:root {
    --brand: #2a5bd7;
    --brand-2: #1f3f8a;
    --brand-soft: #e9f0ff;
    --brand-ink: #0f1c3b;
    --bg: #f4f6fc;
    --bg-2: #eef2fb;
    --card: #ffffff;
    --text: #1b2340;
    --text-soft: #59658a;
    --text-mute: #8893b3;
    --line: #e4e8f5;
    --line-strong: #cbd2ea;
    --ok: #1f8a5a;
    --ok-soft: #e4f5ec;
    --warn: #b9770e;
    --warn-soft: #fff6df;
    --err: #c63c3c;
    --err-soft: #fdecec;
    --radius-sm: 8px;
    --radius: 14px;
    --radius-lg: 20px;
    --shadow-sm: 0 1px 2px rgba(22, 32, 72, 0.06), 0 1px 1px rgba(22, 32, 72, 0.04);
    --shadow: 0 10px 30px rgba(22, 32, 72, 0.08), 0 2px 6px rgba(22, 32, 72, 0.05);
    --shadow-lg: 0 30px 60px rgba(22, 32, 72, 0.14), 0 6px 16px rgba(22, 32, 72, 0.08);
}

*, *::before, *::after { box-sizing: border-box; }

html, body {
    margin: 0;
    padding: 0;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    text-rendering: optimizeLegibility;
}

body {
    font-family: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", -apple-system, BlinkMacSystemFont,
                 "Segoe UI", "Helvetica Neue", Arial, "Noto Sans CJK SC", sans-serif;
    color: var(--text);
    background: var(--bg);
    min-height: 100vh;
    line-height: 1.55;
}

.hidden { display: none !important; }

.page-shell {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* ------------------ Brand hero ------------------ */
.brand-hero {
    position: relative;
    overflow: hidden;
    background:
      radial-gradient(1200px 400px at 85% -10%, rgba(42,91,215,0.18), transparent 60%),
      radial-gradient(900px 360px at -10% 10%, rgba(31,63,138,0.16), transparent 60%),
      linear-gradient(180deg, #0f1c3b 0%, #132a66 60%, #1a3b91 100%);
    color: #eef3ff;
    padding: 44px 24px 72px;
}

.hero-grid {
    position: absolute; inset: 0;
    background-image:
      linear-gradient(rgba(255,255,255,0.06) 1px, transparent 1px),
      linear-gradient(90deg, rgba(255,255,255,0.06) 1px, transparent 1px);
    background-size: 36px 36px;
    mask-image: radial-gradient(ellipse at center, #000 40%, transparent 78%);
    -webkit-mask-image: radial-gradient(ellipse at center, #000 40%, transparent 78%);
    pointer-events: none;
}

.site-header {
    position: relative;
    max-width: 1080px;
    margin: 0 auto;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 24px;
}

.brand-mark {
    display: flex; align-items: center; gap: 14px;
}

.brand-icon {
    width: 48px; height: 48px;
    display: inline-flex; align-items: center; justify-content: center;
    color: #fff;
    background: linear-gradient(135deg, rgba(255,255,255,0.14), rgba(255,255,255,0.04));
    border: 1px solid rgba(255,255,255,0.18);
    border-radius: 14px;
    backdrop-filter: blur(10px);
}
.brand-icon svg { width: 28px; height: 28px; }

.brand-name {
    font-size: 1.6rem;
    font-weight: 700;
    letter-spacing: 0.5px;
    line-height: 1.1;
}
.brand-sub {
    font-weight: 500;
    font-size: 0.95rem;
    color: #b7c9ff;
    margin-left: 4px;
}
.brand-line {
    margin-top: 4px;
    font-size: 0.85rem;
    color: #a9bcf0;
    letter-spacing: 2px;
}

