/* CSS Variables for Dark/Light Mode */
:root {
  /* Dark mode colors (default) */
  --bg-color: #0f172a;
  --card-bg: rgba(30, 41, 59, 0.7);
  --card-bg-hover: rgba(30, 41, 59, 0.85);
  --card-border: rgba(148, 163, 184, 0.1);
  --card-border-hover: rgba(96, 165, 250, 0.3);
  --card-shadow: rgba(0, 0, 0, 0.4);
  --text-primary: #cbd5e1;
  --text-secondary: #e2e8f0;
  --header-text: white;
  --heading-gradient-start: #60a5fa;
  --heading-gradient-mid: #a78bfa;
  --heading-gradient-end: #f472b6;
  --accent-color: #60a5fa;
  --input-bg: #1e293b;
  --input-border: #334155;
  --input-border-hover: #475569;
  --input-text: #e2e8f0;
  --paragraph-bg: rgba(15, 23, 42, 0.4);
  --table-bg: rgba(15, 23, 42, 0.4);
  --table-border: rgba(148, 163, 184, 0.08);
  --table-header-bg: #a78bfa;
  --table-row-even: rgba(30, 41, 59, 0.3);
  --table-row-hover: rgba(96, 165, 250, 0.1);
}

[data-theme="light"] {
  /* Light mode colors */
  --bg-color: #e2e8f0;
  --card-bg: rgba(255, 255, 255, 0.9);
  --card-bg-hover: rgba(255, 255, 255, 1);
  --card-border: rgba(148, 163, 184, 0.2);
  --card-border-hover: rgba(37, 99, 235, 0.3);
  --card-shadow: rgba(0, 0, 0, 0.1);
  --text-primary: #334155;
  --text-secondary: #1e293b;
  --header-text: #1e293b;
  --heading-gradient-start: #2563eb;
  --heading-gradient-mid: #7c3aed;
  --heading-gradient-end: #ec4899;
  --accent-color: #2563eb;
  --input-bg: #ffffff;
  --input-border: #cbd5e1;
  --input-border-hover: #94a3b8;
  --input-text: #1e293b;
  --paragraph-bg: rgba(241, 245, 249, 0.8);
  --table-bg: rgba(248, 250, 252, 0.8);
  --table-border: rgba(203, 213, 225, 0.3);
  --table-header-bg: #7c3aed;
  --table-row-even: rgba(241, 245, 249, 0.5);
  --table-row-hover: rgba(224, 242, 254, 0.5);
}

/* Theme Toggle Button */
#theme-toggle {
  position: relative;
  margin: 20px auto 0 auto;
  display: flex;
  background: var(--card-bg);
  border: 2px solid var(--input-border);
  border-radius: 50px;
  padding: 10px 16px;
  cursor: pointer;
  font-size: 1.2rem;
  transition: all 0.3s ease;
  align-items: center;
  gap: 8px;
  box-shadow: 0 4px 12px var(--card-shadow);
  width: fit-content;
}

#theme-toggle:hover {
  transform: scale(1.05);
  border-color: var(--accent-color);
}

#theme-toggle .sun-icon {
  display: none;
}

#theme-toggle .moon-icon {
  display: inline;
}

[data-theme="light"] #theme-toggle .sun-icon {
  display: inline;
}

[data-theme="light"] #theme-toggle .moon-icon {
  display: none;
}

/* Reset and Base Styles */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Inter', 'Segoe UI', sans-serif;
  background: var(--bg-color);
  min-height: 100vh;
  padding: 40px 20px;
  color: var(--text-primary);
  width: 100vw;
  transition: background 0.3s ease;
}

/* Page Header */
.page-header {
  max-width: 1400px;
  margin: 0 auto 40px auto;
  text-align: center;
  color: var(--header-text);
  position: relative;
}

.page-header h1 {
  font-size: clamp(2rem, 5vw, 3.5rem);
  font-weight: 800;
  margin-bottom: 16px;
  background: linear-gradient(135deg, var(--heading-gradient-start) 0%, var(--heading-gradient-mid) 50%, var(--heading-gradient-end) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  border: none;
  letter-spacing: -1px;
}

