/* ============================================
   CalcTools - Main Stylesheet
   Theme: Black & White Modern
   ============================================ */

/* CSS Variables */
:root {
  --black: #000000;
  --white: #ffffff;
  --gray-100: #f5f5f5;
  --gray-200: #e5e5e5;
  --gray-300: #d4d4d4;
  --gray-400: #a3a3a3;
  --gray-500: #737373;
  --gray-600: #525252;
  --gray-700: #404040;
  --gray-800: #262626;
  --gray-900: #171717;
  --accent: #111111;
  --transition: all 0.3s ease;
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.12), 0 1px 2px rgba(0,0,0,0.24);
  --shadow-md: 0 4px 6px rgba(0,0,0,0.07), 0 2px 4px rgba(0,0,0,0.05);
  --shadow-lg: 0 10px 30px rgba(0,0,0,0.1);
  --shadow-xl: 0 20px 60px rgba(0,0,0,0.15);
  --border-radius: 12px;
  --border-radius-lg: 20px;
  --font-main: 'Inter', sans-serif;
}

/* Reset & Base */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: var(--font-main);
  background-color: var(--white);
  color: var(--gray-800);
  line-height: 1.6;
  overflow-x: hidden;
}

a {
  text-decoration: none;
  color: inherit;
  transition: var(--transition);
}

ul {
  list-style: none;
}

img {
  max-width: 100%;
  height: auto;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
  font-weight: 700;
  line-height: 1.2;
  color: var(--black);
}

h1 { font-size: clamp(2rem, 5vw, 3.5rem); }
h2 { font-size: clamp(1.5rem, 3vw, 2.5rem); }
h3 { font-size: clamp(1.2rem, 2vw, 1.8rem); }
h4 { font-size: 1.2rem; }
h5 { font-size: 1rem; }

p { color: var(--gray-600); line-height: 1.8; }

/* ============================================
   NAVBAR
   ============================================ */
.navbar {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: rgba(0, 0, 0, 0.97);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid rgba(255,255,255,0.08);
  padding: 0 2rem;
}

.nav-container {
  max-width: 1280px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 70px;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--white);
  letter-spacing: -0.5px;
}

.nav-logo span {
  color: var(--gray-300);
  font-weight: 400;
  font-size: 0.9rem;
}

.nav-logo-icon {
  width: 36px;
  height: 36px;
  background: var(--white);
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--black);
  font-size: 1.1rem;
  font-weight: 900;
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.nav-item {
  position: relative;
}

.nav-link {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 0.6rem 1rem;
  color: rgba(255,255,255,0.85);
  font-size: 0.9rem;
  font-weight: 500;
  border-radius: 8px;
  transition: var(--transition);
  cursor: pointer;
  white-space: nowrap;
}

.nav-link:hover {
  color: var(--white);
  background: rgba(255,255,255,0.1);
}

.nav-link.active {
  color: var(--white);
  background: rgba(255,255,255,0.1);
}

.nav-link svg {
  transition: transform 0.3s ease;
}

.nav-item:hover .nav-link svg {
  transform: rotate(180deg);
}

/* Dropdown */
.dropdown {
  position: absolute;
  top: calc(100% + 8px);
  left: 50%;
  transform: translateX(-50%) translateY(-10px);
  background: var(--white);
  border: 1px solid var(--gray-200);
  border-radius: var(--border-radius);
  box-shadow: var(--shadow-xl);
  min-width: 260px;
  opacity: 0;
  visibility: hidden;
  transition: all 0.3s ease;
  padding: 0.5rem;
}

.nav-item:hover .dropdown {
  opacity: 1;
  visibility: visible;
  transform: translateX(-50%) translateY(0);
}

.dropdown-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2px;
}

.dropdown-item {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 0.6rem 0.8rem;
  color: var(--gray-700);
  font-size: 0.85rem;
  font-weight: 500;
  border-radius: 8px;
  transition: var(--transition);
}

.dropdown-item:hover {
  background: var(--gray-100);
  color: var(--black);
}

.dropdown-item-icon {
  width: 28px;
  height: 28px;
  background: var(--gray-100);
  border-radius: 6px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.85rem;
  flex-shrink: 0;
}

/* Mobile Nav Toggle */
.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  padding: 0.5rem;
  background: none;
  border: none;
  outline: none;
}

