/* Biến nội bộ */
.radio-neo-wrapper {
    --bg-white: #ffffff;
    --border-ink: 3px solid #111111;
    --shadow-solid: 5px 5px 0px #111111;
    --shadow-push: 2px 2px 0px #111111;
    
    /* Bảng màu Phóng Xạ */
    --clr-toxic: #aacc00;    /* Xanh phóng xạ */
    --clr-dark: #111111;     /* Đen */
    --clr-danger: #d00000;   /* Đỏ cảnh báo */
    --clr-safe: #00b4d8;     /* Xanh lam */
    --clr-bg: #f8f9fa;

    max-width: 850px;
    margin: 0 auto;
    font-family: system-ui, -apple-system, sans-serif;
    color: var(--clr-dark);
    background: var(--clr-bg);
    padding: 20px;
    border: var(--border-ink);
    border-radius: 16px;
    box-shadow: 8px 8px 0px var(--clr-dark);
}

.radio-neo-wrapper * { box-sizing: border-box; }

.radio-neo-header { background: var(--clr-toxic); border: var(--border-ink); box-shadow: var(--shadow-solid); padding: 20px; border-radius: 12px; text-align: center; margin-bottom: 25px; }
.radio-neo-header h2 { margin: 0 0 10px 0; font-size: 1.8rem; font-weight: 900; text-transform: uppercase; letter-spacing: 1px;}
.radio-neo-header p { margin: 0; font-weight: 800; font-size: 0.95rem; }

.radio-neo-form { display: flex; flex-direction: column; gap: 20px; }
.radio-form-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; }
.radio-group { display: flex; flex-direction: column; gap: 10px; }
.radio-group label { font-weight: 900; font-size: 1.05rem; }

/* CSS FIX CHUẨN Ô INPUT & SELECT */
.input-with-select { 
    display: flex; flex-wrap: nowrap; align-items: stretch; border: var(--border-ink); border-radius: 12px; box-shadow: 4px 4px 0px var(--clr-dark); background: #fff; overflow: hidden; width: 100%;
}
.input-with-select input { 
    border: none !important; border-radius: 0 !important; box-shadow: none !important; flex: 1; width: 100%; min-width: 50%; padding: 16px 15px !important; font-size: 1.3rem !important; font-weight: 900; color: var(--clr-dark); outline: none;
}
.input-with-select select { 
    border: none; border-left: 3px solid var(--clr-dark); padding: 0 15px; font-weight: 900; font-size: 1.1rem; background: #e9ecef; outline: none; cursor: pointer; color: var(--clr-dark); flex: 0 0 auto; width: 100px; text-align: center;
}
.input-with-select select:disabled { opacity: 1; background: #e9ecef;}
.input-with-select input:focus, .input-with-select select:focus { background: #e0fbfc; }

/* Quick Tags */
.input-with-quick { display: flex; flex-direction: column; gap: 10px; }
.quick-tags { display: flex; gap: 8px; flex-wrap: wrap; }
.q-tag { padding: 4px 12px; border: 2px solid var(--clr-dark); border-radius: 20px; font-size: 0.85rem; font-weight: 800; cursor: pointer; background: #fff; box-shadow: 2px 2px 0px var(--clr-dark); transition: transform 0.1s;}
.q-tag:hover { background: var(--clr-toxic); }
.q-tag:active { box-shadow: 0px 0px 0px var(--clr-dark); transform: translate(2px,2px); }

.radio-helper-black { font-size: 0.95rem; font-weight: 800; background: #e9ecef; padding: 12px 15px; border-radius: 8px; border: 2px dashed var(--clr-dark); line-height: 1.5; }
.radio-error-alert { background: var(--clr-danger); color: #fff; border: var(--border-ink); padding: 12px; border-radius: 8px; font-weight: 800; text-align: center; }

/* Button */
.radio-neo-btn { padding: 18px; font-size: 1.2rem; font-weight: 900; background: var(--clr-dark); color: #fff; border: var(--border-ink); border-radius: 12px; box-shadow: 5px 5px 0px var(--clr-toxic); cursor: pointer; text-transform: uppercase; transition: all 0.1s; margin-top: 5px; letter-spacing: 1px;}
.radio-neo-btn:active { box-shadow: 2px 2px 0px var(--clr-toxic); transform: translate(3px, 3px); }

/* Result Layout */
.radio-neo-result { margin-top: 30px; padding-top: 25px; border-top: 4px dashed var(--clr-dark); display: flex; flex-direction: column; gap: 20px;}
.radio-neo-result.active { display: flex !important; animation: radAnim 0.5s cubic-bezier(0.175, 0.885, 0.32, 1.275) forwards; }

.radio-result-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 15px; }
.radio-card { border: var(--border-ink); box-shadow: var(--shadow-solid); border-radius: 12px; padding: 25px 15px; text-align: center; display: flex; flex-direction: column; justify-content: center; align-items: center;}
.card-main { background: var(--clr-toxic); color: var(--clr-dark); }
.card-sub { background: #fff; }

.radio-card h4 { margin: 0 0 10px 0; font-size: 1.1rem; font-weight: 900; text-transform: uppercase;}
.val-text { font-size: 2.8rem; font-weight: 900; line-height: 1.2; margin-bottom: 5px; word-break: break-all;}
.val-text small { font-size: 1.1rem; font-weight: 900; margin-left: 5px;}
.val-text.text-danger { color: var(--clr-danger); }
.val-desc { margin: 0; font-size: 0.95rem; font-weight: 800; color: #444; }

/* Hướng dẫn giải */
.radio-solution-box { background: #fff; border: var(--border-ink); border-radius: 12px; padding: 20px; box-shadow: var(--shadow-solid);}
.radio-solution-box h3 { margin: 0 0 15px 0; font-size: 1.2rem; font-weight: 900; text-transform: uppercase; border-bottom: 3px solid var(--clr-dark); padding-bottom: 10px;}
.step-box p { font-size: 1.05rem; font-weight: 800; margin: 8px 0 10px 0; }
.math-line { font-family: monospace, system-ui; font-size: 1.15rem !important; font-weight: 900 !important; color: var(--clr-danger) !important; background: #f8f9fa; padding: 15px; border-radius: 8px; border: 2px solid var(--clr-dark); overflow-x: auto;}

/* CANVAS ĐỒ THỊ */
.radio-canvas-box { background: #fff; border: var(--border-ink); border-radius: 12px; padding: 20px; box-shadow: var(--shadow-solid); text-align: center;}
.radio-canvas-box h3 { margin: 0 0 15px 0; font-size: 1.2rem; font-weight: 900; text-transform: uppercase;}
#radioCanvas { width: 100%; max-width: 100%; height: auto; border: 2px solid var(--clr-dark); border-radius: 8px; background: #fafafa;}

.canvas-legend { display: flex; justify-content: center; gap: 20px; margin-top: 15px; flex-wrap: wrap;}
.lg-item { display: flex; align-items: center; gap: 8px; font-weight: 800; font-size: 0.95rem;}
.lg-color { width: 15px; height: 15px; border: 2px solid var(--clr-dark); border-radius: 3px; }
.bg-curve { background: var(--clr-safe); }
.bg-point { background: var(--clr-danger); }
.bg-halflife { background: #ccc; }

@keyframes radAnim { 0% { opacity: 0; transform: translateY(20px); } 100% { opacity: 1; transform: translateY(0); } }

@media (max-width: 700px) {
    .radio-form-grid, .radio-result-grid { grid-template-columns: 1fr; }
}