.page-header .subtitle {
  font-size: clamp(1rem, 2.5vw, 1.25rem);
  font-weight: 400;
  color: var(--text-primary);
  margin: 0;
  padding: 0;
  background: none;
  line-height: 1.6;
  border-style: none;
}

/* Main wrapper for masonry grid layout */
.container {
  column-count: 3;
  column-gap: 24px;
  display: block;
  margin: 0 auto;
}

select {
  padding: 14px 16px;
  border: 1.5px solid var(--input-border);
  border-radius: 12px;
  font-size: 0.95rem;
  background: var(--input-bg);
  color: var(--input-text);
  cursor: pointer;
  transition: all 0.2s ease;
  font-weight: 500;
}

select:focus {
  outline: none;
  border-color: var(--accent-color);
  background: var(--input-bg);
  box-shadow: 0 0 0 3px rgba(96, 165, 250, 0.1);
}

select:hover {
  border-color: var(--input-border-hover);
  background: var(--input-bg);
}

/* Container */
.income_tax, .pension, .national_insurance, .student_finance, .summary {
  background: var(--card-bg);
  backdrop-filter: blur(20px);
  border: 1px solid var(--card-border);
  border-radius: 20px;
  padding: 15px;
  margin-bottom: 24px;
  break-inside: avoid;
  transition: all 0.3s ease;
}

/* Headings */
h2 {
  background: linear-gradient(135deg, var(--heading-gradient-start) 0%, var(--heading-gradient-mid) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  font-size: 1.4rem;
  border: none;
  padding-bottom: 12px;
  font-weight: 700;
  letter-spacing: -0.5px;
  position: relative;
  margin-bottom: 10px;
}

h2::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 60px;
  height: 3px;
  background: linear-gradient(90deg, var(--heading-gradient-start) 0%, var(--heading-gradient-mid) 100%);
  border-radius: 2px;
}

/* Red text notes for various sections */
.section_notice {
  background: none;
  padding: 0;
  margin: 10px 0 10px 0;
  color: #D22B2B;
  font-size: .8rem;
  border: none;
  position: relative;
}

/* Student Finance Checkboxes */
/* Layout (keeps your existing structure) */
.plan-checkboxes {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
}

.plan-checkboxes label {
  margin: 5px;
}

/* Label */
.plan-checkboxes .checkbox-label {
  position: relative;
  display: flex;
  align-items: center;
  padding-left: 28px;
  cursor: pointer;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-primary, #111);
  user-select: none;
}

/* Hide native checkbox */
.checkbox-label input[type="checkbox"] {
  position: absolute;
  opacity: 0;
  pointer-events: none;
}

/* Custom box */
.checkbox-label::before {
  content: "";
  position: absolute;
  left: 0;
  width: 18px;
  height: 18px;
  border: 1px solid #c8ccd4;
  border-radius: 4px;
  background: #fff;
  transition: background 0.1s ease, border-color 0.1s ease;
}

/* Checkmark */
.checkbox-label::after {
  content: "";
  position: absolute;
  left: 6px;
  top: 3px;
  width: 5px;
  height: 10px;
  opacity: 0;
  transform: rotate(45deg) scale(0);
  border-right: 2px solid #fff;
  border-bottom: 2px solid #fff;
  transition: all 0.3s ease;
  transition-delay: 0.15s;
}

/* Checked state */
.checkbox-label:has(input[type="checkbox"]:checked)::before {
  background: var(--table-header-bg);
  border-color: transparent;
  animation: jelly-42 0.6s ease;
}

.checkbox-label:has(input[type="checkbox"]:checked)::after {
  opacity: 1;
  transform: rotate(45deg) scale(1);
}

/* Hover */
.checkbox-label:hover::before {
  border-color: var(--table-header-bg);
}

/* Focus (keyboard accessibility) */
.checkbox-label:has(input[type="checkbox"]:focus-visible)::before {
  outline: 2px solid var(--table-header-bg);
  outline-offset: 2px;
}

