:root {
    --accent-1: #ff2e93;
    --accent-2: #7b2ff7;
    --accent-3: #00e0ff;
    --accent-warm: #ffb800;
    --glass: rgba(255, 255, 255, 0.08);
    --glass-border: rgba(255, 255, 255, 0.16);
    --text: #f5f3ff;
    --text-dim: rgba(245, 243, 255, 0.72);
    --danger: #ff5c7a;
    --danger-bg: rgba(255, 92, 122, 0.18);
    --radius: 22px;

    --natural-1: #22c55e;
    --natural-2: #06b6d4;
    --artificial-1: #7b2ff7;
    --artificial-2: #00e0ff;
}

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

html, body {
    height: 100%;
}

body {
    position: relative;
    font-family: -apple-system, "Segoe UI", Roboto, Inter, Arial, sans-serif;
    background: #0a0a18;
    min-height: 100vh;
    color: var(--text);
    display: flex;
    flex-direction: column;
    overflow-x: hidden;
}

body::before {
    content: "";
    position: fixed;
    inset: -25%;
    background:
        radial-gradient(circle at 12% 18%, rgba(255, 46, 147, 0.55), transparent 42%),
        radial-gradient(circle at 88% 22%, rgba(0, 224, 255, 0.5), transparent 44%),
        radial-gradient(circle at 50% 88%, rgba(255, 184, 0, 0.4), transparent 46%),
        radial-gradient(circle at 90% 92%, rgba(123, 47, 247, 0.55), transparent 46%),
        radial-gradient(circle at 8% 85%, rgba(34, 197, 94, 0.35), transparent 42%);
    filter: blur(60px) saturate(140%);
    animation: aurora-spin 20s linear infinite;
    z-index: -1;
    pointer-events: none;
}

@keyframes aurora-spin {
    0% {
        filter: blur(60px) saturate(140%) hue-rotate(0deg);
    }
    100% {
        filter: blur(60px) saturate(140%) hue-rotate(360deg);
    }
}

.navbar {
    padding: 22px 20px;
    text-align: center;
    background: rgba(10, 10, 24, 0.45);
    border-bottom: 1px solid var(--glass-border);
    backdrop-filter: blur(10px);
    position: sticky;
    top: 0;
    z-index: 10;
}

.navbar h1 {
    font-size: clamp(20px, 4vw, 28px);
    font-weight: 800;
    letter-spacing: 0.3px;
    background: linear-gradient(90deg, var(--accent-1), var(--accent-warm), var(--accent-3));
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
}

main {
    flex: 1;
}

.container {
    width: 100%;
    min-height: 80vh;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 30px 16px;
}

.card {
    width: 100%;
    max-width: 580px;
    padding: clamp(24px, 5vw, 46px);
    background: var(--glass);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius);
    text-align: center;
    backdrop-filter: blur(16px);
    box-shadow:
        0 25px 70px rgba(0, 0, 0, 0.45),
        0 0 0 1px rgba(255, 255, 255, 0.03) inset;
    animation: rise 0.5s ease both;
    position: relative;
}

.card::before {
    content: "";
    position: absolute;
    inset: -1px;
    border-radius: var(--radius);
    padding: 1px;
    background: linear-gradient(135deg, var(--accent-1), var(--accent-3), var(--accent-warm));
    -webkit-mask: linear-gradient(#fff 0 0) content-box, linear-gradient(#fff 0 0);
    -webkit-mask-composite: xor;
    mask-composite: exclude;
    opacity: 0.5;
    pointer-events: none;
}

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

.card h2 {
    margin-bottom: 10px;
    font-size: clamp(20px, 4vw, 27px);
    font-weight: 800;
}

.description {
    margin-bottom: 28px;
    color: var(--text-dim);
    line-height: 1.5;
}

.upload-box {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 10px;
    padding: 36px 20px;
    border: 2px dashed rgba(255, 255, 255, 0.32);
    border-radius: 16px;
    cursor: pointer;
    margin-bottom: 20px;
    transition: border-color 0.2s ease, background 0.2s ease, transform 0.2s ease;
    position: relative;
    overflow: hidden;
    background: linear-gradient(160deg, rgba(255, 46, 147, 0.06), rgba(0, 224, 255, 0.06));
}

.upload-box:hover,
.upload-box:focus-within {
    background: linear-gradient(160deg, rgba(255, 46, 147, 0.14), rgba(0, 224, 255, 0.14));
    border-color: var(--accent-3);
}

.upload-box.dragover {
    background: linear-gradient(160deg, rgba(255, 184, 0, 0.18), rgba(123, 47, 247, 0.18));
    border-color: var(--accent-warm);
    transform: scale(1.015);
}

.upload-icon {
    font-size: 42px;
    line-height: 1;
    filter: drop-shadow(0 4px 12px rgba(255, 46, 147, 0.4));
}

.upload-text {
    font-weight: 700;
}

.upload-hint {
    font-size: 13px;
    color: var(--text-dim);
}

.upload-box input {
    position: absolute;
    inset: 0;
    opacity: 0;
    cursor: pointer;
}

.preview-thumb {
    display: none;
    max-width: 100%;
    max-height: 180px;
    border-radius: 12px;
    margin-top: 4px;
    object-fit: contain;
    box-shadow: 0 10px 24px rgba(0, 0, 0, 0.4);
}