.nav-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--white);
  border-radius: 2px;
  transition: var(--transition);
}

.nav-toggle.open span:nth-child(1) {
  transform: rotate(45deg) translate(5px, 5px);
}

.nav-toggle.open span:nth-child(2) {
  opacity: 0;
}

.nav-toggle.open span:nth-child(3) {
  transform: rotate(-45deg) translate(5px, -5px);
}

/* ============================================
   HERO SECTION
   ============================================ */
.hero {
  position: relative;
  background: var(--black);
  min-height: 92vh;
  display: flex;
  align-items: center;
  overflow: hidden;
}

.hero-bg {
  position: absolute;
  inset: 0;
  overflow: hidden;
  pointer-events: none;
}

/* Gradient mesh */
.hero-bg::before {
  content: '';
  position: absolute;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  background: radial-gradient(ellipse at 30% 50%, rgba(255,255,255,0.04) 0%, transparent 60%),
              radial-gradient(ellipse at 70% 20%, rgba(255,255,255,0.03) 0%, transparent 50%);
}

/* Particle canvas area */
.particles-canvas {
  position: absolute;
  inset: 0;
}

.particle {
  position: absolute;
  pointer-events: none;
  animation: float-particle linear infinite;
  opacity: 0;
}

.particle svg {
  fill: none;
  stroke: rgba(255,255,255,0.25);
  stroke-width: 1.5;
}

@keyframes float-particle {
  0% {
    opacity: 0;
    transform: translateY(0) rotate(0deg);
  }
  10% { opacity: 1; }
  90% { opacity: 0.6; }
  100% {
    opacity: 0;
    transform: translateY(-100vh) rotate(720deg);
  }
}

.hero-content {
  position: relative;
  z-index: 2;
  max-width: 1280px;
  margin: 0 auto;
  padding: 4rem 2rem;
  text-align: center;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: rgba(255,255,255,0.08);
  border: 1px solid rgba(255,255,255,0.15);
  color: rgba(255,255,255,0.8);
  padding: 0.4rem 1rem;
  border-radius: 50px;
  font-size: 0.82rem;
  font-weight: 500;
  letter-spacing: 0.5px;
  margin-bottom: 2rem;
  animation: fadeInDown 0.6s ease forwards;
}

.hero-badge-dot {
  width: 6px;
  height: 6px;
  background: #4ade80;
  border-radius: 50%;
  animation: pulse-green 2s infinite;
}

@keyframes pulse-green {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.5; transform: scale(1.5); }
}

.hero-title {
  font-size: clamp(3rem, 8vw, 6rem);
  font-weight: 900;
  color: var(--white);
  letter-spacing: -2px;
  margin-bottom: 1.2rem;
  animation: fadeInUp 0.7s ease forwards;
  animation-delay: 0.1s;
  opacity: 0;
}

.hero-title .highlight {
  background: linear-gradient(135deg, #ffffff 0%, #a3a3a3 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-subtitle {
  font-size: clamp(1rem, 2.5vw, 1.3rem);
  color: rgba(255,255,255,0.6);
  max-width: 600px;
  margin: 0 auto 2.5rem;
  animation: fadeInUp 0.7s ease forwards;
  animation-delay: 0.2s;
  opacity: 0;
}

.hero-actions {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
  animation: fadeInUp 0.7s ease forwards;
  animation-delay: 0.3s;
  opacity: 0;
}

.hero-stats {
  display: flex;
  gap: 3rem;
  justify-content: center;
  margin-top: 5rem;
  animation: fadeInUp 0.7s ease forwards;
  animation-delay: 0.5s;
  opacity: 0;
}

.hero-stat {
  text-align: center;
}

.hero-stat-number {
  font-size: 2rem;
  font-weight: 800;
  color: var(--white);
}

.hero-stat-label {
  font-size: 0.8rem;
  color: rgba(255,255,255,0.5);
  text-transform: uppercase;
  letter-spacing: 1px;
}

/* ============================================
   BUTTONS
   ============================================ */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 0.85rem 2rem;
  border-radius: var(--border-radius);
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  border: none;
  transition: var(--transition);
  letter-spacing: 0.3px;
  text-decoration: none;
}

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

.btn-primary:hover {
  background: var(--gray-100);
  transform: translateY(-2px);
  box-shadow: 0 8px 25px rgba(255,255,255,0.2);
  color: var(--black);
}