/* Jelly animation (unchanged behaviour) */
@keyframes jelly-42 {
  0% { transform: scale(1); }
  30% { transform: scale(1.25, 0.75); }
  40% { transform: scale(0.75, 1.25); }
  50% { transform: scale(1.15, 0.85); }
  65% { transform: scale(0.95, 1.05); }
  75% { transform: scale(1.05, 0.95); }
  100% { transform: scale(1); }
}


/* Labels and Inputs */
label {
  display: block;
  font-weight: 600;
  color: var(--text-primary);
  font-size: 0.9rem;
  letter-spacing: 0.3px;
  margin: 15px 0 15px 0;
}

input, select {
  width: 50%;
  padding: 5px;
  border: 1.5px solid var(--input-border);
  border-radius: 12px;
  font-size: 0.95rem;
  background: var(--input-bg);
  color: var(--input-text);
  transition: all 0.2s ease;
  font-weight: 500;
}

input:focus {
  outline: none;
  border-color: var(--accent-color);
  background: var(--input-bg);
  box-shadow: 0 0 0 3px rgba(96, 165, 250, 0.1);
}

input:hover {
  border-color: var(--input-border-hover);
  background: var(--input-bg);
}

/* Paragraphs with spans */
p {
  margin-bottom: 12px;
  padding: 16px 18px;
  background: var(--paragraph-bg);
  border-radius: 12px;
  font-size: 0.85rem;
  border: 1px solid var(--card-border);
  color: var(--text-primary);
  font-weight: 500;
}

p span {
  font-weight: 700;
  background: linear-gradient(135deg, var(--heading-gradient-start) 0%, var(--heading-gradient-mid) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  float: right;
  font-size: 0.9rem;
}

#net_take_home_figure,
#net_monthly_take_home_figure {
  background: linear-gradient(135deg, #33a75c 0%, #6fdc9f 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

#effective_tax_rate {
  background: linear-gradient(135deg, #d32f2f 0%, #ff5252 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

/* Table Styles */
table {
  border-collapse: collapse;
  width: 100%;
  margin: 25px 0;
  background: var(--table-bg);
  border-radius: 16px;
  overflow: hidden;
  border: 1px solid var(--card-border);
  table-layout: fixed;
}

th {
  background-color: var(--table-header-bg);
  color: white;
  font-weight: 700;
  padding: 14px 8px;
  text-align: center;
  text-transform: uppercase;
  font-size: clamp(0.7rem, 1vw, 0.7rem);
  word-wrap: break-word;
}

td {
  border: 1px solid var(--table-border);
  text-align: center;
  padding: 12px 8px;
  font-size: clamp(0.7rem, 1vw, 0.7rem);
  word-wrap: break-word;
  color: var(--text-primary);
  font-weight: 500;
}

tr:nth-child(even) {
  background-color: var(--table-row-even);
}

tr:hover {
  background: var(--table-row-hover);
  transition: background 0.2s ease;
}

.error{
  border-color: #f87171 !important;
  background-color: rgba(239, 68, 68, 0.1);
}

@media (max-width: 1350px) {
  .container {
    column-count: 2;
  }
  td {
    font-size: clamp(0.65rem, 1.6vw, 0.8rem);
  }
}

@media (max-width: 1024px) {
  body {
    padding: 30px 15px;
  }
  .container {
    column-count: 1;
  }
  .page-header {
    margin-bottom: 40px;
  }
  #theme-toggle {
    padding: 8px 12px;
    font-size: 1rem;
  }
  input, select {
    width: 100%;
    margin: 10px 0 5px 0;
  }
  th {
    padding: 12px 6px;
  }
  td {
    padding: 10px 6px;
  }
}

@media (max-width: 400px) {
  body {
    padding: 20px 10px;
  }
  #theme-toggle {
    padding: 6px 10px;
    font-size: 0.9rem;
  }
  th {
    padding: 10px 4px;
  }
  td {
    padding: 8px 4px;
  }
}