/* === Variables === */
:root {
  --bg: #fff;
  --text: #0a0a0a;
  --muted: #777;
  --accent: #0a0a0a;
  --border: #e8e8e8;
  --font: 'Inter', system-ui, sans-serif;
  --max-w: 640px;
  --radius: 8px;
  --transition: .2s ease;
}

[data-theme="dark"] {
  --bg: #0a0a0a;
  --text: #f0f0f0;
  --muted: #666;
  --accent: #f0f0f0;
  --border: #222;
}

/* === Reset === */
* { margin: 0; padding: 0; box-sizing: border-box; }

/* === Base === */
body {
  font: 400 1rem/1.6 var(--font);
  color: var(--text);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
}

html { -webkit-text-size-adjust: 100%; overflow-x: clip; }

a { color: inherit; text-decoration: none; }
@media (hover: hover) { a:hover { opacity: .6; } }
ul { list-style: none; }

.skip-link {
  position: absolute; left: -9999px; top: auto;
  width: 1px; height: 1px; overflow: hidden;
  z-index: 100; padding: 12px 16px;
  background: var(--text); color: var(--bg); font-size: .875rem;
}
.skip-link:focus { left: 24px; top: 24px; width: auto; height: auto; overflow: visible; }

a:focus { outline: 1px solid var(--text); outline-offset: 2px; }

/* === Layout === */
.container {
  max-width: var(--max-w);
  margin: 0 auto;
  padding-left: max(28px, env(safe-area-inset-left));
  padding-right: max(28px, env(safe-area-inset-right));
}

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

/* === Header & Nav === */
.hamburger {
  position: fixed; top: 20px; right: 20px; z-index: 250;
  width: 44px; height: 44px;
  display: flex; align-items: center; justify-content: center;
  background: none; border: 1px solid var(--border); border-radius: 8px;
  cursor: pointer; color: var(--text);
  transition: border-color var(--transition);
}
.hamburger:hover { border-color: var(--text); }
.hamburger svg { display: block; }

/* === Sidebar === */
.sidebar-overlay {
  position: fixed; inset: 0; background: rgba(0,0,0,.4);
  z-index: 400; opacity: 0; pointer-events: none; transition: opacity var(--transition);
}
.sidebar-overlay.open { opacity: 1; pointer-events: auto; }

.sidebar {
  position: fixed; top: 0; right: 0; bottom: 0; z-index: 450;
  width: 280px; max-width: 80vw;
  background: var(--bg); border-left: 1px solid var(--border);
  display: flex; flex-direction: column;
  padding: max(24px, env(safe-area-inset-top)) 24px 24px;
  transform: translateX(100%); transition: transform .25s ease;
}
.sidebar-overlay.open .sidebar { transform: translateX(0); }

.sidebar-close {
  align-self: flex-end; width: 44px; height: 44px;
  display: flex; align-items: center; justify-content: center;
  background: none; border: 1px solid var(--border); border-radius: 8px;
  cursor: pointer; color: var(--text); margin-bottom: 24px;
  transition: border-color var(--transition);
}
.sidebar-close:hover { border-color: var(--text); }

.sidebar-nav { display: flex; flex-direction: column; gap: 4px; }
.sidebar-nav a {
  padding: 12px 16px; border-radius: 8px;
  font-size: .875rem; text-transform: uppercase; letter-spacing: .05em;
  transition: background var(--transition); cursor: pointer;
}
.sidebar-nav a:hover { background: var(--border); opacity: 1; }
.sidebar-nav a.active { background: var(--text); color: var(--bg); }

.sidebar-section-label { font-size: .6875rem; color: var(--muted); text-transform: uppercase; letter-spacing: .1em; margin: 20px 0 8px; padding: 0 16px; }

.sidebar-controls { display: flex; flex-direction: column; gap: 8px; padding: 0 16px; }
.sidebar-row { display: flex; align-items: center; justify-content: space-between; padding: 8px 0; }
.sidebar-row span { font-size: .8125rem; color: var(--muted); }

.theme-btn, .lang-btn {
  background: none; border: 1px solid var(--border); border-radius: 4px;
  padding: 6px 12px; cursor: pointer; color: var(--text);
  font: inherit; font-size: .75rem; text-transform: uppercase; letter-spacing: .05em;
  transition: border-color var(--transition);
}
.theme-btn:hover, .lang-btn:hover { border-color: var(--text); }

.sidebar-footer { margin-top: auto; padding-top: 16px; }

/* === Timer === */
.view-timer {
  padding-top: 20px; min-height: 100vh;
  display: none; flex-direction: column; align-items: center; justify-content: center;
}
.view-timer.active { display: flex; }
.view-timer .container { text-align: center; }
.view-timer .label { display: block; margin-bottom: 24px; }