.hero-features {
    list-style: none;
    display: flex;
    gap: 12px;
    margin: 0;
    flex-wrap: wrap;
}
.hero-features li {
    display: inline-flex; align-items: center; gap: 8px;
    padding: 7px 12px;
    font-size: 0.85rem;
    color: #dbe5ff;
    background: rgba(255,255,255,0.06);
    border: 1px solid rgba(255,255,255,0.10);
    border-radius: 999px;
    backdrop-filter: blur(8px);
}
.chip-dot {
    width: 8px; height: 8px; border-radius: 999px; display: inline-block;
}
.chip-dot-1 { background: #66c2ff; box-shadow: 0 0 0 3px rgba(102,194,255,0.25); }
.chip-dot-2 { background: #7cf3c0; box-shadow: 0 0 0 3px rgba(124,243,192,0.25); }
.chip-dot-3 { background: #ffcf7a; box-shadow: 0 0 0 3px rgba(255,207,122,0.25); }

/* ------------------ Workspace ------------------ */
.workspace {
    max-width: 1080px;
    width: 100%;
    margin: -48px auto 0;
    padding: 0 24px 40px;
    display: flex;
    flex-direction: column;
    gap: 20px;
    position: relative;
}

.card {
    background: var(--card);
    border: 1px solid var(--line);
    border-radius: var(--radius-lg);
    padding: 26px 26px 22px;
    box-shadow: var(--shadow);
    animation: card-in 420ms cubic-bezier(.2,.7,.2,1) both;
}
@keyframes card-in {
    from { opacity: 0; transform: translateY(8px); }
    to   { opacity: 1; transform: translateY(0); }
}

.card-head { margin-bottom: 18px; }
.card-head h2 {
    margin: 0 0 6px;
    font-size: 1.1rem;
    display: inline-flex;
    align-items: center;
    gap: 10px;
    color: var(--brand-ink);
    letter-spacing: 0.2px;
}
.card-sub {
    margin: 0;
    color: var(--text-soft);
    font-size: 0.92rem;
}

.step-num {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 26px; height: 26px;
    font-size: 0.85rem;
    font-weight: 700;
    color: #fff;
    background: linear-gradient(135deg, var(--brand), var(--brand-2));
    border-radius: 8px;
    box-shadow: inset 0 -1px 0 rgba(0,0,0,0.15);
}

/* ------------------ Drop zone ------------------ */
.drop-zone {
    position: relative;
    border: 2px dashed var(--line-strong);
    border-radius: var(--radius);
    padding: 28px;
    text-align: center;
    cursor: pointer;
    background:
      radial-gradient(600px 120px at 50% 100%, rgba(42,91,215,0.07), transparent 65%),
      linear-gradient(180deg, #fbfcff, #f4f7ff);
    transition: transform 160ms ease, box-shadow 200ms ease, border-color 200ms ease, background-color 200ms ease;
    color: var(--text-soft);
    outline: none;
}
.drop-zone:hover {
    border-color: var(--brand);
    background:
      radial-gradient(600px 120px at 50% 100%, rgba(42,91,215,0.12), transparent 65%),
      linear-gradient(180deg, #fafcff, #eef4ff);
    box-shadow: var(--shadow-sm);
    transform: translateY(-1px);
}
.drop-zone.dragover {
    border-color: var(--brand);
    background:
      radial-gradient(600px 160px at 50% 100%, rgba(42,91,215,0.18), transparent 65%),
      linear-gradient(180deg, #eef4ff, #e1ecff);
    box-shadow: 0 0 0 4px rgba(42,91,215,0.12), var(--shadow-sm);
    animation: pulse 900ms ease-in-out infinite alternate;
}
@keyframes pulse {
    from { box-shadow: 0 0 0 4px rgba(42,91,215,0.10), var(--shadow-sm); }
    to   { box-shadow: 0 0 0 8px rgba(42,91,215,0.08), var(--shadow-sm); }
}
.drop-zone:focus-visible {
    border-color: var(--brand);
    box-shadow: 0 0 0 4px rgba(42,91,215,0.15), var(--shadow-sm);
}

