:root {
    --bg: #eef2ef;
    --surface: #fbfaf6;
    --surface-strong: #ffffff;
    --ink: #17201d;
    --muted: #68716d;
    --line: #d9dfda;
    --line-strong: #c4ccc6;
    --primary: #0e6f63;
    --primary-dark: #094f47;
    --accent: #b8753d;
    --accent-soft: #fff0df;
    --success: #1f7a53;
    --sidebar: #1d2724;
    --sidebar-soft: #26332f;
    --sidebar-line: rgba(255, 255, 255, 0.12);
    --shadow: 0 24px 70px rgba(29, 39, 36, 0.16);
    --shadow-soft: 0 14px 34px rgba(29, 39, 36, 0.1);
}

* {
    box-sizing: border-box;
}

body {
    min-height: 100vh;
    margin: 0;
    background:
        linear-gradient(180deg, #eef2ef 0%, #f7f4ee 100%);
    color: var(--ink);
    font-family: Inter, "Segoe UI", Arial, Helvetica, sans-serif;
}

button,
input {
    font: inherit;
}

button {
    -webkit-tap-highlight-color: transparent;
}

.app-shell {
    display: grid;
    grid-template-columns: 292px minmax(0, 1fr);
    gap: 22px;
    width: min(1200px, calc(100% - 32px));
    min-height: calc(100vh - 32px);
    margin: 16px auto;
}

.sidebar,
.content {
    border-radius: 8px;
    box-shadow: var(--shadow);
}

.sidebar {
    display: flex;
    flex-direction: column;
    gap: 26px;
    border: 1px solid rgba(255, 255, 255, 0.08);
    background:
        linear-gradient(180deg, rgba(255, 255, 255, 0.05), rgba(255, 255, 255, 0)),
        var(--sidebar);
    color: white;
    padding: 22px;
}

.content {
    position: relative;
    min-height: 620px;
    border: 1px solid rgba(255, 255, 255, 0.72);
    background: rgba(251, 250, 246, 0.9);
    padding: 30px;
}

.brand {
    display: flex;
    align-items: center;
    gap: 13px;
    border-bottom: 1px solid var(--sidebar-line);
    padding-bottom: 20px;
}

.brand-mark {
    display: grid;
    place-items: center;
    width: 54px;
    height: 54px;
    border: 1px solid rgba(255, 255, 255, 0.16);
    border-radius: 8px;
    background:
        linear-gradient(135deg, rgba(184, 117, 61, 0.9), rgba(14, 111, 99, 0.92));
    color: white;
    font-weight: 900;
    box-shadow: 0 16px 34px rgba(0, 0, 0, 0.22);
}

.brand h1 {
    margin: 0;
    color: white;
    font-size: 1.08rem;
    line-height: 1.2;
}

.brand p {
    margin: 4px 0 0;
    color: rgba(255, 255, 255, 0.68);
    font-size: 0.86rem;
}

.tabs {
    display: grid;
    gap: 8px;
}

.tab-button {
    display: flex;
    align-items: center;
    gap: 11px;
    width: 100%;
    min-height: 48px;
    border: 1px solid transparent;
    border-radius: 8px;
    background: transparent;
    color: rgba(255, 255, 255, 0.72);
    cursor: pointer;
    padding: 10px 12px;
    text-align: left;
    transition: background 0.18s ease, border-color 0.18s ease, color 0.18s ease, transform 0.18s ease;
}

.tab-button:hover {
    border-color: var(--sidebar-line);
    background: rgba(255, 255, 255, 0.06);
    color: white;
}

.tab-button.active {
    border-color: rgba(184, 117, 61, 0.45);
    background: rgba(255, 255, 255, 0.1);
    color: white;
    font-weight: 800;
    box-shadow: inset 3px 0 0 var(--accent);
}

