/* ============================================
   styles.css — Todo App
   Light Professional Theme
   ============================================ */

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

:root {
  --bg:        #f1f5f9;
  --surface:   #ffffff;
  --border:    #e2e8f0;
  --border2:   #cbd5e1;
  --text:      #0f172a;
  --body:      #334155;
  --muted:     #64748b;
  --subtle:    #94a3b8;
  --accent:    #0f766e;
  --accent-d:  #0d5f58;
  --accent-l:  #f0fdfa;
  --radius:    12px;
  --font:      'Inter', 'Segoe UI', Arial, sans-serif;
  --shadow-s:  0 1px 3px rgba(0,0,0,0.06), 0 1px 2px rgba(0,0,0,0.04);
  --shadow-m:  0 4px 16px rgba(0,0,0,0.07), 0 2px 6px rgba(0,0,0,0.04);

  --high:      #dc2626;
  --high-bg:   #fef2f2;
  --high-bdr:  #fecaca;
  --medium:    #d97706;
  --medium-bg: #fffbeb;
  --medium-bdr:#fde68a;
  --low:       #16a34a;
  --low-bg:    #f0fdf4;
  --low-bdr:   #bbf7d0;
}

.sr-only {
  position: absolute; width: 1px; height: 1px;
  overflow: hidden; clip: rect(0,0,0,0); white-space: nowrap;
}

html, body { height: 100%; }

body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  -webkit-font-smoothing: antialiased;
}

/* ============================================
   LOGIN SCREEN
   ============================================ */
.login-screen {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 24px;
  background: linear-gradient(135deg, #f0fdfa 0%, #e0f2fe 50%, #f5f3ff 100%);
}

.login-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: 52px 44px;
  max-width: 400px;
  width: 100%;
  text-align: center;
  box-shadow: var(--shadow-m);
  animation: fadeUp 0.4s ease;
}

.login-icon { margin-bottom: 20px; }

.login-card h1 {
  font-size: 1.75rem;
  font-weight: 700;
  letter-spacing: -0.5px;
  color: var(--text);
  margin-bottom: 10px;
}

.login-subtitle {
  color: var(--muted);
  font-size: 0.88rem;
  line-height: 1.65;
  margin-bottom: 32px;
}

#usernameInput {
  width: 100%;
  padding: 12px 16px;
  font-size: 0.95rem;
  font-family: var(--font);
  color: var(--text);
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  outline: none;
  text-align: center;
  letter-spacing: 0.5px;
  margin-bottom: 12px;
  transition: border-color 0.2s, box-shadow 0.2s;
}
#usernameInput::placeholder { color: var(--subtle); }
#usernameInput:focus {
  background: var(--surface);
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(15,118,110,0.1);
}

#loginButton {
  width: 100%;
  padding: 12px;
  background: var(--accent);
  color: #fff;
  font-size: 0.95rem;
  font-weight: 600;
  font-family: var(--font);
  border: none;
  border-radius: var(--radius);
  cursor: pointer;
  margin-bottom: 18px;
  transition: background 0.2s, transform 0.15s, box-shadow 0.2s;
  box-shadow: 0 2px 10px rgba(15,118,110,0.2);
}
#loginButton:hover {
  background: var(--accent-d);
  transform: translateY(-1px);
  box-shadow: 0 4px 16px rgba(15,118,110,0.25);
}

.login-hint {
  font-size: 0.78rem;
  color: var(--subtle);
}

/* ============================================
   APP LAYOUT
   ============================================ */
.app {
  height: 100vh;
  display: flex;
  flex-direction: column;
  max-width: 680px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ===== HEADER ===== */
.app-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 24px 0 20px;
  border-bottom: 1px solid var(--border);
  flex-shrink: 0;
}

.header-left {
  display: flex;
  align-items: center;
  gap: 14px;
}

.header-right {
  display: flex;
  align-items: center;
  gap: 8px;
}

#themeToggle {
  padding: 7px 14px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px;
  color: var(--muted);
  font-size: 0.8rem;
  font-family: var(--font);
  font-weight: 500;
  cursor: pointer;
  transition: border-color 0.2s, color 0.2s;
  box-shadow: var(--shadow-s);
}
#themeToggle:hover { border-color: var(--border2); color: var(--text); }

.header-logo {
  width: 38px;
  height: 38px;
  border-radius: 10px;
  background: var(--accent);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-size: 1.1rem;
  font-weight: 700;
  flex-shrink: 0;
}

.app-title {
  font-size: 1.1rem;
  font-weight: 700;
  letter-spacing: -0.3px;
  color: var(--text);
  line-height: 1.2;
}

.app-user {
  font-size: 0.78rem;
  color: var(--muted);
  line-height: 1.2;
}

#logoutBtn {
  padding: 7px 14px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px;
  color: var(--muted);
  font-size: 0.8rem;
  font-family: var(--font);
  font-weight: 500;
  cursor: pointer;
  transition: border-color 0.2s, color 0.2s, box-shadow 0.2s;
  box-shadow: var(--shadow-s);
}
#logoutBtn:hover {
  border-color: var(--border2);
  color: var(--text);
  box-shadow: var(--shadow-m);
}