.drop-inner {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 16px;
}
.drop-illus {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    color: var(--brand);
}
.illus-floater {
    width: 72px; height: 72px;
    display: inline-flex; align-items: center; justify-content: center;
    background: rgba(42,91,215,0.10);
    border-radius: 18px;
    animation: float 4s ease-in-out infinite;
}
.illus-floater svg { width: 56px; height: 56px; }
.illus-arrow {
    width: 32px; height: 32px;
    opacity: 0.9;
    animation: bob 1.5s ease-in-out infinite;
}
@keyframes float {
    0%, 100% { transform: translateY(0); }
    50%      { transform: translateY(-4px); }
}
@keyframes bob {
    0%, 100% { transform: translateY(0); opacity: 0.6; }
    50%      { transform: translateY(3px); opacity: 1; }
}

.drop-title {
    font-size: 1.15rem;
    font-weight: 600;
    color: var(--brand-ink);
}
.drop-sub {
    font-size: 0.92rem;
    color: var(--text-soft);
}
.drop-cta {
    color: var(--brand);
    font-weight: 600;
    text-decoration: underline;
    text-decoration-color: rgba(42,91,215,0.4);
    text-underline-offset: 3px;
}

/* ------------------ File list ------------------ */
.file-list {
    margin-top: 16px;
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
    gap: 10px;
}
.file-item {
    position: relative;
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 10px 12px 10px 12px;
    padding-left: 40px;
    background: linear-gradient(180deg, #fafbff, #f3f6fe);
    border: 1px solid var(--line);
    border-radius: var(--radius-sm);
    color: var(--text);
    font-size: 0.92rem;
    transition: transform 140ms ease, border-color 160ms ease, box-shadow 160ms ease;
    animation: item-in 260ms ease both;
}
@keyframes item-in {
    from { opacity: 0; transform: translateY(4px) scale(0.98); }
    to   { opacity: 1; transform: translateY(0) scale(1); }
}
.file-item:hover {
    transform: translateY(-1px);
    border-color: var(--line-strong);
    box-shadow: var(--shadow-sm);
}
.file-item::before {
    content: "";
    position: absolute;
    left: 12px; top: 50%;
    width: 20px; height: 22px;
    margin-top: -11px;
    border: 1.5px solid var(--brand);
    border-radius: 3px;
    background:
      linear-gradient(135deg, transparent 45%, var(--brand) 45% 55%, transparent 55%),
      var(--brand-soft);
}
.file-item::after {
    content: "DXF";
    position: absolute;
    left: 12px; top: 50%;
    margin-top: -1px;
    width: 20px;
    text-align: center;
    font-size: 0.58rem;
    font-weight: 700;
    color: var(--brand);
    letter-spacing: 0.3px;
}

.file-item .remove-btn {
    margin-left: auto;
    background: transparent;
    border: 1px solid transparent;
    color: var(--text-mute);
    cursor: pointer;
    width: 24px; height: 24px;
    border-radius: 6px;
    font-size: 1.05rem;
    line-height: 1;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    transition: background 140ms ease, color 140ms ease, border-color 140ms ease;
}
.file-item .remove-btn:hover {
    background: #fff1f1;
    color: var(--err);
    border-color: #f6d1d1;
}

/* ------------------ Config grid ------------------ */
.config-grid {
    display: grid;
    grid-template-columns: repeat(12, 1fr);
    gap: 14px 16px;
    align-items: end;
}
.field {
    grid-column: span 4;
    display: flex;
    flex-direction: column;
    gap: 8px;
}
.field-spacer { grid-column: span 3; }
.field-action { grid-column: span 1; justify-self: end; }
.grid-field { grid-column: span 2; }

.field label {
    font-size: 0.9rem;
    color: var(--text-soft);
    font-weight: 500;
}
.field .unit {
    color: var(--text-mute);
    font-size: 0.8rem;
    margin-left: 2px;
    font-weight: 400;
}

