:root {
    --bg: #090d0f;
    --surface: #101619;
    --surface-2: #151d21;
    --surface-3: #1b262b;
    --field: #06090b;
    --line: #33434b;
    --line-soft: rgba(223, 239, 242, 0.10);
    --text: #edf7f6;
    --muted: #a9bbbd;
    --subtle: #71858a;
    --green: #35d99b;
    --green-dark: #0d3028;
    --amber: #f2b84b;
    --amber-dark: #2d2412;
    --red: #ef626c;
    --blue: #7ab7ff;
    --cyan: #6ee7f9;
    --shadow: 0 20px 60px rgba(0, 0, 0, 0.46);
    --inner-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.055);
    --mono: "IBM Plex Mono", "SFMono-Regular", Consolas, "Liberation Mono", monospace;
    --sans: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

* {
    box-sizing: border-box;
}

html {
    min-height: 100%;
}

body {
    margin: 0;
    min-height: 100vh;
    background:
        linear-gradient(rgba(255, 255, 255, 0.018) 1px, transparent 1px),
        linear-gradient(90deg, rgba(255, 255, 255, 0.015) 1px, transparent 1px),
        radial-gradient(circle at 50% 0%, rgba(53, 217, 155, 0.075), transparent 34rem),
        linear-gradient(180deg, #11191c 0%, #070a0b 100%);
    background-size: 44px 44px, 44px 44px, auto, auto;
    color: var(--text);
    font-family: var(--sans);
    line-height: 1.45;
    padding: max(18px, env(safe-area-inset-top)) 18px max(18px, env(safe-area-inset-bottom));
}

button,
input,
select {
    font: inherit;
}

button {
    color: inherit;
}

.app-shell {
    width: min(1440px, 100%);
    margin: 0 auto;
}

.header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 20px;
    min-height: 98px;
    padding: 14px 18px;
    margin-bottom: 16px;
    border: 1px solid var(--line-soft);
    border-radius: 8px;
    background:
        linear-gradient(135deg, rgba(255, 255, 255, 0.055), rgba(255, 255, 255, 0.015)),
        rgba(16, 22, 25, 0.94);
    box-shadow: var(--shadow);
    backdrop-filter: blur(14px);
    position: relative;
    overflow: hidden;
}

.header::after {
    content: "";
    position: absolute;
    inset: auto 18px 0;
    height: 1px;
    background: linear-gradient(90deg, transparent, rgba(53, 217, 155, 0.6), transparent);
}

.brand {
    display: flex;
    align-items: center;
    gap: 16px;
    min-width: 0;
}

.main-logo {
    width: 70px;
    height: 70px;
    object-fit: contain;
    border-radius: 8px;
    border: 1px solid rgba(255, 255, 255, 0.10);
    background: #050607;
    flex: 0 0 auto;
}

.header h1 {
    margin: 0;
    font-size: clamp(1.38rem, 2.45vw, 2.25rem);
    line-height: 1.05;
    letter-spacing: 0;
    font-weight: 850;
}

.header p {
    margin: 8px 0 0;
    color: var(--muted);
    max-width: 780px;
    font-size: clamp(0.95rem, 1.4vw, 1.05rem);
}

.install-btn,
.category-btn,
.tool-btn {
    border: 1px solid var(--line);
    background: var(--surface-2);
    border-radius: 6px;
    cursor: pointer;
    transition: border-color 0.14s ease, background 0.14s ease, color 0.14s ease;
}

.install-btn {
    min-height: 42px;
    padding: 0 18px;
    color: #04120d;
    background: linear-gradient(180deg, #69e8b2, var(--green));
    border-color: rgba(52, 211, 153, 0.88);
    font-weight: 850;
    white-space: nowrap;
}

.install-btn:hover,
.category-btn:hover,
.tool-btn:hover {
    border-color: var(--green);
}

.calculator {
    display: grid;
    grid-template-columns: minmax(310px, 390px) minmax(0, 1fr);
    gap: 16px;
    align-items: start;
}

.controls,
.workspace,
.reference-strip {
    background:
        linear-gradient(180deg, rgba(255, 255, 255, 0.025), transparent 210px),
        rgba(16, 22, 25, 0.94);
    border: 1px solid var(--line-soft);
    box-shadow: var(--shadow);
    backdrop-filter: blur(12px);
}

.controls,
.workspace {
    border-radius: 8px;
}

.controls {
    overflow: hidden;
}

.control-panel {
    padding: 16px 18px 18px;
    border-bottom: 1px solid var(--line-soft);
}