.btn-secondary {
  background: transparent;
  color: var(--white);
  border: 1px solid rgba(255,255,255,0.3);
}

.btn-secondary:hover {
  background: rgba(255,255,255,0.1);
  border-color: rgba(255,255,255,0.6);
  transform: translateY(-2px);
  color: var(--white);
}

.btn-dark {
  background: var(--black);
  color: var(--white);
}

.btn-dark:hover {
  background: var(--gray-800);
  transform: translateY(-2px);
  box-shadow: 0 8px 25px rgba(0,0,0,0.2);
  color: var(--white);
}

.btn-outline {
  background: transparent;
  color: var(--black);
  border: 2px solid var(--black);
}

.btn-outline:hover {
  background: var(--black);
  color: var(--white);
  transform: translateY(-2px);
}

.btn-lg {
  padding: 1rem 2.5rem;
  font-size: 1rem;
}

.btn-sm {
  padding: 0.5rem 1.2rem;
  font-size: 0.82rem;
}

/* ============================================
   SECTIONS
   ============================================ */
section {
  padding: 5rem 2rem;
}

.container {
  max-width: 1280px;
  margin: 0 auto;
}

.section-header {
  text-align: center;
  margin-bottom: 3.5rem;
}

.section-tag {
  display: inline-block;
  background: var(--gray-100);
  color: var(--gray-600);
  padding: 0.3rem 0.9rem;
  border-radius: 50px;
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 1px;
  text-transform: uppercase;
  margin-bottom: 1rem;
}

.section-title {
  margin-bottom: 1rem;
}

.section-desc {
  max-width: 600px;
  margin: 0 auto;
  font-size: 1rem;
}

/* ============================================
   TOOL CARDS
   ============================================ */
.tools-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 1.5rem;
}

.tool-card {
  background: var(--white);
  border: 1px solid var(--gray-200);
  border-radius: var(--border-radius-lg);
  padding: 1.8rem;
  transition: var(--transition);
  position: relative;
  overflow: hidden;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.tool-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: var(--black);
  transform: scaleX(0);
  transition: transform 0.3s ease;
}

.tool-card:hover::before {
  transform: scaleX(1);
}

.tool-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-xl);
  border-color: var(--gray-300);
}

.tool-card-icon {
  width: 52px;
  height: 52px;
  background: var(--gray-100);
  border-radius: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  transition: var(--transition);
}

.tool-card:hover .tool-card-icon {
  background: var(--black);
}

.tool-card-title {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--black);
}

.tool-card-desc {
  font-size: 0.85rem;
  color: var(--gray-500);
  line-height: 1.6;
  flex: 1;
}

.tool-card-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--black);
  border: 1.5px solid var(--gray-300);
  padding: 0.5rem 1rem;
  border-radius: 8px;
  transition: var(--transition);
  width: fit-content;
}

.tool-card-link:hover {
  background: var(--black);
  color: var(--white);
  border-color: var(--black);
}

/* ============================================
   FEATURES SECTION
   ============================================ */
.features-section {
  background: var(--black);
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 2rem;
}

.feature-card {
  text-align: center;
  padding: 2.5rem 1.5rem;
  border: 1px solid rgba(255,255,255,0.08);
  border-radius: var(--border-radius-lg);
  transition: var(--transition);
}

.feature-card:hover {
  border-color: rgba(255,255,255,0.2);
  background: rgba(255,255,255,0.03);
  transform: translateY(-4px);
}

.feature-icon {
  width: 60px;
  height: 60px;
  background: rgba(255,255,255,0.08);
  border-radius: 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.6rem;
  margin: 0 auto 1.5rem;
  transition: var(--transition);
}

.feature-card:hover .feature-icon {
  background: var(--white);
}

.feature-title {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--white);
  margin-bottom: 0.8rem;
}

.feature-desc {
  font-size: 0.88rem;
  color: rgba(255,255,255,0.5);
  line-height: 1.7;
}

/* ============================================
   SEO CONTENT SECTION
   ============================================ */
.seo-section {
  background: var(--gray-100);
}

.seo-content {
  max-width: 900px;
  margin: 0 auto;
  background: var(--white);
  border-radius: var(--border-radius-lg);
  padding: 3rem;
  box-shadow: var(--shadow-md);
}

