*, *::before, *::after {
  box-sizing: border-box;
}

[hidden] { display: none !important; }

:root {
  --bg:           #0f172a;
  --card:         #1e293b;
  --border:       #334155;
  --text:         #f1f5f9;
  --text-muted:   #94a3b8;
  --accent:       #3b82f6;
  --accent-hover: #2563eb;
  --success:      #22c55e;
  --error:        #ef4444;
  --warning:      #f59e0b;
}

body {
  margin: 0;
  padding: 24px 16px;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  background-color: var(--bg);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen,
               Ubuntu, Cantarell, "Helvetica Neue", Arial, sans-serif;
  font-size: 15px;
  color: var(--text);
  line-height: 1.5;
}

.card {
  width: 100%;
  max-width: 520px;
  background: var(--card);
  border-radius: 12px;
  box-shadow: 0 25px 50px rgba(0, 0, 0, 0.5), 0 0 0 1px rgba(255,255,255,0.04);
  overflow: hidden;
}

/* ── Header ── */
header {
  padding: 32px 32px 24px;
  border-bottom: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
}

.logo {
  width: 40px;
  height: 40px;
  color: var(--accent);
}

header h1 {
  margin: 0;
  font-size: 1.25rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  text-align: center;
}

.tagline {
  margin: 0;
  font-size: 0.875rem;
  color: var(--text-muted);
  text-align: center;
}

/* ── Sections ── */
#auth-section,
#upload-section {
  padding: 28px 32px 32px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

/* ── Labels ── */
label {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-muted);
  display: block;
  margin-bottom: 4px;
}

/* ── Inputs ── */
input[type="password"],
input[type="text"] {
  width: 100%;
  padding: 10px 14px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 6px;
  color: var(--text);
  font-size: 0.9375rem;
  outline: none;
  transition: border-color 0.15s ease, box-shadow 0.15s ease;
}

input[type="password"]:focus,
input[type="text"]:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.25);
}

input[type="file"] {
  position: absolute;
  width: 1px;
  height: 1px;
  opacity: 0;
  pointer-events: none;
}

/* ── Buttons ── */
button {
  appearance: none;
  border: none;
  cursor: pointer;
  font-family: inherit;
  font-size: 0.9375rem;
  font-weight: 600;
  border-radius: 6px;
  padding: 11px 16px;
  transition: background-color 0.15s ease, opacity 0.15s ease;
}

#verify-btn,
#upload-btn {
  width: 100%;
  background: var(--accent);
  color: #fff;
}

#verify-btn:hover:not(:disabled),
#upload-btn:hover:not(:disabled) {
  background: var(--accent-hover);
}

#verify-btn:disabled,
#upload-btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

/* ── Drop zone ── */
#drop-zone {
  border: 2px dashed var(--border);
  border-radius: 8px;
  padding: 36px 20px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  cursor: default;
  transition: border-color 0.2s ease, background-color 0.2s ease;
  text-align: center;
}

#drop-zone svg {
  width: 40px;
  height: 40px;
  color: var(--text-muted);
  flex-shrink: 0;
}

#drop-zone.dragover {
  border-color: var(--accent);
  background-color: rgba(59, 130, 246, 0.06);
}

.drop-label {
  margin: 0;
  font-weight: 500;
  color: var(--text);
}

.drop-sub {
  margin: 0;
  font-size: 0.875rem;
  color: var(--text-muted);
}

#browse-btn {
  background: none;
  border: none;
  padding: 0;
  color: var(--accent);
  font-size: 0.875rem;
  font-weight: 600;
  cursor: pointer;
  text-decoration: underline;
  text-underline-offset: 2px;
}

#browse-btn:hover {
  color: var(--accent-hover);
}

/* ── File list ── */
#file-list {
  margin: 0;
  padding: 0 0 0 4px;
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

#file-list li {
  font-size: 0.875rem;
  color: var(--text-muted);
  padding: 6px 10px;
  background: var(--bg);
  border-radius: 4px;
  word-break: break-all;
}

/* ── Progress bar ── */
#progress-bar {
  height: 6px;
  border-radius: 3px;
  background: var(--border);
  overflow: hidden;
}

#progress-fill {
  height: 100%;
  width: 0%;
  background: var(--accent);
  border-radius: 3px;
  transition: width 0.1s linear;
}

/* ── Messages ── */
.message {
  margin: 0;
  padding: 10px 14px;
  border-radius: 6px;
  font-size: 0.875rem;
  font-weight: 500;
}

.message.success {
  background: rgba(34, 197, 94, 0.1);
  color: var(--success);
}

.message.error {
  background: rgba(239, 68, 68, 0.1);
  color: var(--error);
}

/* ── Result links ── */
.result-links {
  margin: 0;
  padding: 0 0 0 4px;
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.result-links li {
  font-size: 0.875rem;
}

.result-links a {
  color: var(--accent);
  text-decoration: underline;
  text-underline-offset: 2px;
  word-break: break-all;
}

.result-links a:hover {
  color: var(--accent-hover);
}

/* ── Upload result container ── */
#upload-result {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

/* ── Link verification loading state ── */
.verifying-msg {
  margin: 28px 32px;
  font-size: 0.9375rem;
  color: var(--text-muted);
  text-align: center;
}

/* ── Generate link section ── */
.section-divider {
  height: 1px;
  background: var(--border);
  margin: 4px 0;
}

.link-heading {
  margin: 0;
  font-size: 0.9375rem;
  font-weight: 600;
  color: var(--text);
}

.link-sub {
  margin: 0;
  font-size: 0.8125rem;
  color: var(--text-muted);
}

#generate-btn {
  width: 100%;
  background: transparent;
  color: var(--accent);
  border: 1px solid var(--accent);
  border-radius: 6px;
  padding: 10px 16px;
  font-weight: 600;
  font-size: 0.9375rem;
  transition: background-color 0.15s ease, color 0.15s ease;
}

#generate-btn:hover:not(:disabled) {
  background: var(--accent);
  color: #fff;
}

#generate-btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.link-output-row {
  display: flex;
  gap: 8px;
}

.link-output-row input {
  flex: 1;
  font-size: 0.8125rem;
  color: var(--text-muted);
  cursor: text;
}

#copy-btn {
  flex-shrink: 0;
  background: var(--border);
  color: var(--text);
  border-radius: 6px;
  padding: 10px 16px;
  font-size: 0.875rem;
  font-weight: 600;
  transition: background-color 0.15s ease;
}

#copy-btn:hover {
  background: #475569;
}

/* ── Responsive ── */
@media (max-width: 560px) {
  #auth-section,
  #upload-section {
    padding: 20px 20px 24px;
  }

  header {
    padding: 24px 20px 20px;
  }
}