.tab-icon {
    position: relative;
    display: grid;
    place-items: center;
    flex: 0 0 28px;
    width: 28px;
    height: 28px;
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 8px;
    background: rgba(255, 255, 255, 0.08);
}

.tab-icon::before,
.tab-icon::after {
    content: "";
    position: absolute;
}

.icon-foundation::before {
    width: 15px;
    height: 10px;
    border: 2px solid #d9b07c;
    border-top-width: 4px;
    bottom: 7px;
}

.icon-concrete::before {
    width: 15px;
    height: 15px;
    border: 2px solid #8bd0c6;
    transform: rotate(45deg);
}

.icon-brick::before {
    width: 16px;
    height: 12px;
    background:
        linear-gradient(#d9b07c, #d9b07c) 0 50% / 100% 2px no-repeat,
        linear-gradient(#d9b07c, #d9b07c) 50% 0 / 2px 50% no-repeat,
        linear-gradient(#d9b07c, #d9b07c) 30% 100% / 2px 50% no-repeat;
    border: 2px solid #d9b07c;
    border-radius: 3px;
}

.icon-tile::before {
    width: 15px;
    height: 15px;
    border: 2px solid #8bd0c6;
    border-radius: 3px;
}

.icon-tile::after {
    width: 2px;
    height: 15px;
    background: #8bd0c6;
    transform: rotate(45deg);
}

.icon-paint::before {
    width: 14px;
    height: 14px;
    border-radius: 50% 50% 50% 4px;
    background: #d9b07c;
    transform: rotate(-45deg);
}

.panel {
    display: none;
}

.panel.active {
    display: block;
}

.panel-header {
    display: flex;
    align-items: flex-end;
    justify-content: space-between;
    gap: 16px;
    margin-bottom: 24px;
    border-bottom: 1px solid var(--line);
    padding-bottom: 18px;
}

.eyebrow {
    margin: 0 0 7px;
    color: var(--accent);
    font-size: 0.78rem;
    font-weight: 900;
    letter-spacing: 0;
    text-transform: uppercase;
}

.panel h2 {
    margin: 0;
    color: var(--ink);
    font-size: 2.15rem;
    line-height: 1.1;
}

.calculator-grid {
    display: grid;
    grid-template-columns: minmax(0, 1.18fr) minmax(280px, 0.82fr);
    align-items: start;
    gap: 22px;
}

.calculator-grid.wide {
    grid-template-columns: minmax(0, 1.42fr) minmax(300px, 0.78fr);
}

.form-card,
.result-card {
    border: 1px solid rgba(196, 204, 198, 0.86);
    border-radius: 8px;
    background: var(--surface-strong);
    box-shadow: var(--shadow-soft);
}

.form-card {
    display: grid;
    gap: 18px;
    padding: 24px;
}

.mini-section {
    display: grid;
    gap: 12px;
    border-bottom: 1px solid var(--line);
    padding-bottom: 18px;
}

.mini-section:last-of-type {
    border-bottom: 0;
}

.mini-section h3 {
    margin: 0;
    color: var(--primary-dark);
    font-size: 1.02rem;
}

.input-row {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 14px;
}

label {
    display: grid;
    gap: 8px;
    color: #2b3834;
    font-size: 0.92rem;
    font-weight: 760;
}

input {
    width: 100%;
    min-height: 46px;
    border: 1px solid var(--line-strong);
    border-radius: 8px;
    background: #fffefa;
    color: var(--ink);
    padding: 10px 12px;
    outline: none;
    transition: border-color 0.16s ease, box-shadow 0.16s ease, background 0.16s ease;
}

input::placeholder {
    color: #8b928e;
}

input:focus {
    border-color: var(--primary);
    background: white;
    box-shadow: 0 0 0 4px rgba(14, 111, 99, 0.13);
}

.actions {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    padding-top: 4px;
}

