.card-body {
  display: none;
  padding: 0 var(--sp-4) var(--sp-4);
  border-top: 1px solid var(--clr-border);
}

.exercise-card--logged .card-body {
  border-top-color: rgba(42,157,143,0.2);
}

.exercise-card--open .card-body {
  display: block;
}

/* Exercise description text */
.card-description {
  font-size: 0.875rem;
  color: var(--clr-text-body);
  line-height: 1.6;
  margin: var(--sp-3) 0 var(--sp-4);
  padding: var(--sp-3);
  background: var(--clr-bg);
  border-radius: var(--radius-sm);
  border-left: 3px solid var(--clr-primary-mid);
}

/* Log form inside card */
.log-form {
  display: flex;
  flex-direction: column;
  gap: var(--sp-3);
}

.log-inputs {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--sp-3);
}

.input-group {
  display: flex;
  flex-direction: column;
  gap: var(--sp-1);
}

.input-label {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--clr-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.input-field {
  border: 1.5px solid var(--clr-border);
  border-radius: var(--radius-sm);
  padding: var(--sp-2) var(--sp-3);
  font-size: 1.0625rem;
  font-weight: 600;
  color: var(--clr-text-primary);
  background: var(--clr-surface);
  min-height: 44px;
  text-align: center;
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.input-field:focus {
  outline: none;
  border-color: var(--clr-primary);
  box-shadow: 0 0 0 3px rgba(13,79,110,0.12);
}

.input-field::-webkit-inner-spin-button,
.input-field::-webkit-outer-spin-button {
  opacity: 1;
}

.input-unit {
  font-size: 0.75rem;
  color: var(--clr-text-muted);
  text-align: center;
  margin-top: 2px;
}

/* Per-card time-of-day selector */
.tod-group {
  display: flex;
  flex-direction: column;
  gap: var(--sp-1);
}

.tod-select {
  border: 1.5px solid var(--clr-border);
  border-radius: var(--radius-sm);
  padding: var(--sp-2) var(--sp-3);
  font-size: 0.9375rem;
  font-weight: 500;
  color: var(--clr-text-primary);
  background: var(--clr-surface);
  min-height: 44px;
  width: 100%;
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
  cursor: pointer;
}

.tod-select:focus {
  outline: none;
  border-color: var(--clr-primary);
  box-shadow: 0 0 0 3px rgba(13,79,110,0.12);
}

/* Log / Update button */
.btn-log {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--sp-2);
  width: 100%;
  min-height: 48px;
  background: var(--clr-primary);
  color: #ffffff;
  font-size: 0.9375rem;
  font-weight: 700;
  border-radius: var(--radius-md);
  transition: background var(--transition-fast), transform var(--transition-fast);
  -webkit-tap-highlight-color: transparent;
}

.btn-log:hover:not(:disabled) {
  background: var(--clr-primary-mid);
}

.btn-log:active:not(:disabled) {
  transform: scale(0.98);
}

.btn-log:disabled {
  background: var(--clr-text-disabled);
}

.btn-log--update {
  background: var(--clr-accent);
}

.btn-log--update:hover:not(:disabled) {
  background: #238a7d;
}

/* ── Add Session Button ─────────────────────────────────────── */
.btn-add {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 100%;
  min-height: 48px;
  background: transparent;
  color: var(--clr-primary);
  font-size: 0.9375rem;
  font-weight: 600;
  border: 2px solid var(--clr-primary);
  border-radius: var(--radius-md);
  transition: background var(--transition-fast), transform var(--transition-fast);
  -webkit-tap-highlight-color: transparent;
  margin-top: var(--sp-2);
}

.btn-add:hover:not(:disabled) {
  background: rgba(13, 79, 110, 0.06);
}

.btn-add:active:not(:disabled) {
  transform: scale(0.98);
}

.btn-add:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

/* ── Progression Screen Cards ───────────────────────────────── */
.progression-card {
  background: var(--clr-surface);
  border: 1.5px solid var(--clr-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-card);
  padding: var(--sp-4);
  display: flex;
  flex-direction: column;
  gap: var(--sp-3);
}

.prog-card-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: var(--sp-3);
}

.prog-card-name {
  font-size: 1rem;
  font-weight: 700;
  color: var(--clr-text-primary);
  line-height: 1.3;
}

.prog-level-chip {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  font-size: 0.8125rem;
  font-weight: 700;
  color: var(--clr-primary);
  background: var(--clr-primary-light);
  padding: 3px var(--sp-3);
  border-radius: var(--radius-xl);
  white-space: nowrap;
  flex-shrink: 0;
}

