:root {
    --ink: #17213a;
    --muted: #68738a;
    --soft: #f4f6fb;
    --paper: #ffffff;
    --line: #dfe3ee;
    --accent: #635bdb;
    --accent-dark: #4b43b5;
    --accent-soft: #efeeff;
    --warm: #e08a3e;
    --danger: #c44252;
    --danger-soft: #fff0f3;
    --shadow: 0 18px 45px rgba(24, 33, 43, .07);
    --radius: 18px;
}

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

body {
    font-family: "DM Sans", system-ui, sans-serif;
    color: var(--ink);
    background:
        radial-gradient(circle at 82% 0%, rgba(99,91,219,.10), transparent 28rem),
        radial-gradient(circle at 5% 55%, rgba(49,164,196,.06), transparent 24rem),
        #f4f6fb;
    min-height: 100vh;
    line-height: 1.5;
}

.topbar {
    height: 76px;
    padding: 0 5vw;
    background: rgba(255,255,255,.94);
    border-bottom: 1px solid var(--line);
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.brand {
    color: var(--ink);
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: 12px;
}

.brand-mark {
    width: 38px;
    height: 38px;
    border-radius: 11px;
    display: grid;
    place-items: center;
    background: #17213a;
    color: white;
    font-size: 22px;
    font-weight: 600;
}

.brand strong {
    display: block;
    font-size: 16px;
    letter-spacing: -.02em;
}

.brand small {
    display: block;
    color: var(--muted);
    font-size: 11px;
}

.topbar-right {
    display: flex;
    align-items: center;
    gap: 14px;
    color: var(--muted);
    font-size: 12px;
}

.server-status,
.version {
    padding: 7px 10px;
    border: 1px solid var(--line);
    border-radius: 999px;
    background: white;
}

.server-status {
    display: flex;
    align-items: center;
    gap: 7px;
}

.status-dot {
    width: 7px;
    height: 7px;
    border-radius: 50%;
    background: var(--accent);
}

.version {
    font-family: "JetBrains Mono", monospace;
}

.page {
    width: min(1380px, 92vw);
    margin: 0 auto;
    padding: 54px 0 30px;
}

.hero {
    display: flex;
    align-items: flex-end;
    justify-content: space-between;
    gap: 40px;
    margin-bottom: 38px;
}

.eyebrow,
.panel-kicker {
    color: var(--accent);
    font-size: 10px;
    font-weight: 700;
    letter-spacing: .15em;
}

.hero h1 {
    margin-top: 10px;
    font-size: clamp(32px, 4vw, 54px);
    line-height: 1.05;
    letter-spacing: -.045em;
    font-weight: 700;
}

.hero h1 span {
    color: var(--accent);
}

.hero-text {
    max-width: 640px;
    margin-top: 17px;
    color: var(--muted);
    font-size: 15px;
}

.equation-card {
    min-width: 320px;
    padding: 24px 26px;
    background: var(--ink);
    color: white;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
}

.equation-label {
    display: block;
    color: #aab3c4;
    font-size: 9px;
    letter-spacing: .18em;
    font-weight: 700;
    margin-bottom: 10px;
}

.equation {
    font-family: "JetBrains Mono", monospace;
    font-size: 15px;
    white-space: nowrap;
}

.equation-note {
    display: block;
    margin-top: 9px;
    color: #b7bfcd;
    font-size: 11px;
}

.alert {
    margin-bottom: 22px;
    padding: 13px 16px;
    border-radius: 12px;
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 13px;
}

.alert.error {
    color: var(--danger);
    background: var(--danger-soft);
    border: 1px solid #f0cccc;
}

.alert-icon {
    width: 22px;
    height: 22px;
    border-radius: 50%;
    display: grid;
    place-items: center;
    background: var(--danger);
    color: white;
    font-weight: 700;
}

.workspace {
    display: grid;
    grid-template-columns: 390px 1fr;
    gap: 22px;
    align-items: start;
}

.control-panel,
.results-panel,
.comparison-card {
    background: var(--paper);
    border: 1px solid var(--line);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
}

.control-panel {
    padding: 27px;
}

.panel-heading,
.results-header {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    gap: 20px;
}

.panel-heading h2,
.results-header h2,
.comparison-card h2 {
    margin-top: 3px;
    font-size: 21px;
    letter-spacing: -.025em;
}

.panel-number {
    font-family: "JetBrains Mono", monospace;
    color: #a0abb2;
    font-size: 11px;
}

.field-section {
    margin-top: 26px;
}

.field-label {
    display: block;
    font-size: 12px;
    font-weight: 700;
    margin-bottom: 11px;
}