.field select,
.field .num-input {
    width: 100%;
    padding: 10px 12px;
    border: 1px solid var(--line-strong);
    border-radius: 10px;
    font-size: 0.95rem;
    font-family: inherit;
    background: #fff;
    color: var(--text);
    transition: border-color 150ms ease, box-shadow 150ms ease, background-color 150ms ease;
    outline: none;
}
.field select:hover, .field .num-input:hover {
    border-color: #b6c2e2;
    background: #fbfcff;
}
.field select:focus, .field .num-input:focus {
    border-color: var(--brand);
    box-shadow: 0 0 0 4px rgba(42,91,215,0.14);
    background: #fff;
}
.num-wrap { display: block; }

.sr-select { display: none !important; }

/* Segmented arrangement buttons */
.seg-group {
    display: inline-flex;
    padding: 4px;
    background: var(--bg-2);
    border: 1px solid var(--line);
    border-radius: 12px;
    gap: 2px;
    align-self: flex-start;
}
.seg-btn {
    --p: 0%;
    position: relative;
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 8px 12px;
    font: inherit;
    font-size: 0.88rem;
    color: var(--text-soft);
    background: transparent;
    border: none;
    border-radius: 9px;
    cursor: pointer;
    transition: color 160ms ease;
}
.seg-ico {
    width: 18px; height: 18px;
    display: inline-flex; align-items: center; justify-content: center;
    opacity: 0.85;
}
.seg-ico svg { width: 18px; height: 18px; }
.seg-btn:hover { color: var(--text); }
.seg-btn.is-active {
    color: #fff;
    background: linear-gradient(135deg, var(--brand), var(--brand-2));
    box-shadow: 0 4px 12px rgba(42,91,215,0.28), inset 0 -1px 0 rgba(0,0,0,0.15);
}
.seg-btn.is-active::after {
    content: "";
    position: absolute;
    left: 50%; bottom: -6px;
    width: 4px; height: 4px;
    margin-left: -2px;
    border-radius: 999px;
    background: var(--brand);
}
.seg-btn:focus-visible { outline: 2px solid rgba(42,91,215,0.5); outline-offset: 2px; }

/* ------------------ Buttons ------------------ */
.btn-primary {
    position: relative;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    min-height: 42px;
    padding: 0 22px;
    font: inherit;
    font-weight: 600;
    font-size: 0.98rem;
    color: #fff;
    background: linear-gradient(135deg, var(--brand) 0%, var(--brand-2) 100%);
    border: none;
    border-radius: 12px;
    cursor: pointer;
    box-shadow: 0 8px 20px rgba(42,91,215,0.28), inset 0 -1px 0 rgba(0,0,0,0.18);
    transition: transform 160ms cubic-bezier(.2,.7,.2,1), box-shadow 200ms ease, filter 200ms ease, opacity 200ms ease;
    white-space: nowrap;
}
.btn-primary:hover:not(:disabled) {
    transform: translateY(-1px);
    filter: brightness(1.03);
    box-shadow: 0 14px 28px rgba(42,91,215,0.32), inset 0 -1px 0 rgba(0,0,0,0.18);
}
.btn-primary:active:not(:disabled) { transform: translateY(0); }
.btn-primary:disabled {
    opacity: 0.55;
    cursor: not-allowed;
    filter: grayscale(0.2);
}
.btn-primary.is-loading .btn-label { opacity: 0.7; }
.btn-loader {
    width: 16px; height: 16px;
    border-radius: 999px;
    border: 2px solid rgba(255,255,255,0.4);
    border-top-color: #fff;
    animation: spin 700ms linear infinite;
    display: none;
}
.btn-primary.is-loading .btn-loader { display: inline-block; }
@keyframes spin { to { transform: rotate(360deg); } }

