/* ===== RESET & BASE ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg:            #f0f0f0;
  --surface:       #ffffff;
  --surface-2:     #f1f5f9;
  --surface-3:     #e8edf3;
  --primary:       #3b82f6;
  --primary-hover: #2563eb;
  --primary-light: #eff6ff;
  --text:          #0f172a;
  --text-sec:      #64748b;
  --text-muted:    #94a3b8;
  --border:        #e2e8f0;
  --border-input:  #94a3b8;
  --border-focus:  #3b82f6;
  --success:       #22c55e;
  --success-bg:    #f0fdf4;
  --error:         #ef4444;
  --error-bg:      #fef2f2;
  --warning:       #f59e0b;
  --warning-bg:    #fffbeb;
  --info-bg:       #eff6ff;
  --r-sm:  6px;
  --r:     10px;
  --r-lg:  14px;
  --sh-sm: 0 1px 2px rgba(0,0,0,.05);
  --sh:    0 1px 3px rgba(0,0,0,.1), 0 1px 2px rgba(0,0,0,.06);
  --sh-md: 0 4px 6px -1px rgba(0,0,0,.1), 0 2px 4px -1px rgba(0,0,0,.06);
  --font:  -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;
  --mono:  'SF Mono', 'Fira Code', 'Roboto Mono', 'Consolas', monospace;
}

html { scroll-behavior: smooth; }

body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--primary); text-decoration: none; }
a:hover { text-decoration: underline; }

/* ===== NAVIGATION ===== */
.nav {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
}
.nav-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 1.5rem;
  height: 56px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  position: relative;
}
.nav-logo {
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--text);
  text-decoration: none;
  letter-spacing: -0.01em;
  flex-shrink: 0;
}
.nav-logo span { color: var(--primary); }
.nav-links {
  list-style: none;
  display: flex;
  gap: 0.125rem;
  align-items: center;
}
.nav-links a {
  color: var(--text-sec);
  font-size: 0.875rem;
  font-weight: 500;
  padding: 0.375rem 0.75rem;
  border-radius: var(--r-sm);
  text-decoration: none;
  transition: color .15s, background .15s;
  white-space: nowrap;
}
.nav-links a:hover { color: var(--text); background: var(--surface-2); }
.nav-links a.active { color: var(--primary); background: var(--primary-light); }
.nav-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.5rem;
  color: var(--text);
  font-size: 1.25rem;
  line-height: 1;
}

/* ===== MAIN ===== */
main {
  flex: 1;
  max-width: 1100px;
  margin: 0 auto;
  width: 100%;
  padding: 2rem 1.5rem;
}

/* ===== FOOTER ===== */
footer {
  background: var(--surface);
  border-top: 1px solid var(--border);
  padding: 1.25rem 1.5rem;
  text-align: center;
  color: var(--text-sec);
  font-size: 0.875rem;
}
footer a { color: var(--text-sec); text-decoration: none; }
footer a:hover { color: var(--primary); }
.footer-sep { margin: 0 0.5rem; opacity: .4; }

/* ===== TYPOGRAPHY ===== */
h1 { font-size: 2rem; font-weight: 700; letter-spacing: -.025em; line-height: 1.2; }
h2 { font-size: 1.375rem; font-weight: 600; letter-spacing: -.02em; margin-bottom: .75rem; }
h3 { font-size: 1.0625rem; font-weight: 600; margin-bottom: .375rem; }

.page-header { margin-bottom: 2rem; }
.page-header h1 { margin-bottom: .375rem; }
.page-header p { color: var(--text-sec); font-size: 1.0625rem; }

/* ===== CARD ===== */
.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--r-lg);
  padding: 1.5rem;
  box-shadow: var(--sh-sm);
}
.card-title {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-sec);
  text-transform: uppercase;
  letter-spacing: .06em;
  font-size: .75rem;
  margin-bottom: 1rem;
  display: flex;
  align-items: center;
  gap: .5rem;
}
.card-title::before {
  content: '';
  display: block;
  width: 3px;
  height: 14px;
  background: var(--primary);
  border-radius: 2px;
}

/* ===== BUTTONS ===== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: .375rem;
  padding: .5rem 1.125rem;
  border-radius: var(--r-sm);
  font-size: .9rem;
  font-weight: 500;
  cursor: pointer;
  border: none;
  transition: background .15s, opacity .15s, transform .1s, border-color .15s;
  white-space: nowrap;
  font-family: var(--font);
  line-height: 1.4;
  text-decoration: none;
}
.btn:active { transform: scale(.98); }
.btn:focus-visible { outline: 2px solid var(--primary); outline-offset: 2px; }

.btn-primary { background: var(--primary); color: #fff; }
.btn-primary:hover { background: var(--primary-hover); text-decoration: none; }

.btn-secondary {
  background: var(--surface);
  color: var(--text);
  border: 1px solid var(--border);
}
.btn-secondary:hover { background: var(--surface-2); }

