/* ── APP SHARED ── */
.app-header {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  padding: 1rem 2rem;
  background: rgba(8, 28, 44, 0.9);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}
.app-header-inner {
  max-width: 1200px; margin: 0 auto;
  display: flex; align-items: center; justify-content: space-between;
}
.app-header .wordmark {
  font-family: var(--font-display); font-size: 1.25rem;
  font-weight: 700; color: var(--teal); text-decoration: none;
}
.app-header nav { display: flex; gap: 2rem; }
.app-header nav a {
  color: var(--text-muted); text-decoration: none;
  font-size: 0.85rem; letter-spacing: 0.04em; text-transform: uppercase;
  transition: color 0.2s;
}
.app-header nav a:hover { color: var(--teal); }

.app-container {
  max-width: 900px; margin: 0 auto;
  padding: 7rem 2rem 4rem;
  min-height: 100vh;
}

.app-footer {
  border-top: 1px solid var(--border);
  padding: 2rem;
  display: flex; align-items: center; gap: 1rem;
  justify-content: center;
}
.wordmark-sm {
  font-family: var(--font-display); font-size: 1rem;
  font-weight: 700; color: var(--teal);
}
.footer-tagline {
  font-size: 0.8rem; color: var(--text-dim); letter-spacing: 0.04em;
}

/* ── HUB ── */
.hub-grid {
  display: grid; grid-template-columns: 1fr 1fr; gap: 1.5rem;
  margin-bottom: 2.5rem;
}
.hub-card {
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: 16px; padding: 2rem; cursor: pointer;
  transition: border-color 0.3s, transform 0.2s;
}
.hub-card:hover { border-color: var(--teal); transform: translateY(-2px); }
.hub-card .card-icon {
  width: 48px; height: 48px; border-radius: 12px;
  display: flex; align-items: center; justify-content: center;
  font-size: 1.5rem; margin-bottom: 1.25rem;
}
.co2-card .card-icon { background: var(--amber-dim); }
.o2-card .card-icon { background: var(--teal-dim); }
.hub-card h2 {
  font-family: var(--font-display); font-size: 1.25rem;
  font-weight: 600; margin-bottom: 0.5rem; color: var(--text);
}
.hub-card p { font-size: 0.875rem; color: var(--text-muted); line-height: 1.6; }
.hub-card .card-tag {
  display: inline-block; font-size: 0.65rem; letter-spacing: 0.1em;
  text-transform: uppercase; padding: 0.2rem 0.6rem; border-radius: 4px;
  margin-bottom: 0.75rem; font-weight: 500;
}
.co2-card .card-tag { color: var(--amber); border: 1px solid var(--amber); }
.o2-card .card-tag { color: var(--teal); border: 1px solid var(--teal); }

.exercise-section { margin-top: 2rem; }
.exercise-section h2 {
  font-family: var(--font-display); font-size: 1.5rem;
  font-weight: 600; margin-bottom: 1.25rem; color: var(--text);
}
.exercise-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 1rem;
}
.exercise-card {
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: 12px; padding: 1.5rem; cursor: pointer;
  transition: border-color 0.3s;
}
.exercise-card:hover { border-color: var(--teal); }
.exercise-card .ex-tag {
  font-size: 0.65rem; letter-spacing: 0.1em; text-transform: uppercase;
  color: var(--teal); border: 1px solid var(--teal); border-radius: 4px;
  padding: 0.15rem 0.45rem; display: inline-block; margin-bottom: 0.75rem;
}
.exercise-card h3 {
  font-family: var(--font-display); font-size: 1rem; font-weight: 600;
  margin-bottom: 0.5rem; color: var(--text);
}
.exercise-card p { font-size: 0.8rem; color: var(--text-muted); line-height: 1.6; }
.exercise-card .ex-duration {
  font-size: 0.75rem; color: var(--text-dim); margin-top: 0.75rem;
}