.method-list {
    display: grid;
    gap: 8px;
}

.method-option {
    cursor: pointer;
}

.method-option input {
    position: absolute;
    opacity: 0;
    pointer-events: none;
}

.method-box {
    min-height: 59px;
    padding: 9px 12px;
    border: 1px solid var(--line);
    border-radius: 12px;
    display: flex;
    align-items: center;
    gap: 11px;
    transition: .2s ease;
}

.method-box:hover {
    border-color: #c5c1f3;
    background: #fbfdfc;
}

.method-option input:checked + .method-box {
    border-color: var(--accent);
    background: var(--accent-soft);
}

.method-icon {
    width: 35px;
    height: 35px;
    border-radius: 9px;
    display: grid;
    place-items: center;
    background: white;
    color: var(--accent);
    font-family: "JetBrains Mono", monospace;
    font-weight: 700;
    border: 1px solid #dedcff;
}

.method-info {
    flex: 1;
}

.method-info strong,
.method-info small {
    display: block;
}

.method-info strong {
    font-size: 12px;
}

.method-info small {
    color: var(--muted);
    font-size: 10px;
    margin-top: 2px;
}

.radio-indicator {
    width: 15px;
    height: 15px;
    border: 1.5px solid #bdc7cc;
    border-radius: 50%;
    position: relative;
}

.method-option input:checked + .method-box .radio-indicator {
    border-color: var(--accent);
}

.method-option input:checked + .method-box .radio-indicator::after {
    content: "";
    position: absolute;
    inset: 3px;
    border-radius: 50%;
    background: var(--accent);
}

.separator {
    height: 1px;
    background: var(--line);
    margin: 26px 0;
}

.section-title-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.unit-hint {
    color: #9aa5ab;
    font-size: 9px;
    text-transform: uppercase;
    letter-spacing: .1em;
}

.params-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 12px;
}

.input-field.wide {
    grid-column: 1 / -1;
}

.input-field label {
    display: flex;
    align-items: baseline;
    justify-content: space-between;
    margin-bottom: 5px;
    font-size: 11px;
    font-weight: 700;
}

.input-field label span {
    color: #9aa5ab;
    font-weight: 400;
    font-size: 9px;
}

.input-field input {
    width: 100%;
    border: 1px solid var(--line);
    background: #fafbfb;
    border-radius: 9px;
    padding: 10px 11px;
    font: 500 12px "JetBrains Mono", monospace;
    color: var(--ink);
    outline: none;
    transition: .2s;
}

.input-field input:focus {
    background: white;
    border-color: var(--accent);
    box-shadow: 0 0 0 3px rgba(99,91,219,.12);
}

.run-button {
    width: 100%;
    margin-top: 25px;
    border: 0;
    border-radius: 11px;
    padding: 13px 15px;
    background: var(--ink);
    color: white;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 10px;
    justify-content: center;
    font: 700 12px "DM Sans", sans-serif;
    transition: .2s;
}

.run-button:hover {
    background: var(--accent-dark);
    transform: translateY(-1px);
}

.run-button .play {
    font-size: 10px;
}

.run-button .arrow {
    margin-left: auto;
    font-size: 16px;
}

.results-panel {
    padding: 27px;
    min-height: 600px;
}

.result-tag {
    padding: 6px 10px;
    border-radius: 999px;
    color: var(--accent);
    background: var(--accent-soft);
    font-size: 9px;
    font-weight: 800;
    letter-spacing: .08em;
}

.plot-frame {
    margin-top: 25px;
    border: 1px solid var(--line);
    border-radius: 13px;
    overflow: hidden;
    background: #fafbfb;
}

.plot-toolbar {
    height: 38px;
    padding: 0 13px;
    border-bottom: 1px solid var(--line);
    background: white;
    display: flex;
    justify-content: space-between;
    align-items: center;
    color: var(--muted);
    font-size: 10px;
}

.plot-toolbar span:first-child {
    display: flex;
    align-items: center;
    gap: 7px;
}

.plot-toolbar i {
    width: 7px;
    height: 7px;
    border-radius: 50%;
    background: var(--accent);
}

.plot-note {
    font-family: "JetBrains Mono", monospace;
    color: #9aa5ab;
}

.plot-area {
    min-height: 460px;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 16px;
    overflow-x: auto;      /* ajouté : permet le scroll si l'image reste large */
}

.plot-area img {
    display: block;
    max-width: 100%;
    height: auto;
    object-fit: contain;
    /* max-height: 510px;  <- supprimé : bloquait les graphiques multi-panneaux */
}