.mode-tabs { display: flex; justify-content: center; gap: 4px; margin-bottom: 32px; }
.mode-tab {
  padding: 8px 20px; border: 1px solid var(--border); border-radius: 100px;
  background: none; color: var(--muted); font: inherit; font-size: .8125rem;
  cursor: pointer; transition: all var(--transition);
}
.mode-tab:hover { border-color: var(--text); color: var(--text); }
.mode-tab.active { background: var(--text); color: var(--bg); border-color: var(--text); }

.timer-display {
  font-size: clamp(4rem, 20vw, 8rem); font-weight: 700;
  letter-spacing: -.04em; font-variant-numeric: tabular-nums;
  line-height: 1; margin-bottom: 8px;
}
.timer-round { font-size: .875rem; color: var(--muted); margin-bottom: 24px; }

.timer-controls { display: flex; justify-content: center; gap: 12px; margin-bottom: 20px; flex-wrap: wrap; }
.timer-btn {
  padding: 12px 32px; border: 1px solid var(--text); border-radius: 100px;
  background: none; color: var(--text); font: inherit; font-size: .875rem;
  cursor: pointer; transition: all var(--transition); min-height: 48px;
}
.timer-btn:hover { background: var(--text); color: var(--bg); }
.timer-btn.primary { background: var(--text); color: var(--bg); }
.timer-btn.primary:hover { opacity: .8; }

.timer-tip {
  margin: 0 auto 16px; max-width: 440px;
  opacity: 0; transform: translateY(-8px); transition: all .3s ease;
  pointer-events: none;
}
.timer-tip.visible { opacity: 1; transform: translateY(0); pointer-events: auto; }

.timer-tip-inner {
  display: flex; align-items: flex-start; gap: 12px;
  padding: 14px 18px; border: 1px solid var(--border);
  border-radius: var(--radius); background: var(--bg);
  text-align: left;
}
.timer-tip-icon { font-size: 1.25rem; flex-shrink: 0; margin-top: 1px; }
.timer-tip-text { font-size: .875rem; font-weight: 500; }
.timer-tip-source { font-size: .6875rem; color: var(--muted); margin-top: 2px; }

/* === Focus Mode === */
.focus-btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 10px 24px; border: 1px solid var(--border); border-radius: 100px;
  background: none; color: var(--muted); font: inherit; font-size: .8125rem;
  cursor: pointer; transition: all var(--transition);
}
.focus-btn:hover { border-color: var(--text); color: var(--text); }

.focus-overlay {
  position: fixed; inset: 0; background: var(--bg); z-index: 600;
  display: flex; flex-direction: column; align-items: center; justify-content: center;
  opacity: 0; pointer-events: none; transition: opacity var(--transition);
}
.focus-overlay.open { opacity: 1; pointer-events: auto; }
.focus-overlay .timer-display { font-size: clamp(6rem, 25vw, 12rem); }
.focus-overlay .timer-round { font-size: 1rem; }
.focus-overlay .timer-btn { font-size: 1rem; padding: 16px 48px; }
.focus-overlay .timer-tip { max-width: 500px; }
.focus-exit {
  position: absolute; top: 24px; right: 24px;
  background: none; border: 1px solid var(--border); border-radius: 100px;
  color: var(--muted); font: inherit; font-size: .75rem; padding: 8px 16px;
  cursor: pointer; text-transform: uppercase; letter-spacing: .05em;
}
.focus-exit:hover { border-color: var(--text); color: var(--text); }

/* === Stats === */
.stats-bar {
  display: flex; justify-content: center; gap: 32px; flex-wrap: wrap;
  margin-top: 28px; padding: 20px 0 16px; border-top: 1px solid var(--border);
}
.stat-item { text-align: center; }
.stat-value { font-size: 1.25rem; font-weight: 700; }
.stat-label { font-size: .6875rem; color: var(--muted); text-transform: uppercase; letter-spacing: .05em; }

.chart-wrap { padding: 16px 0 20px; border-top: 1px solid var(--border); }
.chart-wrap .stat-label { display: block; margin-bottom: 12px; }
.chart { display: flex; align-items: flex-end; gap: 4px; height: 60px; }
.chart-bar {
  flex: 1; border-radius: 3px 3px 0 0; min-height: 2px;
  background: var(--border); transition: height .3s ease;
}
.chart-bar.fill { background: var(--text); }
.chart-labels { display: flex; gap: 4px; margin-top: 4px; }
.chart-labels span {
  flex: 1; font-size: .625rem; color: var(--muted);
  text-transform: uppercase; text-align: center; letter-spacing: .02em;
}

/* === Tips === */
.view-tips { padding: 48px 0 80px; display: none; min-height: 100vh; }
.view-tips.active { display: block; }
.view-tips > .container > .label { display: block; margin-bottom: 8px; }
.tips-desc { font-size: .9rem; color: var(--muted); margin-bottom: 32px; }

.tips-category { margin-bottom: 12px; border: 1px solid var(--border); border-radius: var(--radius); overflow: hidden; }
.tips-category:last-child { margin-bottom: 0; }

