:root {
  --bg-1: #022243;
  --bg-2: #0c1017;
  --border: rgba(137, 159, 196, 0.3);
  --text: #eef3ff;
  --muted: #9aa9c2;
  --accent: #35b8ff;
  --accent-2: #74ffd3;
  --danger: #ff6e7f;
  --ok: #82f7b3;
  --shadow-lg: 0 20px 45px rgba(0, 0, 0, 0.45);
}

* {
  box-sizing: border-box;
}

html,
body {
  min-height: 100%;
}

body {
  margin: 0;
  color: var(--text);
  font-family: "Manrope", "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
  line-height: 1.45;
  letter-spacing: 0.01em;
  background:
    radial-gradient(1200px 500px at 10% -10%, rgba(53, 184, 255, 0.16), transparent 60%),
    radial-gradient(1000px 520px at 110% 0%, rgba(116, 255, 211, 0.12), transparent 55%),
    linear-gradient(180deg, var(--bg-2), var(--bg-1));
}

.app-shell {
  display: grid;
  grid-template-columns: 250px 1fr;
  min-height: 100vh;
}

.sidebar {
  border-right: 1px solid var(--border);
  background: linear-gradient(180deg, rgba(10, 15, 24, 0.95), rgba(12, 18, 29, 0.88));
  padding: 1.1rem;
  position: sticky;
  top: 0;
  height: 100vh;
}

.brand h1 {
  margin: 0;
  font-size: 1.25rem;
  font-weight: 800;
  letter-spacing: 0.02em;
}

.brand p {
  margin: 0.35rem 0 1rem;
  color: var(--muted);
  font-size: 0.86rem;
  line-height: 1.35;
}

.sidebar-nav {
  display: grid;
  gap: 0.45rem;
}

.nav-btn {
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 0.6rem 0.8rem;
  background: rgba(15, 21, 32, 0.95);
  color: var(--text);
  text-align: left;
  font-weight: 700;
  cursor: pointer;
  transition: transform 0.16s ease, border-color 0.16s ease, filter 0.16s ease;
}

.nav-btn.active {
  border-color: rgba(53, 184, 255, 0.65);
  background: linear-gradient(135deg, rgba(30, 98, 152, 0.55), rgba(18, 54, 88, 0.5));
}

.nav-btn:hover {
  transform: translateY(-1px);
  filter: brightness(1.06);
}

.main-content {
  display: grid;
  grid-template-rows: auto 1fr;
}

.topbar {
  background: linear-gradient(120deg, rgba(15, 22, 34, 0.95), rgba(22, 30, 46, 0.88));
  border-bottom: 1px solid var(--border);
  backdrop-filter: blur(8px);
  color: var(--text);
  padding: 1rem 1.25rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  position: sticky;
  top: 0;
  z-index: 20;
}

.topbar h2 {
  margin: 0;
  font-size: 1.45rem;
  font-weight: 800;
  letter-spacing: 0.01em;
}

.topbar p {
  margin: 0.25rem 0 0;
  color: var(--muted);
  font-size: 0.92rem;
  line-height: 1.35;
}

.add-class-btn,
.class-summary,
.remove-class-btn,
.item-form button,
.month-btn {
  position: relative;
  overflow: hidden;
  border-radius: 8px;
}

.add-class-btn {
  width: 52px;
  height: 52px;
  border-radius: 50%;
  border: 1px solid rgba(116, 255, 211, 0.5);
  background: radial-gradient(circle at 30% 20%, #39c9ff, #1779cc 75%);
  color: #02111d;
  font-size: 2rem;
  line-height: 1;
  cursor: pointer;
  box-shadow: 0 8px 22px rgba(23, 121, 204, 0.45);
  transition: transform 0.16s ease, filter 0.16s ease;
}

.add-class-btn:hover {
  transform: translateY(-1px) scale(1.02);
  filter: brightness(1.06);
}

.add-class-btn:disabled {
  opacity: 0.45;
  cursor: not-allowed;
}

.view {
  max-width: 1080px;
  width: 100%;
  margin: 1rem auto 2rem;
  padding: 0 1rem;
}

.view:not(.active) {
  display: none;
}

.dashboard-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 0.75rem;
}

.dashboard-header h3,
.calendar-header h3 {
  margin: 0;
  font-size: 1.15rem;
  font-weight: 750;
  letter-spacing: 0.01em;
}

.counter {
  font-weight: 600;
  color: var(--accent-2);
}

.class-card {
  border: 1px solid var(--border);
  border-radius: 14px;
  overflow: hidden;
  margin-bottom: 1rem;
  background: linear-gradient(160deg, rgba(24, 31, 45, 0.92), rgba(18, 24, 36, 0.86));
  box-shadow: var(--shadow-lg);
  transition: transform 0.18s ease, border-color 0.18s ease, box-shadow 0.18s ease;
  transform-style: preserve-3d;
}