/* ── ONBOARDING ── */
.onboard-wrap {
  display: flex; align-items: center; justify-content: center;
  min-height: calc(100vh - 8rem); padding: 2rem 0;
}
.onboard-card {
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: 20px; padding: 3rem; max-width: 560px; width: 100%;
}
.onboard-eyebrow {
  font-size: 0.7rem; letter-spacing: 0.18em; text-transform: uppercase;
  color: var(--teal); font-weight: 500; margin-bottom: 1rem;
}
.onboard-heading {
  font-family: var(--font-display); font-size: 2rem;
  font-weight: 600; color: var(--text); margin-bottom: 0.75rem;
  letter-spacing: -0.02em;
}
.onboard-sub {
  font-size: 0.95rem; color: var(--text-muted); line-height: 1.7;
  margin-bottom: 2.5rem;
}
.pb-fields { display: flex; flex-direction: column; gap: 2rem; margin-bottom: 2rem; }
.pb-field label {
  display: flex; align-items: center; gap: 0.75rem;
  font-size: 0.85rem; color: var(--text-muted); margin-bottom: 0.75rem;
}
.label-tag {
  font-size: 0.65rem; letter-spacing: 0.08em; text-transform: uppercase;
  font-weight: 500; padding: 0.2rem 0.5rem; border-radius: 4px;
}
.label-tag.co2 { color: var(--amber); border: 1px solid var(--amber); }
.label-tag.o2 { color: var(--teal); border: 1px solid var(--teal); }
.input-row { display: flex; align-items: center; gap: 0.75rem; }
.input-row input {
  background: var(--bg-alt); border: 1px solid var(--border);
  border-radius: 8px; color: var(--text); font-family: var(--font-body);
  font-size: 1.5rem; font-weight: 300; padding: 0.75rem 1rem;
  width: 120px; outline: none;
}
.input-row input:focus { border-color: var(--teal); }
.input-unit { font-size: 0.875rem; color: var(--text-muted); }
.pb-hint { font-size: 0.78rem; color: var(--text-dim); margin-top: 0.5rem; }

.btn-primary {
  background: var(--teal); color: var(--bg); border: none;
  border-radius: 10px; font-family: var(--font-body); font-size: 1rem;
  font-weight: 500; padding: 0.875rem 1.75rem; cursor: pointer;
  display: inline-flex; align-items: center; gap: 0.5rem;
  transition: background 0.2s, transform 0.1s;
}
.btn-primary:hover { background: #00d9bf; transform: translateY(-1px); }
.btn-primary:active { transform: translateY(0); }

.onboard-note {
  display: flex; align-items: flex-start; gap: 0.5rem;
  font-size: 0.78rem; color: var(--text-dim); margin-top: 1.5rem;
  line-height: 1.5;
}
.onboard-note svg { flex-shrink: 0; margin-top: 1px; }

/* ── TIMER ── */
.timer-wrap { display: flex; flex-direction: column; align-items: center; text-align: center; }

.timer-nav {
  display: flex; align-items: center; gap: 1rem; margin-bottom: 3rem;
}
.timer-nav a {
  color: var(--text-muted); text-decoration: none;
  font-size: 0.85rem; transition: color 0.2s;
}
.timer-nav a:hover { color: var(--teal); }
.timer-nav .sep { color: var(--text-dim); }

.timer-type-label {
  font-size: 0.7rem; letter-spacing: 0.18em; text-transform: uppercase;
  font-weight: 500; padding: 0.3rem 0.75rem; border-radius: 4px;
  display: inline-block; margin-bottom: 1rem;
}
.timer-type-label.co2 { color: var(--amber); border: 1px solid var(--amber); }
.timer-type-label.o2 { color: var(--teal); border: 1px solid var(--teal); }

.timer-phase {
  font-size: 0.85rem; letter-spacing: 0.1em; text-transform: uppercase;
  color: var(--text-muted); margin-bottom: 1.5rem;
}

.timer-circle-wrap { position: relative; display: inline-block; margin-bottom: 1.5rem; }
.timer-circle {
  width: 280px; height: 280px; border-radius: 50%;
  border: 2px solid var(--border); position: relative;
  display: flex; align-items: center; justify-content: center;
  background: var(--bg-card);
}
.timer-circle.active {
  border-color: var(--teal);
  box-shadow: 0 0 40px rgba(0, 196, 167, 0.15);
}
.timer-circle.rest {
  border-color: var(--amber);
  box-shadow: 0 0 40px rgba(245, 166, 35, 0.1);
}
.progress-ring {
  position: absolute; inset: -2px; border-radius: 50%;
  background: conic-gradient(var(--teal) 0deg, transparent 0deg);
  transition: background 0.1s;
}
.progress-ring.rest {
  background: conic-gradient(var(--amber) 0deg, transparent 0deg);
}
.timer-inner {
  position: relative; z-index: 1; display: flex; flex-direction: column;
  align-items: center; gap: 0.5rem;
}
.timer-time {
  font-family: var(--font-display); font-size: 3.5rem;
  font-weight: 700; color: var(--text); letter-spacing: -0.03em;
  line-height: 1;
}
.timer-time.co2 { color: var(--amber); }
.timer-time.o2 { color: var(--teal); }
.timer-sublabel { font-size: 0.75rem; color: var(--text-dim); letter-spacing: 0.08em; }

