/* ==========================================================================
   Design System & Theme Tokens
   ========================================================================== */

:root {
  /* Common metrics */
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --radius-full: 9999px;
  --transition-speed: 0.25s;
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-mono: 'JetBrains Mono', 'SF Mono', Consolas, Monaco, monospace;
}

/* Dark Theme (Default) */
html[data-theme="dark"],
body.theme-dark {
  --bg-primary: #090a0f;
  --bg-secondary: #141720;
  --bg-tertiary: #1f2330;
  --bg-translucent: rgba(20, 23, 32, 0.75);
  
  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  
  --accent-color: #3b82f6;
  --accent-hover: #2563eb;
  --accent-glow: rgba(59, 130, 246, 0.35);
  
  --border-color: rgba(255, 255, 255, 0.08);
  --border-focus: rgba(255, 255, 255, 0.25);
  
  --control-btn-bg: #181b24;
  --control-btn-border: rgba(255, 255, 255, 0.12);
  --control-btn-hover: #232734;
  
  --primary-btn-bg: #ffffff;
  --primary-btn-text: #090a0f;
  --primary-btn-hover: #e2e8f0;
  
  --shadow-sm: 0 4px 12px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 16px 40px rgba(0, 0, 0, 0.6);
  --progress-glow: rgba(59, 130, 246, 0.5);
  --digit-glow: rgba(248, 250, 252, 0.04);
}

/* Light Theme */
html[data-theme="light"],
body.theme-light {
  --bg-primary: #f8f9fa;
  --bg-secondary: #ffffff;
  --bg-tertiary: #edf0f5;
  --bg-translucent: rgba(255, 255, 255, 0.85);
  
  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-muted: #94a3b8;
  
  --accent-color: #2563eb;
  --accent-hover: #1d4ed8;
  --accent-glow: rgba(37, 99, 235, 0.2);
  
  --border-color: rgba(0, 0, 0, 0.08);
  --border-focus: rgba(0, 0, 0, 0.2);
  
  --control-btn-bg: #ffffff;
  --control-btn-border: rgba(0, 0, 0, 0.1);
  --control-btn-hover: #f1f5f9;
  
  --primary-btn-bg: #0f172a;
  --primary-btn-text: #ffffff;
  --primary-btn-hover: #1e293b;
  
  --shadow-sm: 0 4px 12px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 16px 40px rgba(0, 0, 0, 0.12);
  --progress-glow: rgba(37, 99, 235, 0.3);
  --digit-glow: rgba(15, 23, 42, 0.03);
}

/* ==========================================================================
   Base & Reset
   ========================================================================== */

*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

html, body {
  width: 100%;
  height: 100%;
  overflow: hidden;
  font-family: var(--font-sans);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  transition: background-color var(--transition-speed) ease, color var(--transition-speed) ease;
  user-select: none;
}

body {
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  min-height: 100vh;
  position: relative;
}

/* Utility hide */
.hide {
  display: none !important;
}

/* Accessible Off-Screen Content for SEO & Screen Readers */
.visually-hidden {
  position: absolute !important;
  width: 1px !important;
  height: 1px !important;
  padding: 0 !important;
  margin: -1px !important;
  overflow: hidden !important;
  clip: rect(0, 0, 0, 0) !important;
  white-space: nowrap !important;
  border: 0 !important;
}

/* ==========================================================================
   Header / Top Navigation Bar
   ========================================================================== */

.top-bar {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  padding: 1.25rem 2rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  z-index: 50;
  transition: opacity 0.4s ease, transform 0.4s ease;
}

.brand-badge {
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--text-muted);
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  padding: 0.35rem 0.75rem;
  border-radius: var(--radius-full);
}

.top-actions {
  display: flex;
  align-items: center;
  gap: 1rem;
}

/* Icon Action Buttons */
.icon-btn {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  width: 40px;
  height: 40px;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all 0.2s ease;
  outline: none;
}

.icon-btn:hover {
  color: var(--text-primary);
  background: var(--bg-tertiary);
  border-color: var(--border-focus);
  transform: translateY(-1px);
}

.icon-btn:active {
  transform: translateY(0);
}

/* ==========================================================================
   Top-Right Theme Switch Switcher
   ========================================================================== */

.theme-switch-wrapper {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  padding: 0.3rem 0.6rem;
  border-radius: var(--radius-full);
  box-shadow: var(--shadow-sm);
}

.theme-label {
  display: flex;
  align-items: center;
  color: var(--text-muted);
  transition: color var(--transition-speed) ease;
}

