@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;800&display=swap');

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

body {
    font-family: 'Inter', sans-serif;
    background: #0f0f13;
    color: #e4e4e7;
}

textarea:focus, input:focus { outline: none; }

/* Header */
.site-header {
    background: linear-gradient(135deg, #1a1a2e 0%, #16213e 100%);
    border-bottom: 1px solid rgba(255,255,255,0.06);
    padding: 1rem 0;
}

.site-header .container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 1.5rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    text-decoration: none;
    color: #fff;
    font-weight: 800;
    font-size: 1.25rem;
}

.logo-icon {
    width: 36px;
    height: 36px;
    background: linear-gradient(135deg, #6366f1, #8b5cf6);
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.1rem;
}

nav a {
    color: #a1a1aa;
    text-decoration: none;
    font-size: 0.875rem;
    font-weight: 500;
    transition: color 0.2s;
    margin-left: 1.5rem;
}

nav a:hover { color: #fff; }

/* Hero */
.hero {
    text-align: center;
    padding: 3rem 1.5rem 1rem;
}

.hero h1 {
    font-size: 2.5rem;
    font-weight: 800;
    background: linear-gradient(135deg, #c084fc, #818cf8, #6366f1);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 0.75rem;
}

.hero p {
    color: #a1a1aa;
    font-size: 1.1rem;
    max-width: 500px;
    margin: 0 auto;
}

/* Container */
.container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 1.5rem;
}

/* Card */
.card {
    background: #1a1a2e;
    border: 1px solid rgba(255,255,255,0.06);
    border-radius: 1rem;
    padding: 2rem;
    box-shadow: 0 8px 32px rgba(0,0,0,0.3);
}

/* Textarea */
.input-label {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 0.5rem;
}

.input-label span {
    font-weight: 600;
    color: #e4e4e7;
}

.char-count {
    font-size: 0.8rem;
    color: #71717a;
}

textarea {
    width: 100%;
    background: #0f0f13;
    border: 1px solid rgba(255,255,255,0.1);
    border-radius: 0.75rem;
    padding: 1rem;
    color: #e4e4e7;
    font-family: 'Inter', sans-serif;
    font-size: 0.95rem;
    line-height: 1.6;
    resize: vertical;
    transition: border-color 0.2s;
}

textarea:focus {
    border-color: #6366f1;
    box-shadow: 0 0 0 3px rgba(99,102,241,0.15);
}

textarea::placeholder { color: #52525b; }

/* Buttons */
.btn-row {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
    margin-top: 1rem;
}

.btn-primary {
    background: linear-gradient(135deg, #6366f1, #8b5cf6);
    color: #fff;
    border: none;
    padding: 0.75rem 1.75rem;
    border-radius: 0.75rem;
    font-weight: 700;
    font-size: 0.95rem;
    cursor: pointer;
    transition: transform 0.15s, box-shadow 0.15s;
    font-family: 'Inter', sans-serif;
}

.btn-primary:hover {
    transform: translateY(-1px);
    box-shadow: 0 4px 20px rgba(99,102,241,0.4);
}

.btn-primary:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none;
    box-shadow: none;
}

.btn-secondary {
    background: rgba(255,255,255,0.06);
    color: #a1a1aa;
    border: 1px solid rgba(255,255,255,0.08);
    padding: 0.75rem 1.25rem;
    border-radius: 0.75rem;
    font-weight: 600;
    font-size: 0.875rem;
    cursor: pointer;
    transition: background 0.2s, color 0.2s;
    font-family: 'Inter', sans-serif;
}

.btn-secondary:hover {
    background: rgba(255,255,255,0.1);
    color: #e4e4e7;
}

/* Results */
.results-section {
    border-top: 1px solid rgba(255,255,255,0.06);
    margin-top: 2rem;
    padding-top: 2rem;
}

.results-title {
    font-size: 1.25rem;
    font-weight: 700;
    color: #e4e4e7;
    margin-bottom: 1.25rem;
}

/* Score Card */
.score-card {
    border-radius: 1rem;
    padding: 2rem;
    text-align: center;
}

.score-card .score-value {
    font-size: 3.5rem;
    font-weight: 800;
    line-height: 1;
    margin-bottom: 0.25rem;
}

.score-card .score-label {
    font-size: 0.875rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.score-high-ai {
    background: linear-gradient(135deg, rgba(239,68,68,0.15), rgba(239,68,68,0.05));
    border: 1px solid rgba(239,68,68,0.2);
}
.score-high-ai .score-value { color: #f87171; }
.score-high-ai .score-label { color: #fca5a5; }

.score-mixed {
    background: linear-gradient(135deg, rgba(234,179,8,0.15), rgba(234,179,8,0.05));
    border: 1px solid rgba(234,179,8,0.2);
}
.score-mixed .score-value { color: #facc15; }
.score-mixed .score-label { color: #fde047; }

.score-human {
    background: linear-gradient(135deg, rgba(34,197,94,0.15), rgba(34,197,94,0.05));
    border: 1px solid rgba(34,197,94,0.2);
}
.score-human .score-value { color: #4ade80; }
.score-human .score-label { color: #86efac; }

