:root {
  --primary: #818cf8; /* Lighter indigo for dark mode */
  --primary-hover: #a5b4fc;
  --bg: #0f172a; /* Deep slate */
  --sidebar-bg: #1e293b;
  --text: #f1f5f9;
  --text-muted: #94a3b8;
  --border: #334155;
  --card-bg: #1e293b;
  --shadow: 0 4px 6px -1px rgb(0 0 0 / 0.3), 0 2px 4px -2px rgb(0 0 0 / 0.3);
  --header-height: 80px;
  --sidebar-width: 280px;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background-color: var(--bg);
  color: var(--text);
  line-height: 1.5;
  overflow-x: hidden;
  width: 100%;
}

h1, h2, h3, h4, h5 {
  margin-top: 0;
  color: var(--text);
  font-weight: 600;
}

a {
  text-decoration: none;
  color: inherit;
}

.logo-link {
  display: block;
  width: fit-content;
}

/* Layout */
.app-container {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  overflow-x: hidden;
  width: 100%;
}

.app-header {
  height: var(--header-height);
  background-color: var(--sidebar-bg);
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 2rem;
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-ad {
  display: flex;
  align-items: center;
}

@media (max-width: 768px) {
  .header-ad {
    display: none;
  }
  
  .app-header {
    padding: 0 1rem;
    justify-content: flex-start; /* Ensure items start from left */
    width: 100%;
    overflow: hidden; /* Prevent ad or logo from causing scroll */
  }
}

.logo-container {
  display: flex;
  align-items: center;
}

.logoImg {
  background-image: url('../assets/images/logo/logo.svg');
  background-repeat: no-repeat;
  background-size: contain;
  width: 380px;
  height: 80px;
  display: block;
}

.main-layout {
  display: flex;
  flex: 1;
}

.sidebar {
  width: var(--sidebar-width);
  background-color: var(--sidebar-bg);
  border-right: 1px solid var(--border);
  padding: 1.5rem 0;
  overflow-y: auto;
  position: sticky;
  top: var(--header-height);
  height: calc(100vh - var(--header-height));
}

.content-area {
  flex: 1;
  padding: 2rem;
  max-width: 1200px;
  margin: 0 auto;
}

/* Sidebar Nav */
.nav-group {
  margin-bottom: 2rem;
}

.nav-title {
  padding: 0 1.5rem;
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-muted);
  margin-bottom: 0.5rem;
}

.nav-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.nav-link {
  display: block;
  padding: 0.625rem 1.5rem;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-muted);
  transition: all 0.2s;
  border-left: 3px solid transparent;
}

.nav-link:hover {
  background-color: var(--bg);
  color: var(--primary);
}

.nav-link.navLinkActive {
  color: var(--primary);
  background-color: rgba(129, 140, 248, 0.1);
  border-left-color: var(--primary);
}

/* Calc Card */
.calc-card {
  background-color: var(--card-bg);
  border-radius: 0.75rem;
  box-shadow: var(--shadow);
  padding: 2rem;
  margin-bottom: 2rem;
  max-width: 800px;
  margin-left: auto;
  margin-right: auto;
  border: 1px solid var(--border);
}

.calc-title {
  font-size: 1.5rem;
  margin-bottom: 1.5rem;
  border-bottom: 1px solid var(--border);
  padding-bottom: 1rem;
}

/* Custom Number Spinner */
.number-spinner {
  display: flex;
  align-items: center;
  max-width: 200px;
  border: 1px solid var(--border);
  border-radius: 0.5rem;
  overflow: hidden;
  background-color: var(--bg);
}

.number-spinner input[type="number"] {
  flex: 1;
  border: none;
  border-radius: 0;
  text-align: center;
  padding: 0.75rem 0.5rem;
  -moz-appearance: textfield;
  background-color: var(--bg);
  color: var(--text);
}

.number-spinner input::-webkit-outer-spin-button,
.number-spinner input::-webkit-inner-spin-button {
  -webkit-appearance: none;
  margin: 0;
}

.spinner-btn {
  background-color: var(--border);
  border: none;
  color: var(--text);
  padding: 0.75rem 1rem;
  font-size: 1.25rem;
  font-weight: 600;
  cursor: pointer;
  transition: background-color 0.2s;
  user-select: none;
}

.spinner-btn:hover {
  background-color: var(--text-muted);
  color: var(--bg);
}

.spinner-btn:active {
  background-color: var(--primary);
  color: white;
}

/* Forms */
.form-group {
  margin-bottom: 1.5rem;
}

label {
  display: block;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-muted);
  margin-bottom: 0.5rem;
}

input[type="number"], 
input[type="text"], 
select {
  width: auto;
  min-width: 80px;
  padding: 0.75rem 1rem;
  font-size: 1rem;
  border: 1px solid var(--border);
  border-radius: 0.5rem;
  background-color: var(--bg);
  color: var(--text);
  transition: border-color 0.2s, box-shadow 0.2s;
  outline: none;
}

/* Custom widths for specific inputs */
select#ConvertNoteA, 
select#NoteDiffInHertzA, 
select#NoteDiffInHertzC, 
select#SemitoneDifferenceA,
select#GenerateNoteHertzTableA {
  width: 100px;
}

select#ConvertNoteB, 
select#NoteDiffInHertzB, 
select#NoteDiffInHertzD, 
select#SemitoneDifferenceB,
select#GenerateNoteOctaveHertzTableA,
select#ConvertBWtoQA,
select#ConvertBWtoQB {
  width: 80px;
}

select#BpmDelayTimingC {
  width: 120px;
}

input:focus, select:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(129, 140, 248, 0.2);
}