.theme-switch {
  position: relative;
  display: inline-block;
  width: 44px;
  height: 24px;
}

.theme-switch input {
  opacity: 0;
  width: 0;
  height: 0;
}

.slider {
  position: absolute;
  cursor: pointer;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  border-radius: 34px;
}

.slider:before {
  position: absolute;
  content: "";
  height: 16px;
  width: 16px;
  left: 3px;
  bottom: 3px;
  background-color: var(--text-primary);
  transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  border-radius: 50%;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
}

/* Checked state = Light mode (if checkbox represents Light) or vice-versa */
input:checked + .slider {
  background-color: var(--accent-color);
}

input:checked + .slider:before {
  transform: translateX(20px);
  background-color: #ffffff;
}

/* ==========================================================================
   Main Fullscreen Timer Stage
   ========================================================================== */

.timer-stage {
  flex: 1;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  width: 100%;
  height: 100%;
  padding: 4rem 1.5rem 2rem;
  position: relative;
}

/* Top Progress Bar Indicator */
.progress-bar-container {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 5px;
  background: var(--border-color);
  z-index: 100;
  overflow: hidden;
}

.progress-bar {
  height: 100%;
  width: 100%;
  background: var(--accent-color);
  box-shadow: 0 0 12px var(--progress-glow);
  transition: width 0.1s linear, background-color 0.4s ease, box-shadow 0.4s ease;
}

/* --- Dynamic Top Progress Bar Glow Phases --- */

/* Calm / Normal Phase (> 40% time remaining) */
body.timer-phase-calm .progress-bar {
  background: var(--accent-color);
  box-shadow: 0 0 12px var(--progress-glow);
}

/* Warning / Mid-Countdown Phase (15% - 40% time remaining) */
body.timer-phase-warning .progress-bar {
  background: #f59e0b;
  box-shadow: 0 0 16px rgba(245, 158, 11, 0.85);
}

/* Critical Urgency Phase (< 15% or last 10 seconds) - Vibrant Pulsing Glow */
body.timer-phase-critical .progress-bar {
  background: #ef4444;
  animation: top-bar-pulse 0.8s infinite alternate ease-in-out;
}

@keyframes top-bar-pulse {
  0% {
    box-shadow: 0 0 10px rgba(239, 68, 68, 0.7);
    opacity: 0.85;
  }
  100% {
    box-shadow: 0 0 24px rgba(239, 68, 68, 1), 0 0 6px #ffffff;
    opacity: 1;
  }
}

/* Completion Phase */
body.timer-finished .progress-bar {
  background: #10b981;
  box-shadow: 0 0 25px rgba(16, 185, 129, 0.95);
}

/* ==========================================================================
   Central Fullscreen Time Display
   ========================================================================== */

.display-container {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  margin-bottom: 2rem;
  cursor: pointer;
}

.time-display {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: clamp(0.5rem, 1.5vw, 2.5rem);
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.04em;
  color: var(--text-primary);
  text-shadow: 0 0 40px var(--digit-glow);
  transition: color var(--transition-speed) ease, transform 0.2s ease;
}

.time-segment {
  display: flex;
  flex-direction: column;
  align-items: center;
  position: relative;
  padding: 0.5rem 0.75rem;
  border-radius: var(--radius-lg);
  transition: all 0.2s ease;
}

.time-segment:hover {
  background: var(--bg-secondary);
  box-shadow: 0 0 0 1px var(--border-color);
  transform: scale(1.03);
}

.time-segment:focus-visible {
  outline: 2px solid var(--accent-color);
  outline-offset: 4px;
}

.digits {
  /* Fluid responsive font size scaling to maximize viewport */
  font-size: clamp(3.5rem, 14vw, 17vh);
  display: inline-block;
  min-width: 2ch;
  text-align: center;
}

.separator {
  font-size: clamp(3rem, 11vw, 14vh);
  color: var(--text-muted);
  margin-top: -0.8rem;
  opacity: 0.7;
  user-select: none;
  animation: pulse-colon 2s infinite ease-in-out;
}

@keyframes pulse-colon {
  0%, 100% { opacity: 0.7; }
  50% { opacity: 0.3; }
}

.segment-label {
  font-family: var(--font-sans);
  font-size: clamp(0.6rem, 1vw, 0.85rem);
  font-weight: 600;
  letter-spacing: 0.18em;
  color: var(--text-muted);
  margin-top: 0.5rem;
  text-transform: uppercase;
}