.preview-thumb.visible {
    display: block;
}

button {
    width: 100%;
    padding: 16px;
    border: none;
    border-radius: 14px;
    font-size: 16px;
    font-weight: 700;
    cursor: pointer;
    color: white;
    background: linear-gradient(120deg, var(--accent-1), var(--accent-2) 50%, var(--accent-3));
    background-size: 200% 200%;
    box-shadow: 0 14px 30px rgba(123, 47, 247, 0.4);
    transition: transform 0.15s ease, box-shadow 0.15s ease, background-position 0.4s ease, opacity 0.15s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
}

button:hover {
    transform: translateY(-2px);
    background-position: 100% 0%;
    box-shadow: 0 18px 40px rgba(0, 224, 255, 0.35);
}

button:active {
    transform: translateY(0);
}

button:disabled {
    opacity: 0.7;
    cursor: progress;
    transform: none;
}

.spinner {
    display: none;
    width: 16px;
    height: 16px;
    border: 2px solid rgba(255, 255, 255, 0.4);
    border-top-color: white;
    border-radius: 50%;
    animation: spin 0.7s linear infinite;
}

button.loading .spinner {
    display: inline-block;
}

button.loading .btn-label {
    opacity: 0.85;
}

@keyframes spin {
    to {
        transform: rotate(360deg);
    }
}

.error {
    margin-top: 20px;
    padding: 14px 16px;
    border-radius: 12px;
    background: var(--danger-bg);
    border: 1px solid rgba(255, 92, 122, 0.4);
    color: #ffd6de;
    text-align: left;
}

.result {
    margin-top: 32px;
    padding-top: 26px;
    border-top: 1px solid var(--glass-border);
    animation: rise 0.4s ease both;
}

.result-image {
    width: 100%;
    max-height: 280px;
    object-fit: contain;
    border-radius: 16px;
    margin: 4px 0 22px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.45);
}

.result-badge {
    display: inline-block;
    padding: 9px 22px;
    border-radius: 999px;
    font-size: clamp(18px, 4vw, 25px);
    font-weight: 800;
    margin-bottom: 18px;
    background: linear-gradient(135deg, var(--accent-1), var(--accent-2), var(--accent-3));
    box-shadow: 0 10px 26px rgba(123, 47, 247, 0.45);
}

.result[data-label="Natural"] .result-badge {
    background: linear-gradient(135deg, var(--natural-1), var(--natural-2));
    box-shadow: 0 10px 26px rgba(34, 197, 94, 0.4);
}

.result[data-label="Artificial"] .result-badge {
    background: linear-gradient(135deg, var(--artificial-1), var(--artificial-2));
    box-shadow: 0 10px 26px rgba(0, 224, 255, 0.4);
}

.confidence-row {
    display: flex;
    justify-content: space-between;
    font-size: 13px;
    color: var(--text-dim);
    margin-bottom: 6px;
}

.confidence-track {
    width: 100%;
    height: 10px;
    border-radius: 999px;
    background: rgba(255, 255, 255, 0.12);
    overflow: hidden;
}

.confidence-fill {
    height: 100%;
    border-radius: 999px;
    background: linear-gradient(90deg, var(--accent-1), var(--accent-2), var(--accent-3));
    width: 0%;
    transition: width 0.8s ease 0.1s;
}

.result[data-label="Natural"] .confidence-fill {
    background: linear-gradient(90deg, var(--natural-1), var(--natural-2));
}

.result[data-label="Artificial"] .confidence-fill {
    background: linear-gradient(90deg, var(--artificial-1), var(--artificial-2));
}

.feedback-box {
    margin-top: 28px;
    padding-top: 22px;
    border-top: 1px dashed var(--glass-border);
}

.feedback-question {
    font-size: 14px;
    color: var(--text-dim);
    margin-bottom: 12px;
    font-weight: 600;
}

.feedback-actions,
.feedback-alt-options {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    justify-content: center;
}

.feedback-btn {
    width: auto;
    flex: 1 1 140px;
    padding: 12px 16px;
    font-size: 14px;
    border-radius: 12px;
}

.feedback-yes {
    background: linear-gradient(120deg, var(--natural-1), var(--natural-2));
    box-shadow: 0 10px 22px rgba(34, 197, 94, 0.35);
}

.feedback-no {
    background: linear-gradient(120deg, var(--danger), var(--accent-1));
    box-shadow: 0 10px 22px rgba(255, 92, 122, 0.35);
}

.feedback-alt {
    margin-top: 16px;
    animation: rise 0.3s ease both;
}

.feedback-chip {
    width: auto;
    padding: 10px 18px;
    font-size: 14px;
    border-radius: 999px;
    background: rgba(255, 255, 255, 0.1);
    border: 1px solid var(--glass-border);
    box-shadow: none;
}

.feedback-chip:hover {
    background: linear-gradient(120deg, var(--accent-2), var(--accent-3));
    transform: translateY(-1px);
}

.feedback-thanks {
    margin-top: 6px;
    font-weight: 700;
    color: #baf5cd;
}

footer {
    text-align: center;
    padding: 18px;
    color: var(--text-dim);
    font-size: 13px;
}

@media (max-width: 420px) {
    .upload-box {
        padding: 26px 14px;
    }

    .feedback-btn {
        flex: 1 1 100%;
    }
}