:root {
  --bg: #0d1117;
  --text: #e6edf3;
  --accent: #00ff7f;
  --card: #161b22;
}

.light {
  --bg: #f5f5f5;
  --text: #111;
  --accent: #009966;
  --card: #ffffff;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: "Inter", -apple-system, BlinkMacSystemFont, sans-serif;
  background-color: var(--bg);
  color: var(--text);
  line-height: 1.6;
  transition: background 0.4s ease, color 0.4s ease;
  padding: 20px;
}

/* Header */
header {
  text-align: center;
  margin-bottom: 60px;
}

header h1 {
  font-size: 2.8rem;
  letter-spacing: 1px;
  margin-bottom: 8px;
}

.subtitle {
  font-size: 1rem;
  color: var(--accent);
  max-width: 700px;
  margin: 0 auto 20px auto;
  line-height: 1.5;
}

nav {
  display: flex;
  justify-content: center;
  gap: 18px;
  flex-wrap: wrap;
  align-items: center;
}

nav a {
  text-decoration: none;
  color: var(--text);
  font-weight: 500;
  transition: color 0.3s;
}

nav a:hover {
  color: var(--accent);
}

/* Theme Toggle */
#themeToggle {
  background: transparent;
  border: none;
  cursor: pointer;
  color: var(--accent);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 6px;
  border-radius: 50%;
  transition: all 0.3s ease;
}

#themeToggle:hover svg {
  transform: rotate(25deg);
  color: var(--text);
}

/* Sections */
section {
  max-width: 800px;
  margin: 50px auto;
  padding: 30px;
  background: var(--card);
  border-radius: 12px;
  box-shadow: 0 0 10px rgba(0,255,127,0.15);
  opacity: 0;
  transform: translateY(25px);
  transition: opacity 1s ease, transform 1s ease;
}

section.visible {
  opacity: 1;
  transform: translateY(0);
}

section h2 {
  color: var(--accent);
  margin-bottom: 18px;
  font-size: 1.4rem;
}

.feature-list {
  margin: 20px 0 30px;
  display: grid;
  gap: 10px;
  list-style: none;
}

.feature-list li {
  background: rgba(0, 255, 127, 0.05);
  padding: 10px 14px;
  border-radius: 10px;
  border: 1px solid rgba(0, 255, 127, 0.18);
  font-size: 0.95rem;
}

.super-calc-grid {
  display: grid;
  gap: 25px;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  margin-bottom: 30px;
}

.calc-device {
  background: radial-gradient(circle at 20% 20%, rgba(0, 255, 127, 0.2), rgba(0, 0, 0, 0.8));
  border-radius: 24px;
  padding: 24px;
  border: 1px solid rgba(0, 255, 127, 0.25);
  box-shadow: 0 15px 35px rgba(0, 255, 127, 0.15);
  display: flex;
  flex-direction: column;
  gap: 18px;
}

.calc-status {
  display: flex;
  justify-content: space-between;
  font-size: 0.85rem;
}

.badge {
  padding: 4px 10px;
  border-radius: 999px;
  border: 1px solid rgba(0, 255, 127, 0.6);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  font-size: 0.75rem;
}

.badge.ghost {
  border-color: rgba(255, 255, 255, 0.3);
  color: rgba(255, 255, 255, 0.6);
}

.calc-display {
  background: #010b0b;
  border-radius: 18px;
  padding: 18px;
  min-height: 120px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 10px;
  box-shadow: inset 0 0 25px rgba(0, 255, 127, 0.25);
}

.calc-equation {
  font-family: "Space Mono", "SFMono-Regular", monospace;
  font-size: 0.95rem;
  color: rgba(0, 255, 127, 0.85);
  text-shadow: 0 0 10px rgba(0, 255, 127, 0.5);
}

.calc-result {
  font-size: 2rem;
  font-weight: 600;
  color: #eafff5;
  text-shadow: 0 0 15px rgba(0, 255, 127, 0.9);
}