.btn-download {
    --t: var(--ok);
    display: inline-flex;
    align-items: center;
    gap: 10px;
    padding: 12px 22px;
    min-height: 44px;
    font-weight: 600;
    color: #fff;
    background: linear-gradient(135deg, #21a468, #158a54);
    border-radius: 12px;
    text-decoration: none;
    box-shadow: 0 8px 18px rgba(31,138,90,0.28), inset 0 -1px 0 rgba(0,0,0,0.18);
    transition: transform 160ms ease, box-shadow 200ms ease, filter 200ms ease;
}
.btn-download:hover { transform: translateY(-1px); filter: brightness(1.04); box-shadow: 0 14px 26px rgba(31,138,90,0.32); }
.btn-download:focus-visible { outline: 3px solid rgba(31,138,90,0.35); outline-offset: 2px; }
.btn-download .btn-ico { width: 18px; height: 18px; display: inline-flex; }
.btn-download .btn-ico svg { width: 18px; height: 18px; }

.btn-secondary {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    min-height: 44px;
    padding: 0 20px;
    font: inherit;
    font-weight: 600;
    color: var(--text);
    background: #fff;
    border: 1px solid var(--line-strong);
    border-radius: 12px;
    cursor: pointer;
    transition: transform 160ms ease, box-shadow 160ms ease, border-color 160ms ease, background-color 160ms ease;
}
.btn-secondary:hover {
    transform: translateY(-1px);
    background: #f8faff;
    border-color: #b6c2e2;
    box-shadow: var(--shadow-sm);
}
.btn-secondary:active { transform: translateY(0); }
.btn-secondary:focus-visible { outline: 3px solid rgba(42,91,215,0.22); outline-offset: 2px; }

/* ------------------ Capability note ------------------ */
.capability-note {
    margin: 16px 0 0;
    padding: 10px 14px;
    background: var(--warn-soft);
    border: 1px solid #f2dba0;
    border-radius: 10px;
    color: var(--warn);
    font-size: 0.88rem;
    line-height: 1.55;
    animation: note-in 260ms ease both;
}
@keyframes note-in {
    from { opacity: 0; transform: translateY(-3px); }
    to   { opacity: 1; transform: translateY(0); }
}

/* ------------------ Result card ------------------ */
.result-head {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
    flex-wrap: wrap;
    margin-bottom: 14px;
}
.result-title {
    color: var(--ok);
}
.success-dot {
    display: inline-block;
    width: 10px; height: 10px;
    border-radius: 999px;
    background: #28c07a;
    box-shadow: 0 0 0 4px rgba(40,192,122,0.20);
    animation: okpop 420ms cubic-bezier(.2,1.2,.3,1) both;
}
@keyframes okpop {
    0%   { transform: scale(0.2); opacity: 0; }
    60%  { transform: scale(1.25); opacity: 1; }
    100% { transform: scale(1); }
}

.result-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    align-items: center;
}
.meta-chip {
    display: inline-flex;
    align-items: center;
    padding: 5px 12px;
    font-size: 0.82rem;
    border-radius: 999px;
    border: 1px solid transparent;
    line-height: 1.4;
    animation: chip-in 380ms ease both;
}
@keyframes chip-in {
    from { opacity: 0; transform: translateY(2px); }
    to   { opacity: 1; transform: translateY(0); }
}
.meta-chip-neutral { background: var(--bg-2); border-color: var(--line); color: var(--text-soft); }
.meta-chip-info    { background: var(--brand-soft); border-color: #cfd9fb; color: var(--brand-2); }
.meta-chip-scale   { background: var(--ok-soft);  border-color: #bde5d1; color: var(--ok); }