.edit-hint {
  margin-top: 1.25rem;
  font-size: 0.85rem;
  color: var(--text-muted);
  opacity: 0;
  transform: translateY(6px);
  transition: all 0.3s ease;
}

.display-container:hover .edit-hint {
  opacity: 1;
  transform: translateY(0);
}

.edit-hint kbd {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  padding: 0.15rem 0.4rem;
  border-radius: 4px;
  font-family: var(--font-mono);
  font-size: 0.75rem;
}

/* ==========================================================================
   Primary Controls Panel
   ========================================================================== */

.controls-panel {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1.25rem;
  margin-bottom: 1.75rem;
  z-index: 20;
  transition: opacity 0.4s ease, transform 0.4s ease;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.6rem;
  font-family: var(--font-sans);
  font-weight: 600;
  font-size: 1rem;
  padding: 0.85rem 1.6rem;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  outline: none;
  border: none;
}

.btn:active {
  transform: scale(0.97);
}

.btn-primary {
  background: var(--primary-btn-bg);
  color: var(--primary-btn-text);
  box-shadow: var(--shadow-sm);
  min-width: 140px;
  font-size: 1.05rem;
}

.btn-primary:hover {
  background: var(--primary-btn-hover);
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

.btn-secondary {
  background: var(--control-btn-bg);
  color: var(--text-primary);
  border: 1px solid var(--control-btn-border);
}

.btn-secondary:hover {
  background: var(--control-btn-hover);
  border-color: var(--border-focus);
  transform: translateY(-2px);
}

/* ==========================================================================
   Quick Presets Ribbon
   ========================================================================== */

.presets-container {
  display: flex;
  align-items: center;
  justify-content: center;
  flex-wrap: wrap;
  gap: 0.5rem;
  max-width: 800px;
  margin-bottom: 1.5rem;
  transition: opacity 0.4s ease;
}

.preset-title {
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text-muted);
  margin-right: 0.35rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.preset-chip {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  font-family: var(--font-mono);
  font-size: 0.85rem;
  font-weight: 600;
  padding: 0.4rem 0.85rem;
  border-radius: var(--radius-full);
  cursor: pointer;
  transition: all 0.2s ease;
  outline: none;
}

.preset-chip:hover {
  color: var(--text-primary);
  background: var(--bg-tertiary);
  border-color: var(--border-focus);
  transform: translateY(-1px);
}

.preset-chip.active {
  background: var(--accent-color);
  color: #ffffff;
  border-color: var(--accent-color);
  box-shadow: 0 2px 8px var(--accent-glow);
}

/* ==========================================================================
   Footer Shortcuts Info
   ========================================================================== */

.footer-info {
  display: flex;
  justify-content: center;
  align-items: center;
  padding-bottom: 0.5rem;
  transition: opacity 0.4s ease;
}

.shortcut-tags {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 1.25rem;
  font-size: 0.75rem;
  color: var(--text-muted);
}

.shortcut-tags span {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
}

.shortcut-tags kbd {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  padding: 0.15rem 0.45rem;
  border-radius: 4px;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  font-weight: 600;
}

/* ==========================================================================
   Idle & Running Mode (Fade Out Chrome for Immersion)
   ========================================================================== */

body.is-running.is-idle .top-bar,
body.is-running.is-idle .controls-panel,
body.is-running.is-idle .presets-container,
body.is-running.is-idle .footer-info {
  opacity: 0.12;
  pointer-events: auto;
}

body.is-running.is-idle .top-bar:hover,
body.is-running.is-idle .controls-panel:hover,
body.is-running.is-idle .presets-container:hover,
body.is-running.is-idle .footer-info:hover {
  opacity: 1;
}

/* ==========================================================================
   Modal / Dialog for Setting Time
   ========================================================================== */

.time-dialog {
  border: none;
  border-radius: var(--radius-lg);
  background: transparent;
  padding: 0;
  max-width: 480px;
  width: 90%;
  margin: auto;
  box-shadow: var(--shadow-lg);
  outline: none;
}

.time-dialog::backdrop {
  background: rgba(0, 0, 0, 0.65);
  backdrop-filter: blur(8px);
}

.dialog-content {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 2rem;
  color: var(--text-primary);
}

.dialog-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1.5rem;
}

.dialog-header h2 {
  font-size: 1.25rem;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.dialog-close-btn {
  background: transparent;
  border: none;
  font-size: 1.75rem;
  line-height: 1;
  color: var(--text-muted);
  cursor: pointer;
  padding: 0.2rem 0.5rem;
  border-radius: var(--radius-sm);
  transition: color 0.2s ease;
}