.class-card:hover {
  border-color: rgba(116, 255, 211, 0.42);
  box-shadow: 0 24px 44px rgba(0, 0, 0, 0.52);
}

.class-summary {
  width: 100%;
  display: flex;
  justify-content: space-between;
  align-items: center;
  background: linear-gradient(90deg, rgba(27, 36, 53, 0.95), rgba(20, 27, 41, 0.95));
  border: 0;
  border-bottom: 1px solid var(--border);
  padding: 0.9rem 1rem;
  font-size: 1.05rem;
  cursor: pointer;
  color: var(--text);
  font-weight: 700;
  transition: filter 0.16s ease;
}

.class-summary:hover {
  filter: brightness(1.06);
}

.class-card.collapsed .chevron {
  transform: rotate(0deg);
}

.class-card:not(.collapsed) .chevron {
  transform: rotate(180deg);
}

.chevron {
  transition: transform 0.22s ease;
  color: var(--accent-2);
}

.class-content {
  padding: 1rem;
}

.class-meta {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
  margin-bottom: 1rem;
}

.class-meta label {
  display: grid;
  gap: 0.4rem;
  font-weight: 700;
  font-size: 0.92rem;
  min-width: min(350px, 100%);
}

.class-meta input,
.item-form input {
  padding: 0.58rem;
  border: 1px solid rgba(137, 159, 196, 0.35);
  border-radius: 8px;
  background: rgba(8, 12, 20, 0.95);
  color: var(--text);
  outline: none;
}

.remove-class-btn {
  background: rgba(255, 110, 127, 0.1);
  color: #ff95a1;
  border: 1px solid rgba(255, 110, 127, 0.45);
  padding: 0.6rem 0.9rem;
  height: fit-content;
  margin-top: auto;
  cursor: pointer;
  transition: transform 0.16s ease, background 0.16s ease;
}

.remove-class-btn:hover {
  transform: translateY(-1px);
  background: rgba(255, 110, 127, 0.18);
}

.grade-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem;
}

.grade-panel {
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 0.9rem;
  background: linear-gradient(160deg, rgba(16, 22, 33, 0.96), rgba(13, 18, 28, 0.92));
}

.grade-panel h4 {
  margin-top: 0;
  color: #d8ecff;
  border-bottom: 1px solid var(--border);
  padding-bottom: 0.5rem;
  font-size: 1rem;
  font-weight: 750;
}

.item-form {
  display: grid;
  grid-template-columns: 2fr 1fr auto;
  gap: 0.4rem;
  margin-bottom: 0.6rem;
}

.item-form button,
.month-btn {
  padding: 0.5rem 0.75rem;
  border: 1px solid rgba(53, 184, 255, 0.5);
  background: linear-gradient(135deg, #1f74c0, #12518a);
  color: #eef7ff;
  cursor: pointer;
  transition: transform 0.16s ease, filter 0.16s ease;
}

.item-form button:hover,
.month-btn:hover {
  transform: translateY(-1px);
  filter: brightness(1.08);
}

.item-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0.5rem;
}

.item-list li {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 0.75rem;
  background: rgba(7, 11, 18, 0.95);
  border: 1px solid rgba(137, 159, 196, 0.3);
  border-left: 4px solid #39c9ff;
  border-radius: 8px;
  padding: 0.55rem 0.7rem;
  font-size: 0.92rem;
  line-height: 1.3;
}

.item-name {
  flex: 1 1 auto;
}

.item-list .due-date {
  font-weight: 700;
  color: var(--ok);
  white-space: nowrap;
}

.item-done-btn {
  border: 1px solid rgba(130, 247, 179, 0.45);
  background: rgba(130, 247, 179, 0.12);
  color: #b0ffd3;
  border-radius: 6px;
  padding: 0.24rem 0.54rem;
  font-size: 0.75rem;
  cursor: pointer;
  white-space: nowrap;
  transition: transform 0.14s ease, background 0.14s ease;
}

.item-done-btn:hover {
  transform: translateY(-1px);
  background: rgba(130, 247, 179, 0.2);
}

.item-remove-btn {
  border: 1px solid rgba(255, 110, 127, 0.45);
  background: rgba(255, 110, 127, 0.12);
  color: #ff9eab;
  border-radius: 6px;
  padding: 0.24rem 0.54rem;
  font-size: 0.75rem;
  cursor: pointer;
  white-space: nowrap;
  transition: transform 0.14s ease, background 0.14s ease;
}

.item-remove-btn:hover {
  transform: translateY(-1px);
  background: rgba(255, 110, 127, 0.2);
}

.max-notice {
  min-height: 1.2rem;
  color: var(--danger);
  font-weight: 600;
}

