/* ── CSS Variables ──────────────────────────────────────── */

:root {
  /* Colors */
  --color-primary: #4A90D9;
  --color-primary-hover: #357ABD;
  --color-danger: #E74C3C;
  --color-danger-hover: #C0392B;
  --color-success: #2ECC71;
  --color-warning: #F39C12;
  --color-bg: #FFFFFF;
  --color-bg-secondary: #F5F6F8;
  --color-text: #2C3E50;
  --color-text-secondary: #7F8C8D;
  --color-border: #E0E0E0;

  /* Status colors */
  --status-todo: #95A5A6;
  --status-in-progress: #3498DB;
  --status-done: #2ECC71;

  /* Priority colors */
  --priority-low: #95A5A6;
  --priority-medium: #F39C12;
  --priority-high: #E74C3C;

  /* Spacing */
  --space-xs: 4px;
  --space-sm: 8px;
  --space-md: 12px;
  --space-lg: 16px;
  --space-xl: 24px;

  /* Typography */
  --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Microsoft JhengHei', sans-serif;
  --font-size-xs: 11px;
  --font-size-sm: 12px;
  --font-size-md: 14px;
  --font-size-lg: 16px;

  /* Layout */
  --header-height: 48px;
  --tab-bar-height: 52px;
  --border-radius: 6px;
  --border-radius-sm: 4px;
}

/* ── Reset ──────────────────────────────────────────────── */

*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

/* ── Base ───────────────────────────────────────────────── */

html, body {
  width: 100%;
  height: 100%;
  font-family: var(--font-family);
  font-size: var(--font-size-md);
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.5;
  overflow: hidden;
}

#app {
  display: flex;
  flex-direction: column;
  height: 100vh;
}

#header {
  flex-shrink: 0;
}

#tab-bar {
  flex-shrink: 0;
}

#content {
  flex: 1;
  overflow-y: auto;
  padding: var(--space-md);
}

#content::-webkit-scrollbar {
  width: 6px;
}

#content::-webkit-scrollbar-track {
  background: transparent;
}

#content::-webkit-scrollbar-thumb {
  background: var(--color-border);
  border-radius: 3px;
}

#content::-webkit-scrollbar-thumb:hover {
  background: var(--color-text-secondary);
}

/* ── Header ─────────────────────────────────────────────── */

.header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--header-height);
  padding: 0 var(--space-md);
  border-bottom: 1px solid var(--color-border);
  background: var(--color-bg);
}

.header-left {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  min-width: 0;
}

.header-title {
  font-size: var(--font-size-lg);
  font-weight: 600;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: var(--space-xs);
  flex-shrink: 0;
}

/* ── Loading ────────────────────────────────────────────── */

.loading {
  display: flex;
  justify-content: center;
  align-items: center;
  padding: var(--space-xl);
}

.spinner {
  width: 24px;
  height: 24px;
  border: 3px solid var(--color-border);
  border-top-color: var(--color-primary);
  border-radius: 50%;
  animation: spin 0.6s linear infinite;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

/* ── Toast ──────────────────────────────────────────────── */

#toast-container {
  position: fixed;
  bottom: var(--space-md);
  left: 50%;
  transform: translateX(-50%);
  z-index: 1000;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-sm);
  pointer-events: none;
}

.toast {
  padding: var(--space-sm) var(--space-lg);
  border-radius: var(--border-radius);
  font-size: var(--font-size-sm);
  color: #fff;
  opacity: 0;
  transform: translateY(10px);
  transition: opacity 0.2s, transform 0.2s;
  pointer-events: auto;
}

.toast-show {
  opacity: 1;
  transform: translateY(0);
}

.toast-success { background: var(--color-success); }
.toast-error   { background: var(--color-danger); }
.toast-info    { background: var(--color-primary); }

body.has-tab-bar #toast-container {
  bottom: calc(var(--tab-bar-height) + var(--space-md));
}

/* ── Utility classes ────────────────────────────────────── */

.text-secondary { color: var(--color-text-secondary); }
.text-danger    { color: var(--color-danger); }
.text-success   { color: var(--color-success); }
.text-sm        { font-size: var(--font-size-sm); }
.text-xs        { font-size: var(--font-size-xs); }
.text-center    { text-align: center; }
.font-bold      { font-weight: 600; }

.p-sm  { padding: var(--space-sm); }
.p-md  { padding: var(--space-md); }
.p-lg  { padding: var(--space-lg); }
.mt-sm { margin-top: var(--space-sm); }
.mt-md { margin-top: var(--space-md); }
.mt-lg { margin-top: var(--space-lg); }
.mb-sm { margin-bottom: var(--space-sm); }
.mb-md { margin-bottom: var(--space-md); }
.mb-lg { margin-bottom: var(--space-lg); }

.flex        { display: flex; }
.flex-col    { flex-direction: column; }
.items-center { align-items: center; }
.justify-between { justify-content: space-between; }
.gap-xs { gap: var(--space-xs); }
.gap-sm { gap: var(--space-sm); }
.gap-md { gap: var(--space-md); }

.truncate {
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.hidden { display: none !important; }

/* ── Login page ─────────────────────────────────────────── */

.login-page {
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: var(--space-xl) var(--space-lg);
}

.login-brand {
  text-align: center;
  margin-bottom: var(--space-xl);
}

.login-logo {
  width: 64px;
  height: 64px;
  margin: 0 auto var(--space-md);
  background: var(--color-primary);
  color: #fff;
  font-size: 32px;
  font-weight: 700;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
}

.login-title {
  font-size: 20px;
  font-weight: 700;
  margin-bottom: var(--space-xs);
}

.login-form {
  width: 100%;
}

/* ── Project color dot ──────────────────────────────────── */

.project-color {
  width: 12px;
  height: 12px;
  border-radius: 50%;
  display: inline-block;
  flex-shrink: 0;
}

.flex-shrink-0 { flex-shrink: 0; }

/* ── Transitions & Animations ───────────────────────────── */

.card,
.list-item,
.btn,
.btn-sm,
.btn-icon {
  transition: background 0.15s ease, opacity 0.15s ease, transform 0.1s ease;
}

.btn:active:not(:disabled),
.btn-sm:active:not(:disabled) {
  transform: scale(0.97);
}

/* Focus styles for keyboard navigation */
.btn:focus-visible,
.btn-sm:focus-visible,
.btn-icon:focus-visible,
.form-input:focus-visible,
.form-select:focus-visible,
.form-textarea:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

/* ── Network status bar ─────────────────────────────────── */

.network-error {
  background: var(--color-danger);
  color: #fff;
  text-align: center;
  padding: var(--space-xs);
  font-size: var(--font-size-xs);
}