.input-with-label {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.5rem;
}

/* Results */
.resultsTable {
  margin-top: 2rem;
  border-top: 2px solid var(--border);
  padding-top: 2rem;
}

.table {
  width: 100%;
  border-collapse: collapse;
}

.table td {
  padding: 0.75rem 0;
  border-bottom: 1px solid var(--border);
}

.table tr:last-child td {
  border-bottom: none;
}

.table strong {
  color: var(--text-muted);
  font-weight: 500;
}

.table span {
  font-family: 'JetBrains Mono', 'Courier New', monospace;
  font-weight: 600;
  color: var(--primary);
}

/* Vertical Table (Chart) */
.table thead td {
  font-weight: 700;
  color: var(--text);
  border-bottom: 2px solid var(--border);
}

/* Mobile Menu Toggle (Hamburger) */
.hamburger-btn {
  display: none;
  width: 28px;
  height: 20px;
  background: transparent;
  border: none;
  cursor: pointer;
  padding: 0;
  z-index: 1000;
  outline: none;
  position: relative;
}

.hamburger-btn span {
  display: block;
  position: absolute;
  width: 100%;
  height: 3px;
  background: var(--primary);
  border-radius: 3px;
  opacity: 1;
  left: 0;
  transform: rotate(0deg);
  transition: all 0.25s ease-in-out;
}

.hamburger-btn span:nth-child(1) { top: 0px; }
.hamburger-btn span:nth-child(2) { top: 8px; }
.hamburger-btn span:nth-child(3) { top: 16px; }

/* Hamburger active state (forming an X) */
.hamburger-btn.active span:nth-child(1) {
  top: 8px;
  transform: rotate(45deg);
}

.hamburger-btn.active span:nth-child(2) {
  opacity: 0;
  left: -20px;
}

.hamburger-btn.active span:nth-child(3) {
  top: 8px;
  transform: rotate(-45deg);
}

@media (max-width: 1024px) {
  --sidebar-width: 240px;
}

@media (max-width: 768px) {
  :root {
    --header-height: 60px;
  }

  .app-header {
    position: relative; /* Remove sticky */
    padding: 0 1rem;
    justify-content: flex-start;
    width: 100%;
    overflow: hidden;
  }

  .main-layout {
    flex-direction: column;
  }
  
  .sidebar {
    position: fixed;
    left: -100%;
    width: 100%;
    height: 100vh; /* Fill whole screen when open */
    top: 0;
    z-index: 1002; /* Above the header */
    transition: left 0.3s ease-in-out;
    display: block;
    background-color: var(--sidebar-bg);
  }
  
  .sidebar.mobile-open {
    left: 0;
  }
  
  .hamburger-btn {
    display: block;
    position: absolute; /* Non-sticky, scrolls with header */
    top: 10px; 
    right: 1rem;
    left: auto;
    background-color: var(--sidebar-bg);
    padding: 10px;
    height: 40px;
    width: 48px;
    border-radius: 4px;
    box-shadow: var(--shadow);
    z-index: 1001;
  }

  .hamburger-btn span {
    width: 28px;
    left: 10px;
  }

  .hamburger-btn span:nth-child(1) { top: 10px; }
  .hamburger-btn span:nth-child(2) { top: 18px; }
  .hamburger-btn span:nth-child(3) { top: 26px; }

  .hamburger-btn.active span:nth-child(1) { top: 18px; }
  .hamburger-btn.active span:nth-child(3) { top: 18px; }

  .logoImg {
    width: 240px;
    height: 50px;
  }
  
  .content-area {
    padding: 1rem;
    width: 100%;
    max-width: 100%;
  }
  
  .calc-card {
    padding: 1.5rem;
    width: 100%;
    margin-left: 0;
    margin-right: 0;
    max-width: 100%;
    text-align: center;
  }

  .input-with-label,
  .number-spinner {
    justify-content: center;
    margin-left: auto;
    margin-right: auto;
  }
}

/* Data Tables (Specific for large charts) */
.data-table {
  width: 100%;
  border-collapse: separate;
  border-spacing: 0;
  font-size: 0.875rem;
  background-color: var(--card-bg);
}

.data-table th,
.data-table td {
  padding: 0.75rem 1rem;
  border-bottom: 1px solid var(--border);
  border-right: 1px solid var(--border);
  text-align: right;
  color: var(--text);
}

.data-table th:last-child,
.data-table td:last-child {
  border-right: none;
}

.data-table thead th {
  background-color: var(--sidebar-bg);
  font-weight: 700;
  color: var(--text);
  position: sticky;
  top: 0;
  border-top: 1px solid var(--border);
}

.data-table tbody tr:nth-child(even) {
  background-color: rgba(255, 255, 255, 0.02);
}

.data-table tbody tr:hover {
  background-color: rgba(129, 140, 248, 0.1);
}

.data-table td:first-child {
  text-align: left;
  font-weight: 600;
  color: var(--primary);
  background-color: var(--sidebar-bg);
  position: sticky;
  left: 0;
  border-left: 1px solid var(--border);
}

/* Utilities */
.txtC { text-align: center; }
.mvm { margin-top: 1rem; margin-bottom: 1rem; }
.btn { cursor: pointer; display: inline-block; }
.btnDefault { 
  background-color: var(--primary); 
  color: white; 
  padding: 0.75rem 1.5rem; 
  border-radius: 0.5rem;
  font-weight: 600;
  transition: background-color 0.2s;
}
.btnDefault:hover { background-color: var(--primary-hover); }