.dialog-close-btn:hover {
  color: var(--text-primary);
}

.time-inputs-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1.5rem;
}

.input-group {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
}

.input-group label {
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-muted);
}

.number-stepper {
  display: flex;
  flex-direction: column;
  align-items: center;
  background: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  overflow: hidden;
}

.number-stepper input {
  width: 72px;
  height: 52px;
  background: transparent;
  border: none;
  font-family: var(--font-mono);
  font-size: 1.75rem;
  font-weight: 700;
  color: var(--text-primary);
  text-align: center;
  outline: none;
  -moz-appearance: textfield;
}

.number-stepper input::-webkit-outer-spin-button,
.number-stepper input::-webkit-inner-spin-button {
  -webkit-appearance: none;
  margin: 0;
}

.step-btn {
  width: 100%;
  height: 28px;
  background: transparent;
  border: none;
  color: var(--text-secondary);
  font-size: 1.1rem;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: background 0.15s ease, color 0.15s ease;
}

.step-btn:hover {
  background: var(--border-color);
  color: var(--text-primary);
}

.colon-divider {
  font-family: var(--font-mono);
  font-size: 2rem;
  font-weight: 700;
  color: var(--text-muted);
  margin-top: 1.25rem;
}

.dialog-quick-presets {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  justify-content: center;
  margin-bottom: 1.75rem;
}

.quick-btn {
  background: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  padding: 0.35rem 0.75rem;
  border-radius: var(--radius-full);
  font-size: 0.8rem;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.2s ease;
}

.quick-btn:hover {
  color: var(--text-primary);
  border-color: var(--border-focus);
}

.dialog-actions {
  display: flex;
  justify-content: flex-end;
  gap: 0.75rem;
}

/* ==========================================================================
   Finish Banner / Alert
   ========================================================================== */

.finish-banner {
  position: fixed;
  bottom: 2.5rem;
  left: 50%;
  transform: translateX(-50%);
  background: var(--bg-secondary);
  border: 1px solid var(--accent-color);
  box-shadow: 0 12px 35px var(--accent-glow), var(--shadow-lg);
  border-radius: var(--radius-lg);
  padding: 1.25rem 1.75rem;
  z-index: 1000;
  animation: slide-up 0.4s cubic-bezier(0.16, 1, 0.3, 1), timer-pulse 1.5s infinite alternate;
}

@keyframes slide-up {
  from {
    opacity: 0;
    transform: translate(-50%, 30px);
  }
  to {
    opacity: 1;
    transform: translate(-50%, 0);
  }
}

@keyframes timer-pulse {
  from {
    box-shadow: 0 0 15px var(--accent-glow);
  }
  to {
    box-shadow: 0 0 35px var(--accent-glow);
  }
}

.finish-content {
  display: flex;
  align-items: center;
  gap: 1.25rem;
}

.finish-icon {
  font-size: 2rem;
}

.finish-text h3 {
  font-size: 1.1rem;
  font-weight: 700;
  margin-bottom: 0.2rem;
}

.finish-text p {
  font-size: 0.85rem;
  color: var(--text-secondary);
}

.finish-actions {
  display: flex;
  gap: 0.5rem;
  margin-left: 0.75rem;
}

/* Completion Screen Flash */
body.timer-finished {
  animation: screen-flash 1s infinite alternate;
}

@keyframes screen-flash {
  0% {
    background-color: var(--bg-primary);
  }
  100% {
    background-color: var(--bg-tertiary);
  }
}

/* ==========================================================================
   Responsive Adaptations
   ========================================================================== */

@media (max-width: 768px) {
  .top-bar {
    padding: 1rem 1.25rem;
  }
  
  .time-display {
    gap: 0.3rem;
  }
  
  .time-segment {
    padding: 0.25rem 0.35rem;
  }
  
  .separator {
    margin-top: -0.4rem;
  }
  
  .controls-panel {
    gap: 0.75rem;
  }
  
  .btn {
    padding: 0.75rem 1.2rem;
    font-size: 0.9rem;
  }
  
  .btn-primary {
    min-width: 110px;
  }
  
  .presets-container {
    gap: 0.35rem;
  }
  
  .preset-chip {
    padding: 0.3rem 0.65rem;
    font-size: 0.75rem;
  }
  
  .shortcut-tags {
    display: none;
  }
  
  .finish-content {
    flex-direction: column;
    text-align: center;
  }
  
  .finish-actions {
    margin-left: 0;
    margin-top: 0.5rem;
  }
}