.seo-content h2 {
  font-size: 1.6rem;
  margin-bottom: 1.2rem;
  margin-top: 2rem;
  color: var(--black);
}

.seo-content h2:first-child {
  margin-top: 0;
}

.seo-content p {
  margin-bottom: 1.2rem;
  font-size: 0.95rem;
  line-height: 1.85;
}

.seo-content ul {
  list-style: disc;
  padding-left: 1.5rem;
  margin-bottom: 1.2rem;
}

.seo-content ul li {
  color: var(--gray-600);
  margin-bottom: 0.5rem;
  font-size: 0.95rem;
  line-height: 1.7;
}

/* ============================================
   CTA SECTION
   ============================================ */
.cta-section {
  background: var(--black);
  text-align: center;
  padding: 6rem 2rem;
}

.cta-title {
  color: var(--white);
  margin-bottom: 1rem;
}

.cta-subtitle {
  color: rgba(255,255,255,0.6);
  max-width: 500px;
  margin: 0 auto 2.5rem;
}

/* ============================================
   FOOTER
   ============================================ */
.footer {
  background: var(--gray-900);
  color: var(--gray-400);
  padding: 4rem 2rem 0;
}

.footer-container {
  max-width: 1280px;
  margin: 0 auto;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 3rem;
  padding-bottom: 3rem;
  border-bottom: 1px solid rgba(255,255,255,0.08);
}

.footer-brand .nav-logo {
  margin-bottom: 1.2rem;
}

.footer-brand p {
  font-size: 0.88rem;
  color: var(--gray-500);
  line-height: 1.7;
  margin-bottom: 1.5rem;
  max-width: 260px;
}

.social-links {
  display: flex;
  gap: 0.8rem;
}

.social-link {
  width: 36px;
  height: 36px;
  background: rgba(255,255,255,0.06);
  border: 1px solid rgba(255,255,255,0.1);
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--gray-400);
  font-size: 0.9rem;
  transition: var(--transition);
}

.social-link:hover {
  background: var(--white);
  color: var(--black);
  border-color: var(--white);
}

.footer-col h4 {
  font-size: 0.9rem;
  font-weight: 700;
  color: var(--white);
  text-transform: uppercase;
  letter-spacing: 1px;
  margin-bottom: 1.5rem;
}

.footer-links {
  display: flex;
  flex-direction: column;
  gap: 0.7rem;
}

.footer-links a {
  font-size: 0.88rem;
  color: var(--gray-500);
  transition: var(--transition);
  display: flex;
  align-items: center;
  gap: 6px;
}

.footer-links a:hover {
  color: var(--white);
  padding-left: 4px;
}

.footer-bottom {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1.5rem 0;
  gap: 1rem;
  flex-wrap: wrap;
}

.footer-bottom p {
  font-size: 0.82rem;
  color: var(--gray-600);
}

.footer-bottom-links {
  display: flex;
  gap: 1.5rem;
}

.footer-bottom-links a {
  font-size: 0.82rem;
  color: var(--gray-600);
  transition: var(--transition);
}

.footer-bottom-links a:hover {
  color: var(--white);
}

/* ============================================
   CALCULATOR PAGES
   ============================================ */
.page-hero {
  background: var(--black);
  padding: 4rem 2rem;
  text-align: center;
}

.page-hero-title {
  color: var(--white);
  font-size: clamp(1.8rem, 4vw, 3rem);
  margin-bottom: 0.8rem;
}

.page-hero-desc {
  color: rgba(255,255,255,0.6);
  max-width: 600px;
  margin: 0 auto;
  font-size: 1rem;
}

.breadcrumb {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  justify-content: center;
  margin-bottom: 1.5rem;
  font-size: 0.82rem;
}

.breadcrumb a {
  color: rgba(255,255,255,0.5);
  transition: var(--transition);
}

.breadcrumb a:hover {
  color: var(--white);
}

.breadcrumb-sep {
  color: rgba(255,255,255,0.25);
}

.breadcrumb-current {
  color: rgba(255,255,255,0.8);
}

/* Calculator Widget */
.calc-section {
  padding: 4rem 2rem;
  background: var(--gray-100);
}

.calc-widget {
  background: var(--white);
  border-radius: var(--border-radius-lg);
  box-shadow: var(--shadow-xl);
  max-width: 700px;
  margin: 0 auto;
  overflow: hidden;
}