/* ===== DASHBOARD ===== */
.dashboard {
  display: flex;
  gap: 12px;
  padding: 16px 0 4px;
  flex-shrink: 0;
}

.dash-card {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 4px;
  padding: 14px 10px;
  border-radius: var(--radius);
  border: 1px solid transparent;
  transition: transform 0.15s, box-shadow 0.15s;
}
.dash-card:hover {
  transform: translateY(-1px);
  box-shadow: var(--shadow-m);
}

.dash-card.high   { background: var(--high-bg);   border-color: var(--high-bdr); }
.dash-card.medium { background: var(--medium-bg); border-color: var(--medium-bdr); }
.dash-card.low    { background: var(--low-bg);    border-color: var(--low-bdr); }

.dash-count {
  font-size: 1.8rem;
  font-weight: 800;
  line-height: 1;
  letter-spacing: -1px;
}
.dash-card.high   .dash-count { color: var(--high); }
.dash-card.medium .dash-count { color: var(--medium); }
.dash-card.low    .dash-count { color: var(--low); }

.dash-label {
  font-size: 0.7rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 1px;
}
.dash-card.high   .dash-label { color: var(--high); }
.dash-card.medium .dash-label { color: var(--medium); }
.dash-card.low    .dash-label { color: var(--low); }

/* ===== ADD TASK BAR ===== */
.add-task-bar {
  display: flex;
  gap: 10px;
  padding: 20px 0 16px;
  flex-shrink: 0;
}

#todoInput {
  flex: 1;
  padding: 11px 16px;
  font-size: 0.92rem;
  font-family: var(--font);
  color: var(--text);
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  outline: none;
  box-shadow: var(--shadow-s);
  transition: border-color 0.2s, box-shadow 0.2s;
}
#todoInput::placeholder { color: var(--subtle); }
#todoInput:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(15,118,110,0.1);
}

#prioritySelect {
  padding: 11px 12px;
  font-size: 0.82rem;
  font-family: var(--font);
  color: var(--body);
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  outline: none;
  cursor: pointer;
  flex-shrink: 0;
  box-shadow: var(--shadow-s);
  transition: border-color 0.2s;
}
#prioritySelect:focus { border-color: var(--accent); }

#addButton {
  padding: 11px 22px;
  background: var(--accent);
  color: #fff;
  font-size: 0.88rem;
  font-weight: 600;
  font-family: var(--font);
  border: none;
  border-radius: var(--radius);
  cursor: pointer;
  white-space: nowrap;
  flex-shrink: 0;
  box-shadow: 0 2px 8px rgba(15,118,110,0.2);
  transition: background 0.2s, transform 0.15s, box-shadow 0.2s;
}
#addButton:hover {
  background: var(--accent-d);
  transform: translateY(-1px);
  box-shadow: 0 4px 14px rgba(15,118,110,0.25);
}
#addButton:active { transform: translateY(0); }

/* ===== TASK AREA ===== */
.task-area {
  flex: 1;
  display: flex;
  flex-direction: column;
  min-height: 0;
  padding-bottom: 24px;
}

.task-area-header {
  display: flex;
  align-items: center;
  gap: 8px;
  padding-bottom: 12px;
  flex-shrink: 0;
}

.task-area-title {
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 1.2px;
  color: var(--muted);
}

.task-count-badge {
  background: var(--accent);
  color: #fff;
  font-size: 0.7rem;
  font-weight: 700;
  padding: 1px 7px;
  border-radius: 999px;
  min-width: 20px;
  text-align: center;
}

.drag-hint {
  margin-left: auto;
  font-size: 0.72rem;
  color: var(--subtle);
  font-style: italic;
}

.state-msg {
  color: var(--muted);
  font-size: 0.88rem;
  text-align: center;
  padding: 40px 0;
}

/* ===== TASK LIST ===== */
#todoList {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 8px;
  overflow-y: auto;
  flex: 1;
  padding-right: 4px;
}

#todoList::-webkit-scrollbar { width: 4px; }
#todoList::-webkit-scrollbar-track { background: transparent; }
#todoList::-webkit-scrollbar-thumb { background: var(--border2); border-radius: 4px; }

/* ===== TASK ITEM ===== */
#todoList li {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 13px 16px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  border-left-width: 4px;
  font-size: 0.92rem;
  color: var(--text);
  box-shadow: var(--shadow-s);
  transition: box-shadow 0.15s, transform 0.15s, border-color 0.15s;
  animation: taskIn 0.22s ease;
  cursor: grab;
  user-select: none;
}
#todoList li:hover {
  box-shadow: var(--shadow-m);
  transform: translateY(-1px);
}
#todoList li:active { cursor: grabbing; }