.prog-level-chip--maxed {
  color: var(--clr-accent);
  background: var(--clr-accent-light);
}

.prog-description {
  font-size: 0.875rem;
  color: var(--clr-text-body);
  line-height: 1.6;
  padding: var(--sp-3);
  background: var(--clr-bg);
  border-radius: var(--radius-sm);
  border-left: 3px solid var(--clr-primary-mid);
}

.btn-advance {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--sp-2);
  width: 100%;
  min-height: 48px;
  background: var(--clr-primary);
  color: #ffffff;
  font-size: 0.9375rem;
  font-weight: 700;
  border-radius: var(--radius-md);
  transition: background var(--transition-fast), transform var(--transition-fast);
  -webkit-tap-highlight-color: transparent;
}

.btn-advance:hover:not(:disabled) {
  background: var(--clr-primary-mid);
}

.btn-advance:active:not(:disabled) {
  transform: scale(0.98);
}

.btn-advance:disabled {
  background: var(--clr-bg);
  color: var(--clr-text-disabled);
  border: 1.5px solid var(--clr-border);
}

/* Progression card: name + frequency badge stacked vertically */
.prog-name-group {
  display: flex;
  flex-direction: column;
  gap: var(--sp-1);
  min-width: 0;
}

/* Action button row: Revert (left) + Advance (right) */
.prog-card-actions {
  display: grid;
  grid-template-columns: 1fr 2fr;
  gap: var(--sp-2);
}

/* Revert button — outlined secondary style */
.btn-revert {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--sp-1);
  width: 100%;
  min-height: 48px;
  background: transparent;
  color: var(--clr-text-muted);
  font-size: 0.875rem;
  font-weight: 600;
  border: 1.5px solid var(--clr-border);
  border-radius: var(--radius-md);
  transition: background var(--transition-fast), color var(--transition-fast),
              border-color var(--transition-fast);
  -webkit-tap-highlight-color: transparent;
}

.btn-revert:hover:not(:disabled) {
  background: var(--clr-bg);
  color: var(--clr-text-primary);
  border-color: var(--clr-text-muted);
}

.btn-revert:active:not(:disabled) {
  transform: scale(0.98);
}

.btn-revert:disabled {
  color: var(--clr-text-disabled);
  border-color: var(--clr-border);
  cursor: not-allowed;
}

/* ── Bottom Navigation ──────────────────────────────────────── */
.bottom-nav {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  height: var(--nav-height);
  padding-bottom: env(safe-area-inset-bottom);
  background: var(--clr-surface);
  box-shadow: var(--shadow-nav);
  display: flex;
  align-items: stretch;
  z-index: 100;
  border-top: 1px solid var(--clr-border);
}

.nav-btn {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 3px;
  color: var(--clr-text-muted);
  font-size: 0.6875rem;
  font-weight: 600;
  letter-spacing: 0.02em;
  transition: color var(--transition-fast);
  min-height: 44px;
  -webkit-tap-highlight-color: transparent;
  border-radius: 0;
  padding-bottom: 2px;
}

.nav-btn:hover {
  color: var(--clr-primary);
}

.nav-btn--active {
  color: var(--clr-primary);
}

.nav-icon {
  width: 24px;
  height: 24px;
  stroke-width: 1.8;
  transition: transform var(--transition-fast);
}

.nav-btn--active .nav-icon {
  stroke-width: 2.2;
}

.nav-btn:active .nav-icon {
  transform: scale(0.88);
}

.nav-label {
  line-height: 1;
}

/* ── Toast Notification ─────────────────────────────────────── */
.toast {
  position: fixed;
  bottom: calc(var(--nav-height) + var(--sp-4));
  left: 50%;
  transform: translateX(-50%) translateY(8px);
  background: var(--clr-text-primary);
  color: #ffffff;
  font-size: 0.875rem;
  font-weight: 600;
  padding: var(--sp-3) var(--sp-5);
  border-radius: var(--radius-xl);
  box-shadow: 0 4px 20px rgba(0,0,0,0.22);
  white-space: nowrap;
  pointer-events: none;
  opacity: 0;
  transition: opacity 200ms ease, transform 200ms ease;
  z-index: 200;
  max-width: calc(100vw - var(--sp-8));
}

.toast--visible {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

.toast--success { background: var(--clr-accent); }
.toast--error   { background: var(--clr-error); }
.toast--warn    { background: var(--clr-warn); }