.calc-header {
  background: var(--black);
  padding: 1.8rem 2rem;
  display: flex;
  align-items: center;
  gap: 1rem;
}

.calc-header-icon {
  width: 44px;
  height: 44px;
  background: rgba(255,255,255,0.1);
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.3rem;
}

.calc-header h2 {
  color: var(--white);
  font-size: 1.2rem;
  font-weight: 700;
}

.calc-header p {
  color: rgba(255,255,255,0.5);
  font-size: 0.82rem;
}

.calc-body {
  padding: 2rem;
}

.form-group {
  margin-bottom: 1.3rem;
}

.form-label {
  display: block;
  font-size: 0.88rem;
  font-weight: 600;
  color: var(--gray-700);
  margin-bottom: 0.5rem;
}

.form-input {
  width: 100%;
  padding: 0.8rem 1rem;
  border: 2px solid var(--gray-200);
  border-radius: 10px;
  font-size: 1rem;
  font-family: var(--font-main);
  color: var(--gray-800);
  background: var(--white);
  transition: var(--transition);
  outline: none;
}

.form-input:focus {
  border-color: var(--black);
  box-shadow: 0 0 0 3px rgba(0,0,0,0.08);
}

.form-input::placeholder {
  color: var(--gray-400);
}

.form-select {
  width: 100%;
  padding: 0.8rem 1rem;
  border: 2px solid var(--gray-200);
  border-radius: 10px;
  font-size: 1rem;
  font-family: var(--font-main);
  color: var(--gray-800);
  background: var(--white);
  transition: var(--transition);
  outline: none;
  cursor: pointer;
  appearance: none;
  -webkit-appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' viewBox='0 0 24 24' fill='none' stroke='%23737373' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='M6 9l6 6 6-6'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 1rem center;
  padding-right: 2.5rem;
}

.form-select:focus {
  border-color: var(--black);
  box-shadow: 0 0 0 3px rgba(0,0,0,0.08);
}

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}

.calc-btn {
  width: 100%;
  padding: 1rem;
  background: var(--black);
  color: var(--white);
  border: none;
  border-radius: 10px;
  font-size: 1rem;
  font-weight: 700;
  cursor: pointer;
  transition: var(--transition);
  font-family: var(--font-main);
  letter-spacing: 0.3px;
  margin-top: 0.5rem;
}

.calc-btn:hover {
  background: var(--gray-800);
  transform: translateY(-2px);
  box-shadow: 0 8px 20px rgba(0,0,0,0.15);
}

.calc-btn:active {
  transform: translateY(0);
}

.calc-btn-reset {
  width: 100%;
  padding: 0.8rem;
  background: transparent;
  color: var(--gray-500);
  border: 2px solid var(--gray-200);
  border-radius: 10px;
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
  font-family: var(--font-main);
  margin-top: 0.8rem;
}

.calc-btn-reset:hover {
  border-color: var(--gray-400);
  color: var(--gray-700);
}

/* Result Box */
.result-box {
  display: none;
  margin-top: 1.5rem;
  padding: 1.5rem;
  background: var(--gray-100);
  border-radius: 12px;
  border-left: 4px solid var(--black);
  animation: slideUp 0.4s ease;
}

.result-box.show {
  display: block;
}

@keyframes slideUp {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: translateY(0); }
}

.result-title {
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--gray-500);
  text-transform: uppercase;
  letter-spacing: 1px;
  margin-bottom: 0.8rem;
}

.result-value {
  font-size: 2rem;
  font-weight: 800;
  color: var(--black);
  line-height: 1;
  margin-bottom: 0.3rem;
}

.result-sub {
  font-size: 0.88rem;
  color: var(--gray-500);
}

.result-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 1rem;
}

.result-item {
  background: var(--white);
  border-radius: 10px;
  padding: 1rem;
  text-align: center;
  border: 1px solid var(--gray-200);
}

.result-item-label {
  font-size: 0.75rem;
  color: var(--gray-500);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  margin-bottom: 0.4rem;
}

.result-item-value {
  font-size: 1.4rem;
  font-weight: 800;
  color: var(--black);
}

.result-item-unit {
  font-size: 0.78rem;
  color: var(--gray-400);
}

.error-msg {
  display: none;
  color: #dc2626;
  font-size: 0.82rem;
  margin-top: 0.4rem;
}

