:root {
    color-scheme: light;
    --ink: #1d1d1f;
    --secondary: #6e6e73;
    --line: #e8e8ed;
    --surface: #f5f5f7;
    --blue: #0071e3;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI Variable", "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei UI", sans-serif;
    color: var(--ink);
    background: #fff;
    font-synthesis: none;
    -webkit-font-smoothing: antialiased;
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }
body { margin: 0; min-width: 320px; }
h1, h2, h3, p { margin: 0; }
button, input, select { font: inherit; }
button { cursor: pointer; border: 0; font-weight: 500; transition: background 160ms, opacity 160ms; }
button:disabled { opacity: .35; cursor: default; }
button:focus-visible, a:focus-visible { outline: 2px solid var(--blue); outline-offset: 4px; }
button:active:not(:disabled) { opacity: .7; }
input, select { min-width: 0; width: 100%; color: var(--ink); }
input:focus, select:focus { outline: 2px solid var(--blue); outline-offset: 2px; }
.page { width: min(1120px, 100%); margin: 0 auto; padding: 40px 48px; }
.topbar, .section-heading { display: flex; align-items: center; justify-content: space-between; gap: 16px; }
.topbar { margin-bottom: 40px; }
h1 { font-size: 26px; font-weight: 600; letter-spacing: -.04em; }
h2 { font-size: 20px; font-weight: 600; letter-spacing: -.02em; }
h3 { font-size: 15px; font-weight: 500; }
.back-link { color: var(--secondary); text-decoration: none; font-size: 14px; }
.back-link:hover { color: var(--blue); }
.primary, .secondary { min-height: 44px; border-radius: 24px; padding: 0 24px; }
.primary { background: var(--ink); color: #fff; }
.primary:hover:not(:disabled) { background: #363638; }
.secondary { background: #f0f0f2; color: var(--ink); }
.secondary:hover:not(:disabled) { background: #e8e8ed; }
.meta, .section-note, .config-summary { color: var(--secondary); font-size: 13px; font-weight: 400; line-height: 1.6; }
.section-note { margin-top: 12px; }
.layout { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); gap: 64px; align-items: start; }
.panel { min-width: 0; }
.config-panel { margin-top: 28px; }
.config-heading { display: flex; align-items: baseline; gap: 10px; }
.config-list { display: grid; gap: 20px; margin-top: 20px; }
.exercise-config { padding: 20px; border: 1px solid var(--line); border-radius: 18px; background: var(--surface); }
.exercise-config .config-top { padding-bottom: 18px; border-bottom: 1px solid #dedee3; }
.exercise-config [data-field="name"] { font-weight: 500; }
.exercise-config input, .exercise-config select { border-color: #dedee3; }
.config-top { display: grid; grid-template-columns: minmax(0, 1fr) 90px 32px; gap: 12px; align-items: end; }
.config-label { display: grid; gap: 8px; font-size: 12px; font-weight: 400; color: var(--secondary); }
input, select { border: 1px solid #d2d2d7; border-radius: 9px; background: #fff; min-height: 40px; padding: 8px 10px; font-size: 14px; }
input:disabled { color: var(--secondary); background: var(--surface); border-color: transparent; }
.config-fields { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; margin-top: 18px; }
.exercise-config .config-fields { grid-template-columns: 1fr; }
.options-heading { display: flex; justify-content: space-between; align-items: center; gap: 12px; margin: 20px 0 10px; font-size: 12px; color: var(--secondary); }
.text-btn, .add-exercise { color: var(--blue); background: transparent; font-size: 13px; padding: 8px 0; }
.add-exercise { white-space: nowrap; min-height: 36px; }
.option-list { display: grid; gap: 10px; }
.option-row { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1fr) 60px 28px; gap: 10px; align-items: end; }
.exercise-config[data-mode="time"] .option-row { grid-template-columns: minmax(0, 1fr) 60px 28px; }
.exercise-config[data-mode="time"] .option-row > div:first-child { display: none; }
.icon-btn, .remove-option { width: 32px; height: 40px; background: transparent; color: var(--secondary); font-size: 20px; }
.icon-btn:hover, .remove-option:hover { color: #b42318; }
.form-row { display: grid; gap: 10px; margin-top: 28px; font-size: 14px; }
.button-row { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; margin-top: 24px; }
.wide-btn { width: 100%; margin-top: 24px; }
.stats { display: grid; grid-template-columns: 1fr 1fr; gap: 24px 16px; margin-top: 32px; }
.stat-label { font-size: 12px; color: var(--secondary); margin-bottom: 6px; }
.stat-value { font-size: 14px; }
.plan-preview { position: sticky; top: 40px; }
.plan-list { margin-top: 24px; max-height: 65vh; overflow-y: auto; }
.plan-item { display: grid; grid-template-columns: 28px minmax(0, 1fr) auto; gap: 14px; align-items: center; padding: 18px 0; border-bottom: 1px solid var(--line); }
.badge { font-size: 12px; color: var(--secondary); }
.item-title { font-size: 15px; font-weight: 500; overflow-wrap: anywhere; }
.item-subtitle { font-size: 12px; color: var(--secondary); margin-top: 5px; }
.item-time { font-size: 14px; font-variant-numeric: tabular-nums; }
.empty { padding: 32px 0; color: var(--secondary); font-size: 14px; }