/* ── Loading Screen ─────────────────────────────────────────── */
.screen-loading-state {
  align-items: center;
  justify-content: center;
  background: var(--clr-primary);
  min-height: 100dvh;
  padding-bottom: 0;
}

.loading-inner {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--sp-5);
}

.loading-logo {
  animation: spin-pulse 1.4s linear infinite;
}

@keyframes spin-pulse {
  0%   { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}

/* Stop the checkmark from spinning with the arc */
.loading-logo .spinner-check {
  animation: counter-spin 1.4s linear infinite;
}

@keyframes counter-spin {
  0%   { transform-origin: 28px 28px; transform: rotate(0deg); }
  100% { transform-origin: 28px 28px; transform: rotate(-360deg); }
}

.spinner-arc {
  stroke: #ffffff;
  opacity: 0.9;
}

.spinner-check {
  stroke: rgba(255,255,255,0.4);
}

.loading-label {
  font-size: 0.9375rem;
  font-weight: 500;
  color: rgba(255,255,255,0.75);
  letter-spacing: 0.04em;
}

/* ── Sign-In Screen ─────────────────────────────────────────── */
#screen-signin {
  align-items: center;
  justify-content: center;
  min-height: 100dvh;
  background: var(--clr-bg);
  padding-bottom: 0;
}

.signin-inner {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--sp-5);
  padding: var(--sp-8) var(--sp-6);
  max-width: 360px;
  width: 100%;
  text-align: center;
}

.signin-logo {
  opacity: 0.85;
}

.signin-title {
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--clr-primary);
  letter-spacing: -0.02em;
  margin: 0;
}

.signin-subtitle {
  font-size: 0.9375rem;
  color: var(--clr-text-body);
  line-height: 1.6;
  margin: 0;
}

.btn-google-signin {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--sp-3);
  width: 100%;
  min-height: 52px;
  background: #ffffff;
  color: #3c4043;
  font-size: 0.9375rem;
  font-weight: 600;
  border: 1.5px solid var(--clr-border);
  border-radius: var(--radius-md);
  box-shadow: 0 1px 3px rgba(0,0,0,0.08);
  transition: box-shadow var(--transition-fast), background var(--transition-fast);
  -webkit-tap-highlight-color: transparent;
  margin-top: var(--sp-2);
}

.btn-google-signin:hover:not(:disabled) {
  background: #f8f9fa;
  box-shadow: 0 2px 6px rgba(0,0,0,0.12);
}

.btn-google-signin:active:not(:disabled) {
  transform: scale(0.98);
}

.btn-google-signin:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}

/* ── Empty State ────────────────────────────────────────────── */
.empty-state {
  text-align: center;
  color: var(--clr-text-muted);
  font-size: 0.9375rem;
  padding: var(--sp-10) var(--sp-6);
}

/* ── Error Banner (fatal init error) ───────────────────────── */
.error-banner {
  background: var(--clr-error-light);
  border: 1px solid #f5c6c0;
  border-radius: var(--radius-md);
  padding: var(--sp-4);
  color: var(--clr-error);
  font-size: 0.9rem;
  font-weight: 500;
  margin: var(--sp-5);
  text-align: center;
}

/* ── Utility Classes ────────────────────────────────────────── */
.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip: rect(0,0,0,0);
  white-space: nowrap;
}

/* ── Responsive: Tablet / Desktop ──────────────────────────── */
@media (min-width: 600px) {
  .app-header {
    padding: var(--sp-5) var(--sp-8);
  }

  .screen-body {
    padding: var(--sp-6) var(--sp-8);
  }

  .app-title {
    font-size: 1.5rem;
  }

  .bottom-nav {
    max-width: 640px;
    left: 50%;
    transform: translateX(-50%);
    border-left: 1px solid var(--clr-border);
    border-right: 1px solid var(--clr-border);
    border-top-left-radius: var(--radius-lg);
    border-top-right-radius: var(--radius-lg);
  }
}

@media (min-width: 960px) {
  /* On wide screens give the content column some breathing room */
  .screen-body {
    padding: var(--sp-8) var(--sp-6);
  }

  .exercise-card:hover .card-header {
    background: var(--clr-primary-light);
  }
}

/* ── Focus Visible (keyboard nav) ──────────────────────────── */
:focus-visible {
  outline: 2px solid var(--clr-primary);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}

/* Suppress focus ring for mouse/touch */
:focus:not(:focus-visible) {
  outline: none;
}