.calendar-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 0.7rem;
}

.calendar-grid {
  display: grid;
  grid-template-columns: repeat(7, minmax(0, 1fr));
  gap: 0.55rem;
}

.day-header {
  text-align: center;
  font-weight: 700;
  color: var(--accent-2);
  padding: 0.35rem;
}

.calendar-cell {
  border: 1px solid var(--border);
  border-radius: 10px;
  background: rgba(9, 14, 22, 0.9);
  min-height: 122px;
  padding: 0.45rem;
  display: grid;
  grid-template-rows: auto 1fr;
  gap: 0.35rem;
}

.calendar-cell.muted {
  opacity: 0.45;
}

.calendar-date {
  font-weight: 700;
  font-size: 0.95rem;
}

.calendar-items {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0.3rem;
}

.calendar-items li {
  border-left: 3px solid var(--accent);
  background: rgba(18, 29, 42, 0.95);
  padding: 0.28rem 0.35rem;
  border-radius: 6px;
  font-size: 0.8rem;
  line-height: 1.2;
}

.calendar-items li.quiz {
  border-left-color: var(--accent-2);
}

.empty-calendar {
  text-align: center;
  color: var(--muted);
  padding: 1rem;
  border: 1px dashed var(--border);
  border-radius: 10px;
  grid-column: 1 / -1;
}

.completed-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0.55rem;
}

.completed-item {
  border: 1px solid var(--border);
  border-left: 4px solid var(--ok);
  border-radius: 10px;
  background: rgba(9, 14, 22, 0.9);
  padding: 0.6rem 0.7rem;
  display: grid;
  gap: 0.25rem;
}

.completed-name {
  font-weight: 700;
}

.completed-meta {
  color: var(--muted);
  font-size: 0.84rem;
}

.grade-calc-panel {
  margin-bottom: 1rem;
}

.grade-calc-top {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0.75rem;
  margin-bottom: 0.8rem;
}

.grade-calc-label {
  display: grid;
  gap: 0.35rem;
  font-size: 0.9rem;
  font-weight: 700;
}

.grade-calc-label input,
.grade-calc-label select {
  padding: 0.58rem;
  border: 1px solid rgba(137, 159, 196, 0.35);
  border-radius: 8px;
  background: rgba(8, 12, 20, 0.95);
  color: var(--text);
  outline: none;
}

.grade-help {
  margin: 0 0 0.55rem;
  color: #c1d3f3;
  font-size: 0.83rem;
  background: rgba(53, 184, 255, 0.1);
  border: 1px solid rgba(53, 184, 255, 0.35);
  border-radius: 999px;
  display: inline-block;
  padding: 0.2rem 0.55rem;
}

.grade-category-rows {
  display: grid;
  gap: 0.55rem;
  margin-bottom: 0.7rem;
}

.grade-category-row {
  display: grid;
  grid-template-columns: 1.5fr 0.8fr 1fr auto;
  gap: 0.5rem;
  align-items: center;
  border: 1px solid rgba(137, 159, 196, 0.32);
  border-radius: 12px;
  background: rgba(10, 15, 24, 0.85);
  padding: 0.45rem;
}

.grade-category-row input {
  padding: 0.46rem 0.52rem;
  border: 1px solid rgba(137, 159, 196, 0.35);
  border-radius: 8px;
  background: rgba(12, 19, 31, 0.95);
  color: #f2f7ff;
  font-size: 0.84rem;
  font-weight: 600;
  outline: none;
}

.grade-category-row .grade-cat-name {
  letter-spacing: 0.01em;
}

.grade-category-row .grade-cat-weight,
.grade-category-row .grade-cat-current {
  text-align: center;
  font-variant-numeric: tabular-nums;
}

.grade-category-row .item-remove-btn {
  padding: 0.36rem 0.6rem;
  font-size: 0.73rem;
  border-radius: 999px;
}

.grade-output {
  margin: 0.72rem 0 0;
  font-weight: 750;
  color: var(--accent-2);
  background: rgba(116, 255, 211, 0.08);
  border: 1px solid rgba(116, 255, 211, 0.3);
  border-radius: 10px;
  padding: 0.42rem 0.55rem;
}

.grade-calc-tools {
  margin-top: 0;
}

@media (max-width: 960px) {
  .app-shell {
    grid-template-columns: 1fr;
  }

  .sidebar {
    position: static;
    height: auto;
  }
}

@media (max-width: 760px) {
  .grade-grid {
    grid-template-columns: 1fr;
  }

  .item-form {
    grid-template-columns: 1fr;
  }

  .calendar-grid {
    grid-template-columns: 1fr;
  }

  .day-header {
    display: none;
  }

  .grade-calc-top {
    grid-template-columns: 1fr;
  }

  .grade-category-row {
    grid-template-columns: 1fr;
  }
}