:root {
  --google-blue: #4285f4;
  --google-red: #ea4335;
  --google-yellow: #fbbc05;
  --google-green: #34a853;
  --surface: #ffffff;
  --background: #f1f3f4;
  --text: #202124;
  --subtle: #5f6368;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: 'Roboto', sans-serif;
  color: var(--text);
  background: radial-gradient(circle at top right, #e8f0fe, var(--background));
  min-height: 100vh;
}

.app-shell {
  max-width: 900px;
  margin: 24px auto;
  padding: 24px;
}

.topbar {
  background: var(--surface);
  border-radius: 20px;
  padding: 24px;
  box-shadow: 0 8px 24px rgba(60, 64, 67, 0.12);
  margin-bottom: 16px;
  border-top: 4px solid var(--google-blue);
}

.topbar h1 {
  margin: 0;
  font-size: 2rem;
}

.topbar p {
  margin: 8px 0 0;
  color: var(--subtle);
}


.auth-panel {
  margin-bottom: 16px;
}

.auth-panel h2 {
  margin: 0 0 4px;
}

.auth-copy {
  margin: 0 0 12px;
  color: var(--subtle);
}

.auth-controls {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.auth-controls input {
  border: 1px solid #dadce0;
  border-radius: 10px;
  padding: 8px 10px;
  min-width: 180px;
  font-size: 0.95rem;
  font-family: inherit;
}

.auth-user,
.auth-status {
  margin: 10px 0 0;
  color: var(--subtle);
  font-size: 0.95rem;
}

.page-tabs {
  display: flex;
  gap: 10px;
  margin-bottom: 16px;
  flex-wrap: wrap;
}

button,
.tab-button {
  border: none;
  border-radius: 14px;
  background: #e8f0fe;
  color: #174ea6;
  padding: 10px 14px;
  font-size: 1rem;
  font-weight: 500;
  cursor: pointer;
  position: relative;
  overflow: hidden;
  transition: transform 0.15s ease, box-shadow 0.2s ease, background-color 0.2s ease;
}

button:hover,
.tab-button:hover {
  transform: translateY(-1px);
  box-shadow: 0 6px 14px rgba(66, 133, 244, 0.25);
}

button:active,
.tab-button:active {
  transform: translateY(0);
}

.tab-button {
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.tab-button.active {
  background: var(--google-blue);
  color: white;
}

.page {
  display: none;
  animation: fadeIn 220ms ease;
}

.page.active {
  display: block;
}

@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(6px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.calculator-shell,
.card {
  background: var(--surface);
  border-radius: 20px;
  box-shadow: 0 8px 24px rgba(60, 64, 67, 0.12);
  padding: 20px;
}

#calc-display {
  width: 100%;
  font-size: 2rem;
  text-align: right;
  border: none;
  background: #f8f9fa;
  border-radius: 14px;
  padding: 14px;
  margin-bottom: 14px;
}

.calc-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(55px, 1fr));
  gap: 10px;
}

.calc-grid button {
  background: #f1f3f4;
  color: var(--text);
  min-height: 52px;
}

.calc-grid .operator {
  background: #d2e3fc;
  color: #1967d2;
}

.calc-grid .action {
  background: #fce8e6;
  color: var(--google-red);
}

.calc-grid .equals {
  background: var(--google-green);
  color: white;
}

.wide {
  grid-column: span 2;
}

textarea {
  width: 100%;
  min-height: 180px;
  margin-top: 8px;
  border-radius: 14px;
  border: 1px solid #dadce0;
  padding: 12px;
  font-family: inherit;
  font-size: 1rem;
  resize: vertical;
}

.notes-actions {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-top: 12px;
}


.shared-note-link,
.shared-note-content {
  margin: 12px 0 0;
  color: var(--subtle);
  white-space: pre-wrap;
  word-break: break-word;
}

.shared-canvas-image {
  width: 100%;
  border: 2px solid #dadce0;
  border-radius: 14px;
  display: block;
  margin-top: 12px;
  background: #fff;
}


.shared-note-content {
  margin-top: 0;
  font-size: 1.05rem;
  line-height: 1.5;
}

#notes-status {
  color: var(--subtle);
  font-size: 0.95rem;
}

.timer-card {
  text-align: center;
}

.time {
  margin: 4px 0 16px;
  font-size: 4rem;
  font-weight: 700;
  color: #188038;
}


.timer-setup {
  display: flex;
  justify-content: center;
  align-items: center;
  flex-wrap: wrap;
  gap: 8px;
  margin: 0 0 12px;
}

.timer-setup label {
  color: var(--subtle);
  font-size: 0.95rem;
}

.timer-setup input {
  width: 84px;
  border: 1px solid #dadce0;
  border-radius: 10px;
  padding: 8px 10px;
  font-size: 1rem;
  font-family: inherit;
}

#timer-status {
  margin-top: 10px;
  display: inline-block;
  color: var(--subtle);
  font-size: 0.95rem;
}

.timer-controls,
.canvas-actions {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 10px;
}

.canvas-help {
  margin: 0 0 10px;
  color: var(--subtle);
}

.canvas-stage {
  width: 100%;
}

#draw-canvas {
  width: 100%;
  border: 2px solid #dadce0;
  border-radius: 14px;
  display: block;
  background: #fff;
  touch-action: none;
}

.canvas-actions {
  margin-top: 12px;
  align-items: center;
}


#canvas-stage:fullscreen {
  width: 100vw;
  height: 100vh;
  background: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
}

#canvas-stage:fullscreen #draw-canvas {
  width: min(100vw, 1600px);
  height: min(100vh, 900px);
  border: none;
  border-radius: 0;
}

#canvas-status {
  color: var(--subtle);
  font-size: 0.95rem;
}

.ripple {
  position: absolute;
  border-radius: 50%;
  transform: scale(0);
  animation: ripple 620ms linear;
  background-color: rgba(255, 255, 255, 0.65);
  pointer-events: none;
}

@keyframes ripple {
  to {
    transform: scale(4);
    opacity: 0;
  }
}

@media (max-width: 600px) {
  .app-shell {
    margin: 12px;
    padding: 8px;
  }

  .topbar,
  .calculator-shell,
  .card {
    border-radius: 16px;
  }

  .time {
    font-size: 3.2rem;
  }
}