.primary-button,
.secondary-button {
    min-height: 46px;
    border-radius: 8px;
    cursor: pointer;
    padding: 10px 17px;
    font-weight: 850;
    transition: transform 0.18s ease, box-shadow 0.18s ease, background 0.18s ease, border-color 0.18s ease;
}

.primary-button {
    border: 1px solid var(--primary-dark);
    background: var(--primary);
    color: white;
    box-shadow: 0 12px 22px rgba(14, 111, 99, 0.24);
}

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

.secondary-button {
    border: 1px solid var(--line-strong);
    background: #fffefa;
    color: #56615c;
}

.secondary-button:hover {
    border-color: var(--primary);
    color: var(--primary-dark);
    transform: translateY(-1px);
}

.result-card {
    position: sticky;
    top: 16px;
    display: grid;
    gap: 12px;
    min-height: 210px;
    padding: 24px;
    background:
        linear-gradient(180deg, #ffffff 0%, #f7fbf9 100%);
}

.result-label {
    display: inline-flex;
    align-items: center;
    width: fit-content;
    border: 1px solid rgba(184, 117, 61, 0.28);
    border-radius: 8px;
    background: var(--accent-soft);
    color: #8d5125;
    padding: 6px 9px;
    font-size: 0.72rem;
    font-weight: 900;
    text-transform: uppercase;
}

.result-card.stacked {
    align-content: start;
}

.result-list {
    display: grid;
    gap: 9px;
}

.result-list p {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 14px;
    min-height: 38px;
    margin: 0;
    border-bottom: 1px solid rgba(217, 223, 218, 0.82);
    padding-bottom: 9px;
}

.result-list p:last-child {
    border-bottom: 0;
    border-radius: 8px;
    background: rgba(14, 111, 99, 0.08);
    margin-top: 2px;
    padding: 10px 11px;
}

.result-list span {
    color: var(--muted);
}

.result-list strong {
    color: var(--ink);
    text-align: right;
}

.result-list p:last-child strong {
    color: var(--success);
    font-size: 1.08rem;
}

@media (max-width: 900px) {
    .app-shell {
        grid-template-columns: 1fr;
        width: min(760px, calc(100% - 24px));
        margin: 12px auto;
    }

    .sidebar {
        gap: 18px;
    }

    .tabs {
        grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
        overflow-x: visible;
    }

    .tab-button {
        justify-content: flex-start;
        min-width: 0;
    }

    .content {
        min-height: auto;
        padding: 22px;
    }

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

    .result-card {
        position: static;
    }
}

@media (max-width: 640px) {
    .app-shell {
        width: min(100% - 16px, 520px);
        margin: 8px auto;
        gap: 14px;
    }

    .sidebar,
    .content {
        border-radius: 8px;
    }

    .sidebar {
        padding: 16px;
    }

    .brand {
        padding-bottom: 16px;
    }

    .brand-mark {
        width: 50px;
        height: 50px;
    }

    .brand h1 {
        font-size: 1rem;
    }

    .tabs {
        grid-template-columns: 1fr;
        gap: 8px;
    }

    .tab-button {
        gap: 9px;
        min-height: 48px;
        padding: 9px 10px;
        font-size: 0.94rem;
    }

    .tab-icon {
        width: 26px;
        height: 26px;
        flex: 0 0 26px;
    }

    .content {
        padding: 16px;
    }

    .panel-header {
        align-items: flex-start;
        flex-direction: column;
        margin-bottom: 18px;
        padding-bottom: 14px;
    }

    .panel h2 {
        font-size: 1.62rem;
    }

    .form-card,
    .result-card {
        padding: 16px;
    }

    .input-row {
        grid-template-columns: 1fr;
    }

    .actions {
        display: grid;
        grid-template-columns: 1fr;
    }

    .primary-button,
    .secondary-button {
        width: 100%;
    }

    .result-list p {
        align-items: flex-start;
        flex-direction: column;
        gap: 3px;
    }

    .result-list strong {
        text-align: left;
    }
}