/* Progress Bars */
.bar-group {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    justify-content: center;
}

.bar-item label {
    display: flex;
    justify-content: space-between;
    font-size: 0.85rem;
    color: #a1a1aa;
    margin-bottom: 0.35rem;
}

.bar-item label strong {
    color: #e4e4e7;
    font-weight: 700;
}

.bar-track {
    width: 100%;
    height: 10px;
    background: rgba(255,255,255,0.06);
    border-radius: 999px;
    overflow: hidden;
}

.bar-fill {
    height: 100%;
    border-radius: 999px;
    transition: width 0.7s ease;
}

.bar-fill-red { background: linear-gradient(90deg, #ef4444, #f87171); }
.bar-fill-green { background: linear-gradient(90deg, #22c55e, #4ade80); }
.bar-fill-yellow { background: linear-gradient(90deg, #eab308, #facc15); }

/* Metrics Grid */
.metrics-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 0.75rem;
    margin: 1.5rem 0;
}

.metric-box {
    background: rgba(255,255,255,0.03);
    border: 1px solid rgba(255,255,255,0.06);
    border-radius: 0.75rem;
    padding: 1rem;
    text-align: center;
}

.metric-box .value {
    font-size: 1.5rem;
    font-weight: 800;
    color: #c084fc;
}

.metric-box .label {
    font-size: 0.7rem;
    color: #71717a;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-top: 0.25rem;
}

/* Sentence Highlighting */
.highlight-section h3 {
    font-weight: 600;
    color: #e4e4e7;
    margin-bottom: 0.75rem;
    font-size: 0.95rem;
}

.highlight-box {
    background: rgba(255,255,255,0.03);
    border: 1px solid rgba(255,255,255,0.06);
    border-radius: 0.75rem;
    padding: 1.25rem;
    line-height: 1.8;
    font-size: 0.9rem;
}

.sentence-ai {
    background: rgba(239,68,68,0.2);
    border-radius: 4px;
    padding: 2px 4px;
}

.sentence-mixed {
    background: rgba(234,179,8,0.2);
    border-radius: 4px;
    padding: 2px 4px;
}

.sentence-human {
    background: rgba(34,197,94,0.2);
    border-radius: 4px;
    padding: 2px 4px;
}

.legend {
    display: flex;
    gap: 1.25rem;
    margin-top: 0.75rem;
    font-size: 0.75rem;
    color: #71717a;
}

.legend-dot {
    width: 12px;
    height: 12px;
    border-radius: 3px;
    display: inline-block;
    margin-right: 4px;
    vertical-align: middle;
}

/* Ad Slot */
.ad-slot {
    min-height: 90px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(255,255,255,0.02);
    border: 1px dashed rgba(255,255,255,0.08);
    border-radius: 0.75rem;
    color: #3f3f46;
    font-size: 0.75rem;
    margin: 1.5rem 0;
}
.ad-slot:empty::after { content: "Ad Space"; }

/* SEO Content Section */
.content-section {
    margin-top: 2rem;
}

.content-section h2 {
    font-size: 1.5rem;
    font-weight: 800;
    color: #e4e4e7;
    margin-bottom: 1rem;
}

.content-section h3 {
    font-size: 1.1rem;
    font-weight: 700;
    color: #c4c4cc;
    margin-top: 1.5rem;
    margin-bottom: 0.5rem;
}

.content-section p,
.content-section li {
    color: #a1a1aa;
    line-height: 1.7;
    margin-bottom: 0.5rem;
}

.content-section ul {
    padding-left: 1.5rem;
}

.content-section details {
    margin-bottom: 0.5rem;
}

.content-section summary {
    cursor: pointer;
    font-weight: 600;
    color: #c4c4cc;
    padding: 0.5rem 0;
}

.content-section details p {
    margin-left: 1rem;
    margin-top: 0.25rem;
}

/* Footer */
.site-footer {
    border-top: 1px solid rgba(255,255,255,0.06);
    padding: 2rem 0;
    margin-top: 3rem;
}

.site-footer .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 1rem;
}

.site-footer p {
    color: #52525b;
    font-size: 0.8rem;
}

.site-footer nav a {
    color: #52525b;
    font-size: 0.8rem;
    margin-left: 1.25rem;
}

.site-footer nav a:hover { color: #a1a1aa; }

.hidden { display: none !important; }

@media (max-width: 768px) {
    .hero h1 { font-size: 1.75rem; }
    .card { padding: 1.25rem; }
    .metrics-grid { grid-template-columns: repeat(2, 1fr); }
    .score-card .score-value { font-size: 2.5rem; }
    nav { display: none; }
    .site-footer .container { flex-direction: column; text-align: center; }
    .site-footer nav a { margin-left: 0; margin-right: 1rem; }
}

@media (max-width: 480px) {
    .hero h1 { font-size: 1.5rem; }
    .btn-row { flex-direction: column; }
    .btn-primary, .btn-secondary { width: 100%; text-align: center; }
}