/* One shared baseline for navigation; one shared centerline for the timer. */
.session-header { display: flex; align-items: center; justify-content: space-between; gap: 24px; padding-bottom: 28px; border-bottom: 1px solid var(--line); }
.session-heading, .session-actions { display: flex; align-items: center; gap: 24px; }
.session-header h1 { font-size: 20px; }
#session-progress-label, #session-remaining { color: var(--secondary); font-size: 13px; white-space: nowrap; font-variant-numeric: tabular-nums; }
.session-actions button { min-height: 36px; padding: 0 18px; font-size: 13px; }
.session-layout { display: grid; grid-template-columns: minmax(0, 1fr) 280px; gap: 56px; padding-top: 40px; }
.current-card { min-width: 0; display: flex; flex-direction: column; }
.current-type { color: var(--secondary); font-size: 13px; line-height: 24px; min-height: 24px; }
.timer-face { text-align: center; padding: 36px 0 32px; }
.current-name { font-size: 32px; line-height: 1.4; font-weight: 500; letter-spacing: -.035em; overflow-wrap: anywhere; }
.time-display { margin-top: 12px; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI Variable Display", "Segoe UI", sans-serif; font-size: clamp(80px, 10vw, 128px); font-weight: 300; letter-spacing: -.065em; line-height: 1.08; font-variant-numeric: tabular-nums; }
.rep-status { min-height: 28px; margin-top: 18px; display: flex; align-items: center; justify-content: center; gap: 16px; }
.rep-count { font-size: 16px; color: var(--secondary); font-variant-numeric: tabular-nums; }
.beat-display { display: flex; align-items: center; gap: 5px; height: 18px; }
.beat-display span { display: block; width: 4px; height: 8px; border-radius: 4px; background: #d2d2d7; transition: background 100ms; }
.beat-display #heavy-beat { height: 14px; }
.beat-display span.active { background: var(--blue); }
.timer-footer { width: min(100%, 360px); margin: auto auto 0; }
.progress-track { height: 3px; border-radius: 3px; overflow: hidden; background: var(--line); }
.progress-bar { width: 0%; height: 100%; background: var(--blue); transition: width 100ms linear; }
.rep-progress { display: grid; grid-template-columns: repeat(8, minmax(0, 1fr)); gap: 5px; max-height: 99px; overflow-y: auto; scrollbar-width: thin; }
.rep-block { height: 8px; border-radius: 3px; background: var(--line); }
.rep-block.done { background: var(--blue); }
.session-controls { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; margin-top: 28px; }
.session-controls button { height: 48px; font-size: 15px; font-weight: 500; }
#sound-status:empty { display: none; }
.upcoming-card { min-width: 0; border-left: 1px solid var(--line); padding-left: 32px; }
.upcoming-card h2 { font-size: 13px; line-height: 24px; font-weight: 500; color: var(--secondary); }
.upcoming-card .meta { font-size: 12px; }
.upcoming-list { margin-top: 20px; }
.upcoming-item { display: grid; grid-template-columns: 24px minmax(0, 1fr) auto; align-items: baseline; gap: 12px; padding: 24px 0; border-bottom: 1px solid var(--line); }
.upcoming-item:last-of-type { border-bottom: 0; }
.upcoming-number { font-size: 12px; color: var(--secondary); font-variant-numeric: tabular-nums; }
.upcoming-item .item-title { font-size: 16px; line-height: 1.5; font-weight: 400; }
.upcoming-value { font-size: 14px; color: var(--secondary); white-space: nowrap; font-variant-numeric: tabular-nums; }
.upcoming-list > .section-note { font-size: 12px; margin-top: 16px; }