.btn-sm { padding: .3rem .75rem; font-size: .8125rem; }
.btn-icon {
  padding: .4rem .6rem;
  font-size: .8rem;
  background: var(--surface-2);
  color: var(--text-sec);
  border: 1px solid var(--border);
}
.btn-icon:hover { background: var(--surface-3); color: var(--text); }

/* Copy disabled */
.btn-copy:disabled { cursor: not-allowed; }
.btn-copy:disabled:hover { background: var(--surface-2) !important; color: var(--text-sec) !important; }
.btn-copy:disabled:active { transform: none; }

/* Copy feedback */
.btn-copy.copied {
  background: var(--success-bg) !important;
  color: #15803d !important;
  border-color: #86efac !important;
}

/* ===== FORM ELEMENTS ===== */
label {
  display: block;
  font-size: .875rem;
  font-weight: 500;
  color: var(--text-sec);
  margin-bottom: .375rem;
}
input[type="text"],
input[type="number"],
textarea,
select {
  width: 100%;
  padding: .5625rem .75rem;
  border: 1px solid var(--border-input);
  border-radius: var(--r-sm);
  font-size: .9375rem;
  font-family: var(--font);
  color: var(--text);
  background: var(--surface);
  box-shadow: inset 0 1px 3px rgba(0,0,0,.07);
  transition: border-color .15s, box-shadow .15s;
  outline: none;
  -webkit-appearance: none;
}
input:focus, textarea:focus, select:focus {
  border-color: var(--border-focus);
  box-shadow: 0 0 0 3px rgba(59,130,246,.12);
}
input[readonly], textarea[readonly] {
  background: var(--surface-2);
  cursor: default;
  color: var(--text-sec);
}
textarea[readonly] {
  background: var(--surface-3);
}
textarea {
  resize: vertical;
  min-height: 110px;
  font-family: var(--mono);
  font-size: .875rem;
  line-height: 1.6;
}

.form-group { margin-bottom: 1rem; }
.form-row {
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  gap: .625rem;
  margin-bottom: 1rem;
}
.form-row label { font-size: .8125rem; }
.form-row input { font-size: .875rem; padding: .5rem .625rem; }

.input-row {
  display: flex;
  gap: .5rem;
  align-items: flex-start;
}
.input-row input { flex: 1; }

/* ===== RESULTS ===== */
.result-box {
  margin-top: 1rem;
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: var(--r-sm);
  overflow: hidden;
}
.result-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: .75rem;
  padding: .6rem 1rem;
}
.result-row + .result-row { border-top: 1px solid var(--border); }
.result-label {
  font-size: .8125rem;
  color: var(--text-sec);
  font-weight: 500;
  white-space: nowrap;
  flex-shrink: 0;
}
.result-value {
  font-family: var(--mono);
  font-size: .875rem;
  color: var(--text);
  word-break: break-all;
  text-align: right;
}

/* ===== ALERTS ===== */
.alert {
  padding: .625rem .875rem;
  border-radius: var(--r-sm);
  font-size: .875rem;
  display: none;
}
.alert.visible { display: block; }
.alert-error   { background: var(--error-bg);   color: #b91c1c; border: 1px solid #fecaca; }
.alert-warning { background: var(--warning-bg); color: #92400e; border: 1px solid #fde68a; }
.alert-info    { background: var(--info-bg);    color: #1d4ed8; border: 1px solid #bfdbfe; }

/* ===== TOGGLE / SWITCHER ===== */
.toggle-wrap {
  display: flex;
  align-items: center;
  gap: .5rem;
  margin-bottom: 1.25rem;
}
.toggle-label {
  font-size: .875rem;
  font-weight: 500;
  color: var(--text-sec);
}
.toggle-group {
  display: flex;
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: var(--r-sm);
  padding: 2px;
  gap: 2px;
}
.toggle-btn {
  padding: .3rem .875rem;
  border-radius: calc(var(--r-sm) - 2px);
  font-size: .8125rem;
  font-weight: 500;
  cursor: pointer;
  border: none;
  background: transparent;
  color: var(--text-sec);
  transition: background .15s, color .15s, box-shadow .15s;
  font-family: var(--font);
}
.toggle-btn.active {
  background: var(--primary);
  color: #fff;
  font-weight: 600;
  box-shadow: var(--sh-sm);
}

/* ===== TOOLTIP ===== */
.tooltip-wrap {
  position: relative;
  display: inline-flex;
  align-items: center;
}
.tooltip-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 17px;
  height: 17px;
  border-radius: 50%;
  background: var(--surface-2);
  border: 1px solid var(--border);
  font-size: 10px;
  line-height: 17px;
  font-weight: 700;
  color: var(--text-sec);
  cursor: default;
  user-select: none;
  flex-shrink: 0;
}
.tooltip-popup {
  display: none;
  position: absolute;
  bottom: calc(100% + 8px);
  left: 50%;
  transform: translateX(-50%);
  background: #1e293b;
  color: #f1f5f9;
  font-size: .8125rem;
  padding: .5rem .75rem;
  border-radius: var(--r-sm);
  width: 240px;
  z-index: 50;
  line-height: 1.5;
  pointer-events: none;
}
.tooltip-popup::after {
  content: '';
  position: absolute;
  top: 100%;
  left: 50%;
  transform: translateX(-50%);
  border: 5px solid transparent;
  border-top-color: #1e293b;
}
.tooltip-wrap:hover .tooltip-popup,
.tooltip-wrap.open .tooltip-popup { display: block; }