.error-msg.show { display: block; }

/* ============================================
   TOOL DESCRIPTION & FAQ
   ============================================ */
.tool-content-section {
  padding: 4rem 2rem;
}

.tool-content {
  max-width: 900px;
  margin: 0 auto;
}

.tool-desc {
  background: var(--white);
  border-radius: var(--border-radius-lg);
  padding: 2.5rem;
  margin-bottom: 2rem;
  box-shadow: var(--shadow-md);
}

.tool-desc h2 {
  font-size: 1.5rem;
  margin-bottom: 1.2rem;
  color: var(--black);
}

.tool-desc h3 {
  font-size: 1.15rem;
  margin: 1.8rem 0 0.8rem;
  color: var(--black);
}

.tool-desc p {
  font-size: 0.95rem;
  line-height: 1.85;
  color: var(--gray-600);
  margin-bottom: 1rem;
}

.tool-desc ul {
  list-style: none;
  margin-bottom: 1.2rem;
}

.tool-desc ul li {
  font-size: 0.95rem;
  color: var(--gray-600);
  padding: 0.3rem 0 0.3rem 1.5rem;
  position: relative;
}

.tool-desc ul li::before {
  content: '→';
  position: absolute;
  left: 0;
  color: var(--gray-400);
}

/* FAQ */
.faq-section {
  background: var(--white);
  border-radius: var(--border-radius-lg);
  padding: 2.5rem;
  box-shadow: var(--shadow-md);
}

.faq-title {
  font-size: 1.5rem;
  margin-bottom: 1.5rem;
  color: var(--black);
}

.faq-item {
  border-bottom: 1px solid var(--gray-200);
  overflow: hidden;
}

.faq-item:last-child {
  border-bottom: none;
}

.faq-question {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1.2rem 0;
  cursor: pointer;
  font-weight: 600;
  font-size: 0.95rem;
  color: var(--black);
  transition: var(--transition);
  gap: 1rem;
  user-select: none;
}

.faq-question:hover {
  color: var(--gray-700);
}

.faq-icon {
  width: 24px;
  height: 24px;
  flex-shrink: 0;
  background: var(--gray-100);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1rem;
  font-weight: 700;
  transition: var(--transition);
  color: var(--black);
}

.faq-item.open .faq-icon {
  background: var(--black);
  color: var(--white);
  transform: rotate(45deg);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.35s ease;
}

.faq-answer-inner {
  padding: 0 0 1.2rem;
  font-size: 0.92rem;
  color: var(--gray-600);
  line-height: 1.8;
}

/* ============================================
   ABOUT / CONTACT / STATIC PAGES
   ============================================ */
.static-section {
  padding: 4rem 2rem;
}

.static-content {
  max-width: 800px;
  margin: 0 auto;
  background: var(--white);
  border-radius: var(--border-radius-lg);
  padding: 3rem;
  box-shadow: var(--shadow-md);
}

.static-content h2 {
  font-size: 1.4rem;
  margin: 2rem 0 1rem;
  color: var(--black);
  padding-bottom: 0.5rem;
  border-bottom: 2px solid var(--gray-200);
}

.static-content h2:first-child { margin-top: 0; }

.static-content p {
  font-size: 0.95rem;
  line-height: 1.85;
  color: var(--gray-600);
  margin-bottom: 1rem;
}

.static-content ul {
  list-style: disc;
  padding-left: 1.5rem;
  margin-bottom: 1.2rem;
}

.static-content ul li {
  font-size: 0.95rem;
  color: var(--gray-600);
  margin-bottom: 0.5rem;
}

/* Contact Form */
.contact-form {
  margin-top: 1.5rem;
}

.contact-form .form-group {
  margin-bottom: 1.2rem;
}

.contact-form textarea {
  width: 100%;
  padding: 0.8rem 1rem;
  border: 2px solid var(--gray-200);
  border-radius: 10px;
  font-size: 0.95rem;
  font-family: var(--font-main);
  color: var(--gray-800);
  background: var(--white);
  transition: var(--transition);
  outline: none;
  resize: vertical;
  min-height: 120px;
}

.contact-form textarea:focus {
  border-color: var(--black);
  box-shadow: 0 0 0 3px rgba(0,0,0,0.08);
}