@media (max-width: 820px) {
    .page { padding: 28px; }
    .layout { gap: 32px; }
    .session-layout { grid-template-columns: minmax(0, 1fr) 230px; gap: 32px; }
    .upcoming-card { padding-left: 24px; }
}

@media (orientation: portrait), (max-width: 600px) {
    .session-layout { grid-template-columns: 1fr; gap: 40px; padding-top: 24px; }
    .timer-face { padding: 24px 0; }
    .time-display { font-size: clamp(88px, 21vw, 128px); }
    .current-name { font-size: 28px; }
    .timer-footer { width: 100%; }
    .upcoming-card { padding: 24px 0 0; border-left: 0; border-top: 1px solid var(--line); }
    .upcoming-list { margin-top: 8px; }
    .upcoming-item { padding: 20px 0; grid-template-columns: 28px minmax(0, 1fr) auto; }
}

@media (max-width: 600px) {
    .page { padding: 24px; }
    .topbar { margin-bottom: 32px; }
    .layout { grid-template-columns: 1fr; gap: 40px; }
    .plan-preview { position: static; }
    .session-header { gap: 12px; padding-bottom: 20px; }
    .session-heading { gap: 12px; }
    .session-actions { gap: 12px; }
    #session-remaining { display: none; }
    .session-header h1 { font-size: 18px; }
    .session-layout { gap: 32px; }
    .session-controls { margin-top: 24px; }
    .exercise-config { padding: 16px; }
    .config-top { grid-template-columns: minmax(0, 1fr) 66px 24px; gap: 8px; }
    .option-row { gap: 6px; grid-template-columns: minmax(0, 1fr) minmax(0, 1fr) 44px 24px; }
    .exercise-config input, .exercise-config select { padding-inline: 8px; }
}

@media (orientation: landscape) and (max-height: 600px) {
    .page { padding: 20px 36px; }
    .session-header { padding-bottom: 16px; }
    .session-layout { padding-top: 20px; grid-template-columns: minmax(0, 1fr) minmax(210px, .65fr); gap: 40px; }
    .timer-face { padding: 8px 0 8px; }
    .rep-progress { max-height: 61px; gap: 3px; }
    .rep-block { height: 5px; }
    .reps-mode .time-display { font-size: clamp(60px, 8vw, 72px); }
    .reps-mode .session-controls { margin-top: 10px; }
    .reps-mode .session-layout { padding-top: 12px; }
    .reps-mode .timer-face { padding: 4px 0; }
    .current-name { font-size: 24px; line-height: 1.3; }
    .time-display { font-size: clamp(64px, 9vw, 88px); margin-top: 2px; }
    .rep-status { margin-top: 6px; min-height: 20px; }
    .rep-count { font-size: 14px; }
    .session-controls { margin-top: 18px; }
    .session-controls button { height: 42px; min-height: 42px; }
    .upcoming-list { margin-top: 8px; }
    .upcoming-item { padding: 20px 0; }
}

@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after { transition: none !important; animation: none !important; }
}