:root {
  --bg: #f6f6f4;
  --bg-alt: #ffffff;
  --text: #0f0f0f;
  --muted: #5f5f5f;
  --border: #dddddd;
  --line: rgba(0, 0, 0, 0.08);
  --shadow: 0 18px 40px rgba(0, 0, 0, 0.08);
  --theme-color: #f6f6f4;
  --radius: 14px;
  --transition: 240ms cubic-bezier(0.2, 0.8, 0.2, 1);
  --max-width: 1120px;
  --card-bg: linear-gradient(160deg, #ffffff 0%, #f1f1f1 100%);
  --card-hover: #ededed;
  --input-bg: #ffffff;
  --input-border: #d6d6d6;
  --preview-bg: linear-gradient(135deg, #f3f3f3, #ffffff);
  --panel-bg: #ffffff;
  --header-bg: rgba(255, 255, 255, 0.9);
  --footer-border: #dddddd;
  --button-bg: #0f0f0f;
  --button-text: #ffffff;
  --button-hover: #000000;
  --button-secondary-bg: #ffffff;
  --button-secondary-text: #0f0f0f;
  --wipe-bg: #f6f6f4;
}

[data-theme="dark"] {
  --bg: #0b0b0b;
  --bg-alt: #121212;
  --text: #f4f4f4;
  --muted: #b2b2b2;
  --border: #2a2a2a;
  --line: rgba(255, 255, 255, 0.08);
  --shadow: 0 18px 40px rgba(0, 0, 0, 0.45);
  --theme-color: #0b0b0b;
  --card-bg: linear-gradient(160deg, #181818 0%, #101010 100%);
  --card-hover: #1f1f1f;
  --input-bg: #141414;
  --input-border: #2b2b2b;
  --preview-bg: linear-gradient(135deg, #1a1a1a, #0f0f0f);
  --panel-bg: #141414;
  --header-bg: rgba(10, 10, 10, 0.88);
  --footer-border: #1f1f1f;
  --button-bg: #f4f4f4;
  --button-text: #0f0f0f;
  --button-hover: #ffffff;
  --button-secondary-bg: #0f0f0f;
  --button-secondary-text: #f4f4f4;
  --wipe-bg: #0b0b0b;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  background: var(--bg);
  overscroll-behavior-y: none;
}

body {
  margin: 0;
  font-family: "Space Grotesk", "Sora", "Helvetica Neue", Arial, sans-serif;
  color: var(--text);
  background: radial-gradient(circle at top, var(--bg-alt) 0%, var(--bg) 60%, var(--bg) 100%);
  background-color: var(--bg);
  min-height: 100vh;
  transition: background 400ms ease, color 400ms ease;
  overscroll-behavior-y: none;
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  background-image: linear-gradient(var(--line) 1px, transparent 1px),
    linear-gradient(90deg, var(--line) 1px, transparent 1px);
  background-size: 120px 120px, 120px 120px;
  pointer-events: none;
  opacity: 0.4;
  z-index: 0;
  transition: opacity 400ms ease;
}

body.theme-wipe::after {
  content: "";
  position: fixed;
  inset: 0;
  background: var(--wipe-bg);
  z-index: 9999;
  pointer-events: none;
  animation: themeWipe 700ms ease forwards;
}

@keyframes themeWipe {
  from {
    clip-path: inset(0 0 0 0);
  }
  to {
    clip-path: inset(100% 0 0 0);
  }
}

img {
  max-width: 100%;
  display: block;
}

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

header {
  border-bottom: 1px solid var(--border);
  background: var(--header-bg);
  backdrop-filter: blur(10px);
  position: sticky;
  top: 0;
  z-index: 10;
  transition: background 400ms ease, border-color 400ms ease;
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
  position: relative;
  z-index: 1;
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 20px 0;
  gap: 16px;
}

.brand {
  font-weight: 700;
  font-size: 1.5rem;
  letter-spacing: 0.02em;
}

.nav-links {
  display: flex;
  gap: 18px;
  font-size: 0.95rem;
  align-items: center;
}

.nav-links a {
  padding-bottom: 4px;
  border-bottom: 1px solid transparent;
  transition: border-color var(--transition);
}

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

.theme-toggle {
  border: 1px solid var(--border);
  background: transparent;
  color: var(--text);
  padding: 8px 16px;
  border-radius: 999px;
  font-size: 0.85rem;
  cursor: pointer;
  transition: background var(--transition), border-color var(--transition), color var(--transition);
}