.success-msg {
  display: none;
  background: #f0fdf4;
  border: 1px solid #bbf7d0;
  color: #16a34a;
  padding: 1rem;
  border-radius: 8px;
  font-size: 0.92rem;
  margin-top: 1rem;
  text-align: center;
}

.success-msg.show { display: block; }

/* ============================================
   ABOUT PAGE
   ============================================ */
.about-cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1.5rem;
  margin: 2rem 0;
}

.about-card {
  text-align: center;
  padding: 2rem 1.5rem;
  background: var(--gray-100);
  border-radius: var(--border-radius);
}

.about-card-icon {
  font-size: 2rem;
  margin-bottom: 1rem;
}

.about-card h4 {
  font-size: 1rem;
  margin-bottom: 0.5rem;
  color: var(--black);
}

.about-card p {
  font-size: 0.85rem;
  color: var(--gray-500);
}

/* ============================================
   ANIMATIONS
   ============================================ */
@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(24px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes fadeInDown {
  from { opacity: 0; transform: translateY(-16px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

.animate-fade-up {
  opacity: 0;
  animation: fadeInUp 0.6s ease forwards;
}

.animate-fade-up.delay-1 { animation-delay: 0.1s; }
.animate-fade-up.delay-2 { animation-delay: 0.2s; }
.animate-fade-up.delay-3 { animation-delay: 0.3s; }
.animate-fade-up.delay-4 { animation-delay: 0.4s; }

/* Intersection Observer animations */
.reveal {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

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

/* ============================================
   RESPONSIVE
   ============================================ */
@media (max-width: 1024px) {
  .footer-grid {
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
  }
}

@media (max-width: 768px) {
  section { padding: 3.5rem 1.2rem; }

  .nav-menu {
    display: none;
    position: absolute;
    top: 70px;
    left: 0;
    right: 0;
    background: rgba(0,0,0,0.98);
    flex-direction: column;
    padding: 1rem;
    gap: 0.3rem;
    border-top: 1px solid rgba(255,255,255,0.08);
    align-items: stretch;
  }

  .nav-menu.open { display: flex; }

  .nav-toggle { display: flex; }

  .dropdown {
    position: static;
    transform: none;
    box-shadow: none;
    border: none;
    background: rgba(255,255,255,0.04);
    border-radius: 8px;
    opacity: 1;
    visibility: visible;
    display: none;
    padding: 0.5rem;
    margin-top: 0.3rem;
  }

  .nav-item.open .dropdown { display: block; }

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

  .dropdown-item { color: rgba(255,255,255,0.7); }

  .dropdown-item:hover { background: rgba(255,255,255,0.08); color: var(--white); }

  .dropdown-item-icon { background: rgba(255,255,255,0.1); }

  .nav-link { color: rgba(255,255,255,0.8); border-radius: 8px; }
  .nav-link:hover { background: rgba(255,255,255,0.08); }

  .hero-stats { gap: 2rem; flex-wrap: wrap; }

  .footer-grid {
    grid-template-columns: 1fr;
    gap: 2rem;
  }

  .footer-bottom {
    flex-direction: column;
    text-align: center;
  }

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

  .tools-grid { grid-template-columns: repeat(auto-fill, minmax(220px, 1fr)); }

  .calc-body { padding: 1.5rem; }

  .seo-content { padding: 2rem 1.5rem; }

  .tool-desc, .faq-section, .static-content { padding: 2rem 1.5rem; }

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

@media (max-width: 480px) {
  .hero-title { letter-spacing: -1px; }
  .hero-actions { flex-direction: column; align-items: center; }
  .hero-stats { gap: 1.5rem; }
  .tools-grid { grid-template-columns: 1fr; }
  .features-grid { grid-template-columns: 1fr 1fr; }
  .result-grid { grid-template-columns: 1fr; }
}

/* ============================================
   SCROLL BAR
   ============================================ */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: var(--gray-100); }
::-webkit-scrollbar-thumb { background: var(--gray-300); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--gray-400); }

/* ============================================
   UTILITY CLASSES
   ============================================ */
.text-center { text-align: center; }
.text-white { color: var(--white); }
.text-muted { color: var(--gray-500); }
.mb-0 { margin-bottom: 0; }
.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.gap-1 { gap: 0.5rem; }

/* Page transition */
.page-enter {
  animation: fadeIn 0.4s ease;
}