/* ───────────────────────────────
   Modern CSS Reset
──────────────────────────────── */
*,
*::before,
*::after {
  box-sizing: border-box;
}
* {
  margin: 0;
  padding: 0;
}
html:focus-within {
  scroll-behavior: smooth;
}
body {
  text-rendering: optimizeSpeed;
  line-height: 1.5;
}
a:not([class]) {
  text-decoration-skip-ink: auto;
}
img,
picture {
  max-width: 100%;
  display: block;
}
input,
button,
textarea,
select {
  font: inherit;
}
@media (prefers-reduced-motion: reduce) {
  * {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}

/* ───────────────────────────────
  Theme Variables (Light / Dark)
──────────────────────────────── */
:root {
  --font: 'Inter', system-ui, sans-serif;
  --bg: #ffffff;
  --text: #111827;
  --muted: #6b7280;
  --accent: #263470ab;
  --accent-hover: #253663;
  --border: #e5e7eb;
  --radius: 0.5rem;
  --error: #ef4444;
  --success: #22c55e;
}
body.dark-mode {
  --bg: #0f172a;
  --text: #f1f5f9;
  --muted: #94a3b8;
  --accent: #3b82f6;
  --accent-hover: #2563eb;
  --border: #334155;
}

/* ───────────────────────────────
  Base Styles
──────────────────────────────── */
body {
  font-family: var(--font);
  background-color: var(--bg);
  color: var(--text);
  min-height: 100vh;
}
.container {
  max-width: 720px;
  margin: auto;
  padding: 2rem 1rem;
}
header,
footer {
  background: var(--bg);
  border-bottom: 1px solid var(--border);
}
header .container,
footer .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
}
h1 a {
  text-decoration: none;
  color: var(--text);
}
h3 {
  margin: 20px 0px;
}
nav a {
  margin-left: 1rem;
  text-decoration: none;
  color: var(--text);
  font-weight: 500;
}
nav a:hover {
  color: var(--accent);
}

/* ───────────────────────────────
  Nav + Theme + Hamburger
──────────────────────────────── */
.header-container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
}
.nav-links {
  display: flex;
  gap: 1rem;
}
.header-actions {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}
.toggle-theme {
  background: transparent;
  border: none;
  font-size: 1.25rem;
  cursor: pointer;
  color: var(--text);
}
.toggle-theme:hover {
  background: transparent;
  transform: scale(1.07);
}
.hamburger {
  display: none;
  font-size: 1.5rem;
  background: none;
  border: none;
  color: var(--text);
  cursor: pointer;
}

.hamburger svg {
  width: 24px;
  height: 24px;
}

.hamburger:hover {
  background: transparent;
}
.mobile-menu {
  display: none;
  background: var(--bg);
  border-top: 1px solid var(--border);
  padding: 1rem;
}
.mobile-menu nav {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}
.mobile-menu.show {
  display: block;
}

/* ───────────────────────────────
  Forms
──────────────────────────────── */
.heading {
  text-align: center;
}
.auth-route {
  text-align: center;
}
.auth-route > a {
  color: #94a3b8;
}
form {
  margin: auto;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  margin-bottom: 2rem;
  width: 100%;
  max-width: 500px;
}
form.inline-form {
  flex-direction: row;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.5rem;
  margin: 0;
}
form.task-form {
  display: flex;
  flex-direction: row;
  gap: 0.5rem;
  align-items: center;
  margin-bottom: 2rem;
}
form.task-form input[type="text"] {
  flex: 1;
  padding: 0.5rem 0.75rem;
  font-size: 0.95rem;
}
input[type="text"],
input[type="password"],
textarea {
  padding: 0.65rem 0.75rem;
  font-size: 1rem;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: transparent;
  color: var(--text);
  width: 100%;
  box-sizing: border-box;
}
input:focus,
textarea:focus {
  outline: 2px solid var(--accent);
  outline-offset: 1px;
}
button,
input[type="submit"] {
  background: var(--accent);
  color: white;
  border: none;
  padding: 0.6rem 1rem;
  border-radius: var(--radius);
  cursor: pointer;
  font-weight: 600;
  transition: background 0.2s ease, transform 0.1s ease;
}
button:hover,
input[type="submit"]:hover {
  background: var(--accent-hover);
  transform: scale(1.03);
}

/* ───────────────────────────────
  Task Styles And Animations
──────────────────────────────── */
.task-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.75rem 1rem;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--bg);
  margin-bottom: 0.5rem;
  animation: fadeIn 0.3s ease-in;
}
.task-item form {
  margin: 0;
}
.task-item span {
  flex: 1;
}
.task-item.done span {
  text-decoration: line-through;
  opacity: 0.6;
}
.task-item button {
  background: transparent;
  border: none;
  padding: 0.4rem;
  cursor: pointer;
  color: var(--accent);
  transition: transform 0.1s ease;
}
.task-item button:hover {
  transform: scale(1.1);
}
@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}
@keyframes fadeOut {
  to {
    opacity: 0;
    transform: translateY(-10px);
    height: 0;
    margin: 0;
    padding: 0;
  }
}

/* ───────────────────────────────
  Messages
──────────────────────────────── */
.flash-messages {
  list-style: none;
  padding: 0;
  margin-top: 1rem;
}
.flash {
  position: relative;
  padding: 1rem;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  margin-bottom: 1rem;
  background-color: #fef3c7;
}
.flash.success {
  background-color: #dcfce7;
  color: #166534;
}
.flash.error {
  background-color: #fee2e2;
  color: #991b1b;
}
.flash .close-btn {
  position: absolute;
  top: 0.5rem;
  right: 0.75rem;
  background: transparent;
  border: none;
  font-size: 1.25rem;
  color: inherit;
  cursor: pointer;
}

/* ───────────────────────────────
  Responsive
──────────────────────────────── */
@media (max-width: 768px) {
  .desktop-nav {
    display: none;
  }
  .hamburger {
    display: inline;
  }
  .mobile-menu.show {
    display: block;
  }
}
@media (max-width: 600px) {
  header .container {
    flex-direction: flex;
    align-items: center;
    justify-content: space-between;
  }
  .nav-actions {
    width: 100%;
    flex-direction: column;
    align-items: flex-end;
    gap: 0.5rem;
    margin-top: 0.5rem;
  }
  nav {
    width: 100%;
    display: flex;
    justify-content: flex-end;
    gap: 0.75rem;
    flex-wrap: wrap;
  }
  .task-item {
    flex-direction: column;
    align-items: flex-start;
  }
  form.task-form {
    flex-direction: column;
    align-items: stretch;
  }
  button,
  input[type="submit"] {
    width: 100%;
  }
}