.theme-toggle:hover {
  background: var(--text);
  color: var(--bg-alt);
  border-color: var(--text);
}

.hero {
  padding: 90px 0 40px;
  text-align: left;
  max-width: 820px;
}

.hero h1 {
  font-size: clamp(2.8rem, 4.5vw, 4.2rem);
  margin: 0 0 16px;
  letter-spacing: -0.02em;
}

.hero p {
  color: var(--muted);
  font-size: 1.15rem;
  max-width: 640px;
  margin: 0;
  line-height: 1.6;
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 26px;
  margin: 50px 0 90px;
}

.card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 30px;
  text-align: left;
  transition: transform var(--transition), box-shadow var(--transition), background var(--transition);
  min-height: 220px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  position: relative;
  overflow: hidden;
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow);
  background: var(--card-hover);
}

.card h3 {
  margin: 0 0 10px;
  font-size: 1.55rem;
}

.card p {
  color: var(--muted);
  margin: 0;
  line-height: 1.6;
}

.card span {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  font-size: 0.75rem;
}

.card::after {
  content: "";
  position: absolute;
  width: 120px;
  height: 120px;
  border-radius: 50%;
  background: rgba(0, 0, 0, 0.05);
  right: -40px;
  top: -40px;
  pointer-events: none;
  transition: opacity var(--transition);
}

[data-theme="dark"] .card::after {
  background: rgba(255, 255, 255, 0.06);
}

.section-title {
  margin: 40px 0 12px;
  font-size: clamp(1.7rem, 3vw, 2.3rem);
  letter-spacing: -0.01em;
}

.section-subtitle {
  margin-top: 0;
  color: var(--muted);
}

.form-card {
  background: var(--bg-alt);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 36px;
  box-shadow: 0 12px 30px rgba(0, 0, 0, 0.06);
  transition: background 400ms ease, border-color 400ms ease;
}

.form-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 18px;
  margin: 24px 0;
}

label {
  display: block;
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--muted);
  margin-bottom: 8px;
}

input[type="text"],
input[type="number"],
input[type="file"] {
  width: 100%;
  padding: 12px 14px;
  border-radius: 12px;
  border: 1px solid var(--input-border);
  background: var(--input-bg);
  color: var(--text);
  font-size: 1rem;
  transition: border-color var(--transition), box-shadow var(--transition), background var(--transition);
}

input:focus {
  outline: none;
  border-color: var(--text);
  box-shadow: 0 0 0 3px rgba(0, 0, 0, 0.08);
}

.cover-row {
  display: grid;
  grid-template-columns: minmax(140px, 180px) 1fr;
  gap: 18px;
  align-items: center;
}

.cover-preview {
  width: 100%;
  aspect-ratio: 1;
  border: 1px dashed var(--border);
  border-radius: 12px;
  background: var(--preview-bg);
  display: grid;
  place-items: center;
  color: var(--muted);
  font-size: 0.9rem;
  text-align: center;
  padding: 12px;
  position: relative;
  overflow: hidden;
}

.cover-preview img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  border-radius: 10px;
  position: absolute;
  top: 0;
  left: 0;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 22px;
  border-radius: 16px;
  border: 1px solid var(--button-bg);
  background: var(--button-bg);
  color: var(--button-text);
  font-weight: 600;
  cursor: pointer;
  transition: transform var(--transition), box-shadow var(--transition), background var(--transition);
}

.button:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow);
  background: var(--button-hover);
}

.button.secondary {
  background: var(--button-secondary-bg);
  color: var(--button-secondary-text);
  border-color: var(--border);
}

.meta-footer {
  margin-top: 20px;
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
}

.result-box {
  margin-top: 24px;
  padding: 24px;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  background: var(--panel-bg);
  text-align: center;
}

.result-key {
  font-size: 2.4rem;
  font-weight: 700;
  margin: 0 0 8px;
}

footer {
  padding: 40px 0 50px;
  color: var(--muted);
  text-align: center;
  font-size: 0.9rem;
  border-top: 1px solid var(--footer-border);
}

.fade-in {
  animation: fadeIn 700ms ease forwards;
  opacity: 0;
  transform: translateY(10px);
}

@keyframes fadeIn {
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@media (max-width: 720px) {
  .nav {
    flex-direction: column;
    gap: 12px;
  }

  .nav-links {
    flex-wrap: wrap;
    justify-content: center;
  }

  .hero {
    padding-top: 56px;
    text-align: center;
  }

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

  .meta-footer {
    flex-direction: column;
    align-items: flex-start;
  }
}