.timer-controls { display: flex; gap: 1rem; margin-bottom: 2rem; }
.btn-timer {
  border-radius: 10px; font-family: var(--font-body); font-size: 0.95rem;
  font-weight: 500; padding: 0.75rem 1.75rem; cursor: pointer;
  border: none; transition: all 0.2s;
}
.btn-start { background: var(--teal); color: var(--bg); }
.btn-start:hover { background: #00d9bf; }
.btn-pause { background: var(--bg-alt); color: var(--text); border: 1px solid var(--border); }
.btn-pause:hover { border-color: var(--teal); }
.btn-reset { background: transparent; color: var(--text-muted); border: 1px solid var(--border); }
.btn-reset:hover { color: var(--text); border-color: var(--text-muted); }

.timer-table { width: 100%; margin-top: 2rem; }
.timer-table table { width: 100%; border-collapse: collapse; }
.timer-table th {
  font-size: 0.65rem; letter-spacing: 0.12em; text-transform: uppercase;
  color: var(--text-dim); text-align: left; padding: 0.75rem 1rem;
  border-bottom: 1px solid var(--border);
}
.timer-table td {
  font-size: 0.9rem; color: var(--text-muted); padding: 0.6rem 1rem;
  border-bottom: 1px solid rgba(0,196,167,0.07);
}
.timer-table td:first-child { color: var(--text-dim); }
.timer-table td.hold { color: var(--amber); font-weight: 500; }
.timer-table td.rest { color: var(--teal); font-weight: 500; }
.timer-table tr.current td { color: var(--text); background: var(--teal-dim); }
.timer-table tr.current td.hold { color: var(--amber); }

/* ── EXERCISE ── */
.exercise-view { max-width: 600px; margin: 0 auto; }
.back-btn {
  display: inline-flex; align-items: center; gap: 0.4rem;
  color: var(--text-muted); text-decoration: none; font-size: 0.85rem;
  margin-bottom: 2rem; transition: color 0.2s;
}
.back-btn:hover { color: var(--teal); }
.exercise-header {
  display: flex; align-items: flex-start; justify-content: space-between;
  margin-bottom: 1.5rem;
}
.exercise-title {
  font-family: var(--font-display); font-size: 2rem; font-weight: 600;
  color: var(--text); letter-spacing: -0.02em;
}
.exercise-meta {
  font-size: 0.8rem; color: var(--text-dim); margin-top: 0.5rem;
}
.ex-steps {
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: 14px; padding: 2rem; margin-bottom: 1.5rem;
}
.ex-steps h3 {
  font-family: var(--font-display); font-size: 1.1rem; font-weight: 600;
  color: var(--text); margin-bottom: 1.25rem;
}
.ex-steps ol { padding-left: 1.5rem; }
.ex-steps li {
  font-size: 0.95rem; color: var(--text-muted); line-height: 1.7;
  margin-bottom: 0.75rem;
}
.ex-steps li::marker { color: var(--teal); }

.ex-timer {
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: 14px; padding: 2rem; text-align: center; margin-bottom: 1.5rem;
}
.ex-timer-display {
  font-family: var(--font-display); font-size: 3rem; font-weight: 700;
  color: var(--teal); margin-bottom: 0.5rem; letter-spacing: -0.03em;
}
.ex-timer-label { font-size: 0.8rem; color: var(--text-dim); letter-spacing: 0.08em; text-transform: uppercase; }

.btn-ex-start {
  width: 100%; background: var(--teal); color: var(--bg);
  border: none; border-radius: 10px; font-family: var(--font-body);
  font-size: 1rem; font-weight: 500; padding: 1rem; cursor: pointer;
  transition: background 0.2s;
}
.btn-ex-start:hover { background: #00d9bf; }

/* ── LOADING ── */
.loading { text-align: center; padding: 4rem; color: var(--text-muted); font-size: 1rem; }

/* ── RESPONSIVE ── */
@media (max-width: 700px) {
  .hub-grid { grid-template-columns: 1fr; }
  .timer-circle { width: 220px; height: 220px; }
  .timer-time { font-size: 2.5rem; }
  .onboard-card { padding: 2rem 1.5rem; }
}