.tips-category-header {
  display: flex; align-items: center; justify-content: space-between;
  width: 100%; padding: 18px 24px;
  background: none; border: none; cursor: pointer;
  color: var(--text); font: inherit; font-size: 1rem;
  text-align: left; transition: background var(--transition);
}
.tips-category-header:hover { background: var(--border); }
.tips-category-header h2 { font-weight: 500; font-size: 1rem; }
.toggle-icon {
  font-size: 1.25rem; color: var(--muted); flex-shrink: 0;
  transition: transform var(--transition); line-height: 1;
}

.tips-category-body { padding: 8px 28px 24px; }
.tips-category-body .tip-item:first-child { padding-top: 12px; }

.tip-item {
  padding: 14px 0 14px 4px; border-bottom: 1px solid var(--border);
}
.tip-item:last-child { border-bottom: none; }

.tip-item-body strong {
  display: block; font-weight: 500; font-size: 1rem; margin-bottom: 4px;
}
.tip-item-body span {
  display: block; font-size: .875rem; color: var(--muted); line-height: 1.6;
}

/* === Sound Controls === */
.sound-controls { display: flex; justify-content: center; gap: 6px; margin-bottom: 16px; }
.sound-btn {
  padding: 6px 14px; border: 1px solid var(--border); border-radius: 100px;
  background: none; color: var(--muted); font: inherit; font-size: .75rem;
  cursor: pointer; transition: all var(--transition);
}
.sound-btn:hover { border-color: var(--text); color: var(--text); }
.sound-btn.active { background: var(--text); color: var(--bg); border-color: var(--text); }

/* === Task Input === */
.task-input-wrap { margin-bottom: 24px; }
.task-input {
  width: 100%; max-width: 360px; padding: 10px 14px;
  border: 1px solid var(--border); border-radius: var(--radius);
  background: var(--bg); color: var(--text);
  font: inherit; font-size: .875rem; text-align: center;
  transition: border-color var(--transition);
}
.task-input:focus { outline: 1px solid var(--text); }
.task-input::placeholder { color: var(--muted); }
.task-done { font-size: .875rem; color: var(--muted); margin-bottom: 24px; display: flex; align-items: center; justify-content: center; gap: 8px; }
.task-done .check { color: #2ecc71; font-weight: 700; }

/* === Settings Modal === */
.modal-overlay {
  position: fixed; inset: 0; background: rgba(0,0,0,.5);
  display: flex; align-items: center; justify-content: center;
  z-index: 500; padding: 24px;
  opacity: 0; pointer-events: none; transition: opacity var(--transition);
}
.modal-overlay.open { opacity: 1; pointer-events: auto; }
.modal {
  background: var(--bg); border-radius: var(--radius);
  padding: 32px; max-width: 400px; width: 100%; position: relative;
}
.modal h2 { font-size: 1rem; font-weight: 500; margin-bottom: 20px; }
.modal-close {
  position: absolute; top: 16px; right: 16px;
  background: none; border: none; color: var(--muted);
  font-size: 1.25rem; cursor: pointer; padding: 4px; line-height: 1;
}
.modal-field { margin-bottom: 16px; }
.modal-field label {
  display: block; font-size: .75rem; color: var(--muted);
  margin-bottom: 4px; text-transform: uppercase; letter-spacing: .05em;
}
.modal-field input[type="number"] {
  width: 100%; padding: 10px 12px; border: 1px solid var(--border); border-radius: 4px;
  background: var(--bg); color: var(--text); font: inherit; font-size: .875rem;
}
.modal-field input[type="number"]:focus { outline: 1px solid var(--text); }
.modal-field input[type="checkbox"] { margin-right: 8px; }
.modal-field .checkbox-label { font-size: .875rem; color: var(--text); text-transform: none; letter-spacing: 0; display: inline; cursor: pointer; }
.modal-save {
  width: 100%; padding: 12px; border: 1px solid var(--text); border-radius: 4px;
  background: var(--text); color: var(--bg); font: inherit; font-size: .875rem;
  cursor: pointer; margin-top: 8px;
}
.modal-save:hover { opacity: .8; }

/* === Footer === */
.site-footer { padding: 40px 0 max(40px, env(safe-area-inset-bottom)); text-align: center; }

/* === Responsive === */
@media (max-width: 640px) {
  .view-timer { padding-top: 0; }
  .mode-tabs { gap: 2px; }
  .mode-tab { padding: 6px 14px; font-size: .75rem; }
  .timer-controls { gap: 8px; }
  .timer-btn { padding: 10px 24px; }
  .stats-bar { gap: 20px; }
  .focus-overlay .timer-display { font-size: clamp(4rem, 20vw, 8rem); }
  .focus-overlay .timer-btn { padding: 12px 32px; font-size: .875rem; }
  .tips-category-header { padding: 14px 18px; }
  .tips-category-body { padding: 6px 22px 18px; }
  .tip-item { padding: 12px 0 12px 2px; }
}

@media (max-width: 380px) {
  .sidebar { width: 100vw; max-width: 100vw; }
}

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