#todoList li[data-priority="high"]   { border-left-color: var(--high); }
#todoList li[data-priority="medium"] { border-left-color: var(--medium); }
#todoList li[data-priority="low"]    { border-left-color: var(--low); }

#todoList li.dragging {
  opacity: 0.45;
  transform: scale(0.98);
  box-shadow: none;
}
#todoList li.drag-over {
  border-color: var(--accent);
  border-left-color: var(--accent);
  box-shadow: 0 0 0 2px rgba(15,118,110,0.15);
}

.drag-handle {
  color: var(--subtle);
  font-size: 1.1rem;
  flex-shrink: 0;
  cursor: grab;
  line-height: 1;
}

.priority-badge {
  font-size: 0.68rem;
  font-weight: 600;
  padding: 3px 9px;
  border-radius: 6px;
  flex-shrink: 0;
  text-transform: uppercase;
  letter-spacing: 0.4px;
  border: 1px solid transparent;
}
.priority-badge.high   { background: var(--high-bg);   color: var(--high);   border-color: var(--high-bdr); }
.priority-badge.medium { background: var(--medium-bg); color: var(--medium); border-color: var(--medium-bdr); }
.priority-badge.low    { background: var(--low-bg);    color: var(--low);    border-color: var(--low-bdr); }
.priority-badge:hover  { filter: brightness(0.92); transform: scale(1.05); transition: all 0.15s; }

.task-text {
  flex: 1;
  line-height: 1.4;
  font-weight: 400;
  color: var(--body);
}

.delete-btn {
  padding: 5px 11px;
  color: var(--subtle);
  background: transparent;
  border: 1px solid transparent;
  border-radius: 7px;
  font-size: 0.78rem;
  font-family: var(--font);
  font-weight: 500;
  cursor: pointer;
  flex-shrink: 0;
  transition: color 0.2s, border-color 0.2s, background 0.2s;
}
.delete-btn:hover {
  color: var(--high);
  border-color: var(--high-bdr);
  background: var(--high-bg);
}

/* ===== ANIMATIONS ===== */
@keyframes fadeUp {
  from { opacity: 0; transform: translateY(14px); }
  to   { opacity: 1; transform: translateY(0); }
}

@keyframes taskIn {
  from { opacity: 0; transform: translateX(-8px); }
  to   { opacity: 1; transform: translateX(0); }
}

/* ===== DARK MODE ===== */
body.dark-mode {
  --bg:        #09111e;
  --surface:   #0f1d30;
  --border:    rgba(255,255,255,0.08);
  --border2:   rgba(255,255,255,0.14);
  --text:      #f0f6ff;
  --body:      #b8cce0;
  --muted:     #7a9ab8;
  --subtle:    #4a6a88;
  --shadow-s:  0 1px 4px rgba(0,0,0,0.3);
  --shadow-m:  0 4px 16px rgba(0,0,0,0.4);
}

body.dark-mode .login-screen {
  background: radial-gradient(ellipse at 60% 40%, rgba(20,184,166,0.1) 0%, transparent 60%), #09111e;
}

body.dark-mode .login-card {
  background: #0f1d30;
  border-color: rgba(255,255,255,0.08);
}

body.dark-mode #usernameInput {
  background: #09111e;
  color: #f0f6ff;
  border-color: rgba(255,255,255,0.1);
}

body.dark-mode .dash-card.high   { background: rgba(220,38,38,0.12);  border-color: rgba(220,38,38,0.25); }
body.dark-mode .dash-card.medium { background: rgba(217,119,6,0.12);  border-color: rgba(217,119,6,0.25); }
body.dark-mode .dash-card.low    { background: rgba(22,163,74,0.12);  border-color: rgba(22,163,74,0.25); }

body.dark-mode #todoInput,
body.dark-mode #prioritySelect {
  background: #0f1d30;
  color: #f0f6ff;
  border-color: rgba(255,255,255,0.08);
}

body.dark-mode #todoList li {
  background: #0f1d30;
  border-color: rgba(255,255,255,0.08);
}
body.dark-mode #todoList li:hover { background: #14253d; }

body.dark-mode .priority-badge.high   { background: rgba(220,38,38,0.15);  border-color: rgba(220,38,38,0.3); }
body.dark-mode .priority-badge.medium { background: rgba(217,119,6,0.15);  border-color: rgba(217,119,6,0.3); }
body.dark-mode .priority-badge.low    { background: rgba(22,163,74,0.15);  border-color: rgba(22,163,74,0.3); }

body.dark-mode #themeToggle {
  background: #0f1d30;
  border-color: rgba(255,255,255,0.1);
  color: #7a9ab8;
}

/* ===== RESPONSIVE ===== */
@media (max-width: 500px) {
  .app { padding: 0 16px; }
  .add-task-bar { flex-wrap: wrap; }
  #prioritySelect { flex: 1; }
  #addButton { flex: 1; }
  .login-card { padding: 40px 28px; }
}