.control-panel:last-child {
    border-bottom: 0;
}

.control-panel h2,
.eyebrow,
.label {
    font-family: var(--mono);
}

.control-panel h2 {
    display: flex;
    align-items: center;
    gap: 8px;
    margin: 0 0 13px;
    font-size: 0.78rem;
    text-transform: uppercase;
    color: var(--amber);
    letter-spacing: 0;
}

.control-panel h2::before {
    content: "";
    width: 8px;
    height: 8px;
    border-radius: 2px;
    background: var(--amber);
    box-shadow: 0 0 0 3px rgba(243, 179, 61, 0.12);
}

label {
    display: block;
    margin: 13px 0 7px;
    color: var(--muted);
    font-size: 0.82rem;
    font-weight: 800;
}

input,
select {
    width: 100%;
    min-height: 44px;
    color: var(--text);
    background:
        linear-gradient(180deg, rgba(255, 255, 255, 0.025), transparent),
        var(--field);
    border: 1px solid var(--line);
    border-radius: 6px;
    padding: 10px 12px;
    box-shadow: var(--inner-shadow);
}

input {
    font-family: var(--mono);
}

select {
    appearance: auto;
}

input:focus,
select:focus {
    outline: 2px solid rgba(52, 211, 153, 0.23);
    border-color: var(--green);
}

.two-col {
    display: grid;
    grid-template-columns: minmax(0, 1fr) 0.76fr;
    gap: 12px;
}

.band-badge {
    margin-top: 10px;
    min-height: 38px;
    padding: 8px 10px;
    border-radius: 6px;
    font-family: var(--mono);
    font-size: 0.82rem;
    font-weight: 850;
    text-align: center;
}

.band-badge.valid {
    color: var(--green);
    background:
        linear-gradient(180deg, rgba(53, 217, 155, 0.13), transparent),
        var(--green-dark);
    border: 1px solid rgba(52, 211, 153, 0.46);
}

.band-badge.invalid {
    color: #ff9aa2;
    background: rgba(239, 98, 108, 0.12);
    border: 1px solid rgba(239, 98, 108, 0.42);
}

.unit-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    min-height: 48px;
    margin-top: 18px;
    padding: 10px 12px;
    border-radius: 6px;
    background:
        linear-gradient(180deg, rgba(255, 255, 255, 0.025), transparent),
        var(--field);
    border: 1px solid rgba(255, 255, 255, 0.05);
    color: var(--muted);
    font-family: var(--mono);
    font-weight: 850;
}

.switch {
    width: 50px;
    height: 26px;
    position: relative;
    flex: 0 0 auto;
}

.switch input {
    opacity: 0;
    width: 0;
    height: 0;
}

.slider {
    position: absolute;
    inset: 0;
    border-radius: 999px;
    background: #24343a;
    border: 1px solid var(--line);
}

.slider::before {
    content: "";
    position: absolute;
    width: 18px;
    height: 18px;
    left: 3px;
    top: 3px;
    border-radius: 50%;
    background: #b7c7ca;
    transition: transform 0.16s ease, background 0.16s ease;
}

input:checked + .slider::before {
    transform: translateX(24px);
    background: var(--amber);
}

.category-tabs {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 8px;
}

.category-btn {
    min-height: 42px;
    padding: 8px 10px;
    color: var(--muted);
    font-weight: 850;
    box-shadow: var(--inner-shadow);
}

.category-btn.active,
.tool-btn.active {
    color: #06100d;
    background: linear-gradient(180deg, #61e6ae, var(--green));
    border-color: var(--green);
}

.tool-list {
    display: grid;
    gap: 8px;
    max-height: 468px;
    overflow: auto;
    padding-right: 3px;
    scrollbar-width: thin;
    scrollbar-color: var(--line) transparent;
}

.tool-btn {
    display: flex;
    justify-content: space-between;
    gap: 12px;
    align-items: center;
    min-height: 48px;
    padding: 10px 12px;
    text-align: left;
    color: var(--text);
    box-shadow: var(--inner-shadow);
}

.tool-btn span {
    overflow-wrap: anywhere;
}

.tool-btn small {
    color: currentColor;
    opacity: 0.7;
    white-space: nowrap;
    font-family: var(--mono);
    font-size: 0.72rem;
}

.workspace {
    min-width: 0;
    overflow: hidden;
}

.workspace-head {
    display: flex;
    justify-content: space-between;
    gap: 16px;
    align-items: start;
    padding: clamp(18px, 2.3vw, 28px) clamp(18px, 2.6vw, 32px);
    border-bottom: 1px solid var(--line-soft);
    background:
        linear-gradient(180deg, rgba(255, 255, 255, 0.045), transparent),
        linear-gradient(90deg, rgba(53, 217, 155, 0.045), transparent 52%);
}