.empty-state {
    min-height: 460px;
    margin-top: 25px;
    border: 1px dashed #cdd6da;
    border-radius: 13px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    text-align: center;
    color: var(--muted);
}

.empty-visual {
    height: 65px;
    display: flex;
    align-items: center;
    gap: 3px;
    color: var(--accent);
    font-family: Georgia, serif;
    font-size: 34px;
    transform: rotate(-4deg);
    opacity: .7;
}

.empty-visual span:nth-child(2) {
    transform: translateY(-11px);
}

.empty-visual span:nth-child(3) {
    transform: translateY(-4px);
}

.empty-state h3 {
    color: var(--ink);
    margin-top: 8px;
    font-size: 15px;
}

.empty-state p {
    margin-top: 6px;
    font-size: 11px;
}

.empty-state strong {
    color: var(--accent);
}

.metrics {
    margin-top: 17px;
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    border: 1px solid var(--line);
    border-radius: 12px;
    overflow: hidden;
}

.metric {
    padding: 13px 14px;
    border-right: 1px solid var(--line);
    background: white;
}

.metric:last-child {
    border-right: 0;
}

.metric-label {
    display: block;
    color: #929da4;
    font-size: 8px;
    letter-spacing: .11em;
    font-weight: 800;
}

.metric strong {
    font-family: "JetBrains Mono", monospace;
    font-size: 15px;
    margin-top: 3px;
    display: inline-block;
}

.metric small {
    color: var(--muted);
    font-size: 9px;
    margin-left: 4px;
}

.comparison-card {
    margin-top: 22px;
    padding: 25px 27px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 30px;
}

.comparison-card p:not(.panel-kicker) {
    color: var(--muted);
    font-size: 11px;
    max-width: 520px;
    margin-top: 7px;
}

.comparison-steps {
    display: flex;
    align-items: center;
    gap: 13px;
}

.comparison-steps > div:not(.line) {
    display: grid;
    grid-template-columns: 28px auto;
    column-gap: 8px;
    align-items: center;
}

.comparison-steps span {
    grid-row: span 2;
    width: 28px;
    height: 28px;
    border-radius: 8px;
    display: grid;
    place-items: center;
    background: var(--accent-soft);
    color: var(--accent);
    font: 700 9px "JetBrains Mono", monospace;
}

.comparison-steps strong {
    font-size: 10px;
}

.comparison-steps small {
    color: var(--muted);
    font-size: 9px;
}

.comparison-steps .line {
    width: 30px;
    height: 1px;
    background: var(--line);
}

footer {
    width: min(1380px, 92vw);
    margin: 0 auto;
    padding: 20px 0 28px;
    display: flex;
    justify-content: space-between;
    color: #89949b;
    font-size: 10px;
}

@media (max-width: 1050px) {
    .workspace {
        grid-template-columns: 1fr;
    }

    .control-panel {
        order: 1;
    }

    .results-panel {
        order: 2;
    }

    .hero {
        align-items: stretch;
        flex-direction: column;
    }

    .equation-card {
        min-width: 0;
    }

    .comparison-card {
        flex-direction: column;
        align-items: flex-start;
    }
}

@media (max-width: 650px) {
    .page {
        padding-top: 32px;
    }

    .topbar {
        padding: 0 4vw;
    }

    .topbar-right .version {
        display: none;
    }

    .server-status {
        font-size: 10px;
    }

    .hero h1 {
        font-size: 34px;
    }

    .equation-card {
        overflow-x: auto;
    }

    .workspace,
    .control-panel,
    .results-panel {
        border-radius: 14px;
    }

    .control-panel,
    .results-panel {
        padding: 19px;
    }

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

    .input-field.wide {
        grid-column: auto;
    }

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

    .metric:nth-child(2) {
        border-right: 0;
    }

    .metric:nth-child(-n+2) {
        border-bottom: 1px solid var(--line);
    }

    .comparison-steps {
        width: 100%;
        justify-content: space-between;
        gap: 6px;
    }

    .comparison-steps .line {
        width: 12px;
    }

    footer {
        flex-direction: column;
        gap: 5px;
    }
}

.plot-area {
    overflow: hidden;
    cursor: grab;
    touch-action: none;
}

.plot-area.grabbing {
    cursor: grabbing;
}

.plot-area img {
    transform-origin: 0 0;
    will-change: transform;
    user-select: none;
    -webkit-user-drag: none;
}

.plot-toolbar {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 8px;
}

.zoom-hint {
    font-size: 0.8rem;
    color: var(--text-secondary, #64748B);
}