/* OKLCH Color Strategy (Restrained: Slate neutrals + Indigo accent) */
:root {
  /* Light Theme */
  --bg-base: oklch(0.98 0.005 250);
  --bg-surface: oklch(0.99 0.003 250);
  --text-main: oklch(0.2 0.01 250);
  --text-muted: oklch(0.5 0.02 250);
  --border-color: oklch(0.9 0.01 250);
  --input-bg: oklch(1 0 0);
  
  --accent: oklch(0.55 0.15 260);
  --accent-hover: oklch(0.45 0.15 260);
  --accent-text: oklch(0.99 0.01 250);

  --error-bg: oklch(0.97 0.02 20);
  --error-text: oklch(0.4 0.12 20);
  --error-border: oklch(0.92 0.05 20);
  
  --ease-out-expo: cubic-bezier(0.19, 1, 0.22, 1);
}

[data-theme="dark"] {
  /* Dark Theme */
  --bg-base: oklch(0.15 0.01 250);
  --bg-surface: oklch(0.18 0.01 250);
  --text-main: oklch(0.95 0.01 250);
  --text-muted: oklch(0.7 0.01 250);
  --border-color: oklch(0.25 0.01 250);
  --input-bg: oklch(0.13 0.01 250);
  
  --accent: oklch(0.7 0.15 260);
  --accent-hover: oklch(0.75 0.15 260);
  --accent-text: oklch(0.15 0.01 250);

  --error-bg: oklch(0.25 0.05 20);
  --error-text: oklch(0.85 0.1 20);
  --error-border: oklch(0.3 0.05 20);
}

* {
  box-sizing: border-box;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background-color: var(--bg-base);
  color: var(--text-main);
  margin: 0;
  display: flex;
  justify-content: center;
  min-height: 100vh;
  padding: 4rem 1.5rem;
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

.container {
  width: 100%;
  max-width: 440px;
}

.header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: 2.5rem;
}

h1 {
  font-size: 1.75rem;
  font-weight: 600;
  margin: 0;
  letter-spacing: -0.02em;
  color: var(--text-main);
  max-width: 80%;
}

.theme-toggle {
  background: transparent;
  border: 1px solid var(--border-color);
  color: var(--text-muted);
  width: 40px;
  height: 40px;
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: color 0.3s var(--ease-out-expo), border-color 0.3s var(--ease-out-expo);
  flex-shrink: 0;
}

.theme-toggle:hover {
  color: var(--text-main);
  border-color: var(--text-muted);
}

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

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

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

input[type="text"] {
  width: 100%;
  padding: 0.875rem 1rem;
  font-size: 1rem;
  background-color: var(--input-bg);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  color: var(--text-main);
  transition: border-color 0.3s var(--ease-out-expo), box-shadow 0.3s var(--ease-out-expo);
}

input[type="text"]::placeholder {
  color: var(--text-muted);
  opacity: 0.6;
}

input[type="text"]:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px color-mix(in oklch, var(--accent) 20%, transparent);
}

.btn-primary {
  width: 100%;
  padding: 0.875rem 1.5rem;
  font-size: 1rem;
  font-weight: 500;
  background-color: var(--accent);
  color: var(--accent-text);
  border: none;
  border-radius: 8px;
  cursor: pointer;
  transition: background-color 0.3s var(--ease-out-expo);
}

.btn-primary:hover {
  background-color: var(--accent-hover);
}

/* Linear Loader */
.loader-container {
  display: none;
  margin-top: 2rem;
}

.loader-bar {
  width: 100%;
  height: 4px;
  background-color: var(--border-color);
  border-radius: 2px;
  overflow: hidden;
  position: relative;
  margin-bottom: 0.75rem;
}

.loader-progress {
  position: absolute;
  top: 0;
  left: 0;
  height: 100%;
  width: 30%;
  background-color: var(--accent);
  border-radius: 2px;
  animation: loading 1.5s infinite ease-in-out;
}

@keyframes loading {
  0% { left: -30%; width: 30%; }
  50% { width: 50%; }
  100% { left: 100%; width: 30%; }
}

#loaderText {
  font-size: 0.875rem;
  color: var(--text-muted);
  margin: 0;
}

/* Results Section */
.results-container {
  margin-top: 2.5rem;
}

.candidate-header {
  padding-bottom: 1.5rem;
  margin-bottom: 1.5rem;
  border-bottom: 1px solid var(--border-color);
}

.candidate-header .label {
  display: block;
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-muted);
  margin-bottom: 0.25rem;
}

.candidate-header .value {
  font-size: 1.125rem;
  font-weight: 500;
  color: var(--text-main);
}

.exam-result {
  margin-bottom: 3rem;
}

.exam-title {
  font-size: 1.125rem;
  font-weight: 500;
  color: var(--text-main);
  margin: 0 0 1rem 0;
}

.score-display {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  margin-bottom: 1.5rem;
}

.score-value {
  font-size: 4rem;
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.04em;
  color: var(--text-main);
}

.score-label {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-muted);
  margin-top: 0.5rem;
}

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

.stat {
  display: flex;
  flex-direction: column;
}

.stat-lbl {
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-bottom: 0.25rem;
}

.stat-val {
  font-size: 1rem;
  font-weight: 500;
  color: var(--text-main);
}

.error-msg {
  padding: 1rem 1.25rem;
  background-color: var(--error-bg);
  border: 1px solid var(--error-border);
  color: var(--error-text);
  border-radius: 8px;
  font-size: 0.875rem;
  line-height: 1.5;
}

.exam-error {
  padding: 1.5rem 0;
  border-bottom: 1px solid var(--border-color);
}

.exam-error-title {
  font-weight: 500;
  color: var(--error-text);
  margin-bottom: 0.25rem;
}

.exam-error-desc {
  font-size: 0.875rem;
  color: var(--text-muted);
}