.eyebrow {
    margin: 0 0 7px;
    color: var(--amber);
    font-size: 0.78rem;
    text-transform: uppercase;
    font-weight: 850;
}

.workspace h2 {
    margin: 0;
    font-size: clamp(1.48rem, 2.55vw, 2.25rem);
    line-height: 1.1;
    letter-spacing: 0;
}

.type-pill {
    display: inline-flex;
    align-items: center;
    min-height: 32px;
    border: 1px solid rgba(122, 183, 255, 0.42);
    color: #add2ff;
    background: rgba(122, 183, 255, 0.10);
    border-radius: 6px;
    padding: 0 12px;
    font-family: var(--mono);
    font-size: 0.82rem;
    font-weight: 850;
    white-space: nowrap;
}

.tool-visual {
    height: clamp(172px, 24vw, 260px);
    margin: clamp(18px, 2.6vw, 32px) clamp(18px, 2.6vw, 32px) 0;
    border: 1px solid var(--line-soft);
    background:
        linear-gradient(rgba(110, 231, 249, 0.055) 1px, transparent 1px),
        linear-gradient(90deg, rgba(110, 231, 249, 0.045) 1px, transparent 1px),
        linear-gradient(rgba(110, 231, 249, 0.075) 1px, transparent 1px),
        linear-gradient(90deg, rgba(110, 231, 249, 0.06) 1px, transparent 1px),
        radial-gradient(circle at 50% 40%, rgba(53, 217, 155, 0.09), transparent 58%),
        #060b0d;
    background-size: 24px 24px, 24px 24px, 96px 96px, 96px 96px, auto, auto;
    border-radius: 8px;
    overflow: hidden;
    box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.055), inset 0 0 60px rgba(0, 0, 0, 0.35);
    position: relative;
}

.tool-visual::after {
    content: "";
    position: absolute;
    inset: 12px;
    border: 1px solid rgba(110, 231, 249, 0.08);
    pointer-events: none;
}

.tool-visual svg {
    width: 100%;
    height: 100%;
    position: relative;
    z-index: 1;
}

.tool-visual line,
.tool-visual path,
.tool-visual rect,
.tool-visual circle {
    fill: none;
    stroke: #38dca0;
    stroke-width: 4.2;
    stroke-linecap: round;
    stroke-linejoin: round;
}

.tool-visual circle {
    fill: var(--amber);
    stroke: var(--amber);
    filter: none;
}

.tool-visual .secondary,
.tool-visual .feed {
    stroke: var(--amber);
}

.tool-visual .spacer {
    stroke: var(--subtle);
    stroke-width: 3.2;
    filter: none;
}

.tool-visual .hole {
    fill: var(--field);
    stroke: var(--amber);
    stroke-width: 3.6;
    filter: none;
}

.result-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(208px, 1fr));
    gap: 12px;
    padding: clamp(18px, 2.6vw, 32px);
}

.result-item {
    min-height: 108px;
    background:
        linear-gradient(180deg, rgba(255, 255, 255, 0.028), transparent),
        var(--field);
    border: 1px solid var(--line-soft);
    border-left: 3px solid rgba(52, 211, 153, 0.78);
    border-radius: 6px;
    padding: 15px 16px;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    gap: 12px;
    box-shadow: var(--inner-shadow);
}

.label {
    color: var(--muted);
    font-size: 0.75rem;
    text-transform: uppercase;
    font-weight: 850;
}

.value {
    color: #49e6a7;
    font-family: var(--mono);
    font-size: clamp(1.08rem, 1.8vw, 1.42rem);
    line-height: 1.16;
    font-weight: 850;
    overflow-wrap: anywhere;
}

.value.long-value {
    font-size: clamp(0.86rem, 1.2vw, 1.04rem);
    line-height: 1.35;
}

.notes-panel {
    margin: 0 clamp(18px, 2.6vw, 32px) clamp(18px, 2.6vw, 32px);
    padding: 16px 18px;
    border-radius: 6px;
    background:
        linear-gradient(180deg, rgba(242, 184, 75, 0.10), transparent),
        rgba(45, 36, 18, 0.84);
    border: 1px solid rgba(243, 179, 61, 0.30);
    box-shadow: var(--inner-shadow);
}

.notes-panel h3 {
    margin: 0 0 8px;
    font-family: var(--mono);
    font-size: 0.88rem;
    color: var(--amber);
    text-transform: uppercase;
}

.notes-panel p {
    margin: 8px 0 0;
    color: #f7ebd5;
}

.reference-strip {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1px;
    margin-top: 14px;
    border-radius: 8px;
    overflow: hidden;
}