/* ===== LIVE TIMESTAMP (timestamp.html) ===== */
.live-block {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}
.ts-row {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: .75rem;
}
.ts-val {
  font-family: var(--mono);
  font-size: 2.25rem;
  font-weight: 700;
  color: var(--text);
  letter-spacing: -.03em;
  line-height: 1;
  min-width: 11ch;
}
.ts-ms .ts-val {
  font-size: 1.25rem;
  color: var(--text-sec);
}
.ts-sublabel {
  font-size: .8125rem;
  color: var(--text-muted);
  margin-top: .625rem;
}

/* ===== INDEX PAGE TOOL CARDS ===== */
.hero { margin-bottom: 2.5rem; }
.hero h1 { margin-bottom: .5rem; }
.hero p  { color: var(--text-sec); font-size: 1.0625rem; max-width: 560px; }

.tools-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(270px, 1fr));
  gap: 1rem;
}
.tool-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--r-lg);
  padding: 1.5rem;
  transition: border-color .2s, box-shadow .2s, transform .2s;
  position: relative;
  color: inherit;
  display: block;
  text-decoration: none !important;
}
a.tool-card:hover {
  border-color: var(--primary);
  box-shadow: var(--sh-md);
  transform: translateY(-2px);
}
.tool-card.coming-soon { opacity: .6; cursor: default; }
.tool-icon {
  font-size: 2rem;
  margin-bottom: .875rem;
  line-height: 1;
  display: block;
}
.tool-card h3 { font-size: 1.0625rem; margin-bottom: .25rem; }
.tool-card p  { color: var(--text-sec); font-size: .875rem; line-height: 1.5; margin-bottom: .75rem; }
.badge {
  display: inline-block;
  padding: .175rem .5rem;
  border-radius: 999px;
  font-size: .75rem;
  font-weight: 600;
  letter-spacing: .03em;
}
.badge-soon {
  background: var(--surface-2);
  color: var(--text-muted);
  border: 1px solid var(--border);
}
.badge-new {
  background: var(--primary-light);
  color: var(--primary);
  border: 1px solid #bfdbfe;
}

/* ===== BASE64 PAGE ===== */
.codec-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.25rem;
}
.codec-panel h3 {
  font-size: .9375rem;
  margin-bottom: .875rem;
  display: flex;
  align-items: center;
  gap: .375rem;
}
.arrow {
  position: relative;
  top: -0.2em;
}
.codec-panel h3 .direction {
  position: relative;
  top: -0.2em;
}
.textarea-wrap {
  position: relative;
}
.textarea-copy {
  position: absolute;
  top: .5rem;
  right: .5rem;
}

/* ===== SEO SECTION ===== */
.seo-section {
  margin-top: 3rem;
  padding-top: 2rem;
  border-top: 1px solid var(--border);
  color: var(--text-sec);
}
.seo-section h2 { font-size: 1.25rem; color: var(--text); margin-bottom: .5rem; }
.seo-section h3 { font-size: 1.0625rem; color: var(--text); margin-top: 1.5rem; margin-bottom: .375rem; }
.seo-section p  { font-size: .9375rem; line-height: 1.75; margin-bottom: .875rem; }

/* ===== ABOUT / PRIVACY PAGES ===== */
.prose { max-width: 720px; }
.prose h2 { margin-top: 2rem; }
.prose p  { color: var(--text-sec); font-size: .9375rem; line-height: 1.75; margin-bottom: 1rem; }
.prose ul {
  color: var(--text-sec);
  font-size: .9375rem;
  line-height: 1.75;
  margin-bottom: 1rem;
  padding-left: 1.5rem;
}
.prose ul li { margin-bottom: .25rem; }
.prose a { color: var(--primary); }

/* ===== RESPONSIVE ===== */
@media (max-width: 768px) {
  .codec-grid { grid-template-columns: 1fr; }
  .form-row { grid-template-columns: repeat(3, 1fr); }
}

@media (max-width: 640px) {
  h1 { font-size: 1.625rem; }
  .nav-links { display: none; flex-direction: column; position: absolute; top: 56px; left: 0; right: 0;
    background: var(--surface); border-bottom: 1px solid var(--border); padding: .5rem; gap: .125rem; }
  .nav-links.open { display: flex; }
  .nav-links a { padding: .5rem .75rem; display: inline-block; }
  .nav-toggle { display: block; }
  .ts-val { font-size: 1.75rem; }
  .ts-ms .ts-val { font-size: 1rem; }
  main { padding: 1.25rem 1rem; }
  .card { padding: 1.25rem; }
  .input-row { flex-direction: column; }
  .input-row input { width: 100%; }
  .form-row { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 400px) {
  .form-row { grid-template-columns: 1fr 1fr; }
}