.calc-keypad {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 12px;
}

.calc-keypad button {
  background: rgba(255, 255, 255, 0.05);
  border: none;
  border-radius: 14px;
  padding: 14px 0;
  color: var(--text);
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
  box-shadow: 0 5px 10px rgba(0, 0, 0, 0.3);
}

.calc-keypad button:hover {
  transform: translateY(-2px);
  box-shadow: 0 12px 20px rgba(0, 0, 0, 0.35);
}

.calc-keypad button.accent {
  background: linear-gradient(135deg, #00ff7f, #0fb);
  color: #04130d;
}

.calc-keypad button.ghost {
  border: 1px solid rgba(255, 255, 255, 0.2);
}

.calc-companion {
  display: flex;
  flex-direction: column;
  gap: 18px;
}

.calc-notes,
.calc-history {
  background: rgba(0, 0, 0, 0.3);
  padding: 18px;
  border-radius: 16px;
  border: 1px solid rgba(0, 255, 127, 0.15);
  box-shadow: inset 0 0 12px rgba(0, 255, 127, 0.08);
}

.calc-notes h3,
.calc-history h3 {
  margin-bottom: 10px;
}

.calc-notes p {
  font-size: 0.9rem;
  margin-bottom: 6px;
}

.calc-history ul {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.calc-history li {
  background: rgba(255, 255, 255, 0.03);
  border-radius: 12px;
  padding: 10px 12px;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.calc-history .label {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: rgba(255, 255, 255, 0.6);
}

.calc-code {
  background: rgba(255, 255, 255, 0.02);
  border: 1px solid rgba(0, 255, 127, 0.2);
  border-radius: 14px;
  padding: 20px;
}

.calc-code pre {
  background: #050909;
  padding: 14px;
  border-radius: 12px;
  overflow-x: auto;
  font-size: 0.85rem;
}

.code-hint {
  font-size: 0.85rem;
  margin-top: 12px;
  color: rgba(255, 255, 255, 0.75);
}

body.light .calc-device {
  background: linear-gradient(180deg, #ffffff, #dfffee);
  box-shadow: 0 15px 25px rgba(0, 0, 0, 0.15);
}

body.light .calc-display {
  background: #f0fffb;
  box-shadow: inset 0 0 25px rgba(0, 255, 127, 0.15);
}

body.light .calc-keypad button {
  background: rgba(0, 0, 0, 0.05);
  color: #043124;
}

@media (max-width: 600px) {
  .calc-keypad {
    gap: 8px;
  }

  .calc-keypad button {
    padding: 12px 0;
  }
}

/* Projects */
.project h3 {
  color: var(--accent);
}

.project a {
  text-decoration: none;
  color: var(--accent);
  border: 1px solid var(--accent);
  padding: 6px 12px;
  border-radius: 6px;
  display: inline-block;
  margin-top: 8px;
  transition: background 0.3s, color 0.3s;
}

.project a:hover {
  background: var(--accent);
  color: #000;
}

/* Repo list */
.repo-list {
  display: grid;
  gap: 20px;
}

.repo {
  background: rgba(255,255,255,0.03);
  padding: 15px;
  border-radius: 8px;
  border: 1px solid rgba(0,255,127,0.1);
}

.repo a {
  color: var(--accent);
  font-weight: 600;
  text-decoration: none;
}

/* Contact */
.contact-links a {
  color: var(--accent);
  text-decoration: none;
  font-weight: 500;
  transition: color 0.3s ease;
}

.contact-links a:hover {
  color: var(--text);
}

/* Social Icons */
.social-icons {
  position: fixed;
  top: 18px;
  right: 25px;
  display: flex;
  gap: 18px;
  z-index: 100;
}

.social-icons svg {
  color: var(--accent);
  opacity: 0.8;
  transition: all 0.3s ease;
}

.social-icons svg:hover {
  opacity: 1;
  transform: scale(1.1);
  color: var(--text);
}

/* Footer */
footer {
  text-align: center;
  margin-top: 60px;
  font-size: 0.9rem;
  color: #777;
}