.reference-strip div {
    padding: 16px 18px;
    background:
        linear-gradient(180deg, rgba(255, 255, 255, 0.025), transparent),
        rgba(8, 11, 12, 0.72);
}

.reference-strip strong,
.reference-strip span {
    display: block;
}

.reference-strip strong {
    margin-bottom: 5px;
    color: var(--amber);
    font-size: 0.92rem;
}

.reference-strip span {
    color: var(--muted);
    font-size: 0.92rem;
}

@media (max-width: 1040px) {
    .calculator {
        grid-template-columns: 320px minmax(0, 1fr);
    }
}

@media (max-width: 840px) {
    body {
        padding: 12px;
    }

    .header {
        align-items: flex-start;
        flex-direction: column;
        min-height: 0;
        padding: 14px;
    }

    .brand {
        align-items: flex-start;
    }

    .main-logo {
        width: 58px;
        height: 58px;
    }

    .install-btn {
        width: 100%;
    }

    .calculator {
        grid-template-columns: 1fr;
    }

    .controls {
        box-shadow: none;
    }

    .tool-list {
        max-height: none;
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }

    .reference-strip {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 560px) {
    .two-col,
    .category-tabs,
    .tool-list,
    .result-grid {
        grid-template-columns: 1fr;
    }

    .workspace-head {
        flex-direction: column;
        padding: 18px;
    }

    .tool-visual,
    .notes-panel {
        margin-right: 18px;
        margin-left: 18px;
    }

    .result-grid {
        padding: 18px;
    }

    .tool-btn {
        min-height: 46px;
    }
}


/* Formula panel (KaTeX) */
.formula-panel {
    margin: 0 clamp(18px, 2.6vw, 32px);
    padding: 10px 18px;
    border-radius: 6px;
    background:
        linear-gradient(180deg, rgba(122, 183, 255, 0.07), transparent),
        var(--field);
    border: 1px solid var(--line-soft);
    border-left: 3px solid rgba(122, 183, 255, 0.65);
    overflow-x: auto;
}

.formula-panel .katex-display {
    margin: 8px 0;
}

/* Analytical radiation pattern metrics */
.pattern-panel {
    margin: 0 clamp(18px, 2.6vw, 32px) clamp(18px, 2.6vw, 32px);
    padding: 16px 18px;
    border-radius: 6px;
    background:
        linear-gradient(180deg, rgba(110, 231, 249, 0.07), transparent),
        rgba(13, 33, 38, 0.84);
    border: 1px solid rgba(110, 231, 249, 0.28);
    box-shadow: var(--inner-shadow);
}

.pattern-panel h3 {
    margin: 0 0 12px;
    font-family: var(--mono);
    font-size: 0.88rem;
    color: var(--cyan);
    text-transform: uppercase;
}

.pattern-metrics {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
    gap: 10px;
}

.pattern-metric {
    background: var(--field);
    border: 1px solid var(--line-soft);
    border-radius: 6px;
    padding: 10px 12px;
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.pattern-metric .label {
    font-family: var(--mono);
    font-size: 0.72rem;
    text-transform: uppercase;
    color: var(--subtle);
}

.pattern-metric .value {
    font-family: var(--mono);
    font-size: 1.05rem;
    font-weight: 700;
    color: var(--cyan);
}

.pattern-note {
    margin: 12px 0 0;
    color: var(--muted);
    font-size: 0.92rem;
}

@media (max-width: 840px) {
    .formula-panel,
    .pattern-panel {
        margin-right: 18px;
        margin-left: 18px;
    }
}


.pattern-plot {
    margin-top: 12px;
    border-radius: 6px;
    background: var(--field);
    border: 1px solid var(--line-soft);
    overflow: hidden;
    min-height: 40px;
}

.pattern-plot:empty {
    display: none;
}


/* Full-wave simulation panel */
.sim-actions {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 12px;
    flex-wrap: wrap;
}

.sim-run-btn {
    font-family: var(--mono);
    font-size: 0.86rem;
    font-weight: 800;
    padding: 10px 18px;
    border-radius: 6px;
    border: 1px solid rgba(110, 231, 249, 0.45);
    background:
        linear-gradient(180deg, rgba(110, 231, 249, 0.16), transparent),
        var(--field);
    color: var(--cyan);
    cursor: pointer;
}

.sim-run-btn:hover:not(:disabled) {
    border-color: rgba(110, 231, 249, 0.8);
}

.sim-run-btn:disabled {
    opacity: 0.55;
    cursor: wait;
}

.sim-status {
    font-size: 0.88rem;
    color: var(--muted);
}