.preview-shell {
    position: relative;
    padding: 14px;
    background:
      linear-gradient(135deg, #f6f8ff, #eef2fb);
    border: 1px solid var(--line);
    border-radius: var(--radius);
    overflow: hidden;
    margin-bottom: 18px;
}
.preview-shell::before {
    content: "";
    position: absolute;
    inset: 0;
    background-image:
      linear-gradient(rgba(22,32,72,0.03) 1px, transparent 1px),
      linear-gradient(90deg, rgba(22,32,72,0.03) 1px, transparent 1px);
    background-size: 24px 24px;
    pointer-events: none;
}
.preview-container img {
    max-width: 100%;
    height: auto;
    border-radius: 8px;
    box-shadow: var(--shadow-sm);
    position: relative;
    z-index: 1;
}
.viewer-container {
    position: relative;
    width: 100%;
    height: 520px;
    background: #ffffff;
    border-radius: 10px;
    overflow: hidden;
    box-shadow: var(--shadow-sm);
    z-index: 1;
}
.viewer-container canvas {
    display: block;
    width: 100%;
    height: 100%;
    touch-action: none;
}
.viewer-toolbar {
    position: absolute;
    top: 10px;
    left: 10px;
    right: 10px;
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
    z-index: 10;
}
.toolbar-btn {
    padding: 5px 12px;
    font: inherit;
    font-size: 0.82rem;
    border: 1px solid #d4daed;
    border-radius: 8px;
    background: rgba(255, 255, 255, 0.94);
    color: var(--text);
    cursor: pointer;
    backdrop-filter: blur(6px);
    transition: background 140ms ease, box-shadow 140ms ease, color 140ms ease, border-color 140ms ease, transform 140ms ease;
}
.toolbar-btn:hover {
    background: #eef2fb;
    border-color: #c1c8e1;
    box-shadow: 0 2px 6px rgba(22,32,72,0.10);
    transform: translateY(-1px);
}
.toolbar-btn-primary {
    background: linear-gradient(135deg, var(--brand), var(--brand-2));
    border-color: transparent;
    color: #fff;
    box-shadow: 0 4px 12px rgba(42,91,215,0.28);
}
.toolbar-btn-primary:hover {
    background: linear-gradient(135deg, var(--brand), var(--brand-2));
    filter: brightness(1.04);
    color: #fff;
    border-color: transparent;
}

.viewer-status {
    margin: 10px 0 0;
    color: var(--text-soft);
    font-size: 0.9rem;
    text-align: center;
}

.result-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    justify-content: center;
}

/* ------------------ Error ------------------ */
.error-card {
    display: flex;
    gap: 14px;
    align-items: flex-start;
}
.error-ico {
    width: 40px; height: 40px;
    display: inline-flex; align-items: center; justify-content: center;
    border-radius: 10px;
    background: var(--err-soft);
    color: var(--err);
    flex: 0 0 auto;
}
.error-ico svg { width: 24px; height: 24px; }
.error-card h3 {
    margin: 0 0 4px;
    font-size: 1.02rem;
    color: var(--err);
}
.error-card p {
    margin: 0;
    color: var(--text-soft);
    font-size: 0.94rem;
}

/* ------------------ Footer ------------------ */
.site-footer {
    max-width: 1080px;
    width: 100%;
    margin: 0 auto;
    padding: 0 24px 28px;
    color: var(--text-mute);
}
.footer-inner {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 10px;
    padding-top: 6px;
    border-top: 1px dashed var(--line);
    font-size: 0.85rem;
}
.footer-brand {
    color: var(--text-soft);
    font-weight: 600;
    letter-spacing: 0.4px;
}

/* ------------------ Responsive ------------------ */
@media (max-width: 860px) {
    .field            { grid-column: span 6; }
    .field-spacer     { grid-column: span 6; }
    .grid-field       { grid-column: span 3; }
    .field-action     { grid-column: 1 / -1; justify-self: stretch; }
    .field-action .btn-primary { width: 100%; }
    .hero-features    { display: none; }
}

@media (max-width: 620px) {
    .brand-hero         { padding: 28px 18px 56px; }
    .brand-name         { font-size: 1.3rem; }
    .brand-icon         { width: 42px; height: 42px; }
    .workspace          { padding: 0 16px 32px; }
    .card               { padding: 20px 16px; border-radius: 16px; }
    .drop-zone          { padding: 22px 14px; }
    .config-grid        { grid-template-columns: 1fr; }
    .field, .field-spacer, .grid-field, .field-action { grid-column: 1 / -1; }
    .result-head        { align-items: flex-start; }
    .viewer-container   { height: 380px; }
    .result-actions .btn-download, .result-actions .btn-secondary { width: 100%; justify-content: center; }
}

@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: 0.001ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.001ms !important;
    }
}