/* ============================================
   Brick Calculator - Styles
   Modern, premium construction calculator
   ============================================ */

/* ---------- CSS Variables ---------- */
:root {
    --font-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;

    /* Colors - Warm construction theme */
    --color-bg: #f0ebe3;
    --color-bg-alt: #faf8f5;
    --color-surface: #ffffff;
    --color-primary: #d4700a;
    --color-primary-hover: #b85e08;
    --color-primary-light: #fff3e6;
    --color-primary-glow: rgba(212, 112, 10, 0.15);
    --color-secondary: #2d3436;
    --color-text: #2d3436;
    --color-text-muted: #636e72;
    --color-text-light: #b2bec3;
    --color-border: #dfe6e9;
    --color-border-light: #eef1f3;
    --color-success: #00b894;
    --color-accent: #e17055;
    --color-highlight: #ffeaa7;
    --color-result-bg: #f8f5f0;

    /* Shadows */
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.06), 0 1px 2px rgba(0, 0, 0, 0.04);
    --shadow-md: 0 4px 14px rgba(0, 0, 0, 0.08), 0 2px 6px rgba(0, 0, 0, 0.04);
    --shadow-lg: 0 10px 40px rgba(0, 0, 0, 0.1), 0 4px 14px rgba(0, 0, 0, 0.05);
    --shadow-glow: 0 0 30px rgba(212, 112, 10, 0.12);

    /* Borders */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 20px;

    /* Transitions */
    --transition-fast: 0.15s ease;
    --transition-base: 0.25s ease;
    --transition-slow: 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

/* ---------- Reset & Base ---------- */
*,
*::before,
*::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-primary);
    color: var(--color-text);
    background-color: var(--color-bg);
    line-height: 1.7;
    font-size: 15px;
    min-height: 100vh;
}

/* ---------- Container ---------- */
.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

/* ---------- Header ---------- */
.site-header {
    background: rgba(255, 255, 255, 0.85);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--color-border-light);
    position: sticky;
    top: 0;
    z-index: 100;
    transition: box-shadow var(--transition-base);
}

.site-header:hover {
    box-shadow: var(--shadow-sm);
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 64px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    text-decoration: none;
    color: var(--color-text);
    font-weight: 700;
    font-size: 20px;
    transition: transform var(--transition-fast);
}

.logo:hover {
    transform: scale(1.02);
}

.logo-icon {
    font-size: 28px;
    animation: brickBounce 3s ease-in-out infinite;
}

@keyframes brickBounce {

    0%,
    100% {
        transform: translateY(0);
    }

    50% {
        transform: translateY(-3px);
    }
}

.logo-text {
    background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.header-nav {
    display: flex;
    gap: 8px;
}

.nav-link {
    text-decoration: none;
    color: var(--color-text-muted);
    font-size: 14px;
    font-weight: 500;
    padding: 8px 16px;
    border-radius: var(--radius-sm);
    transition: all var(--transition-fast);
}

.nav-link:hover {
    color: var(--color-primary);
    background: var(--color-primary-light);
}

/* Language Switcher */
.language-switcher {
    margin-left: 8px;
}

.language-switcher select {
    padding: 8px 28px 8px 12px;
    border: 1.5px solid var(--color-border);
    border-radius: var(--radius-sm);
    font-family: var(--font-primary);
    font-size: 13px;
    font-weight: 500;
    color: var(--color-text);
    background: var(--color-surface);
    cursor: pointer;
    outline: none;
    transition: all var(--transition-fast);
    -webkit-appearance: none;
    -moz-appearance: none;
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='10' height='6'%3E%3Cpath d='M0 0l5 6 5-6z' fill='%23636e72'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 10px center;
}

.language-switcher select:hover {
    border-color: var(--color-primary);
    background: var(--color-primary-light);
}

.language-switcher select:focus {
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px var(--color-primary-glow);
}

@media (max-width: 768px) {
    .language-switcher {
        margin-left: 0;
        width: 100%;
    }

    .language-switcher select {
        width: 100%;
    }
}

/* ---------- Hero ---------- */
.hero {
    background: linear-gradient(135deg, #d4700a 0%, #e17055 50%, #f39c12 100%);
    padding: 60px 0 50px;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    inset: 0;
    background: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%23ffffff' fill-opacity='0.05'%3E%3Cpath d='M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
    opacity: 0.6;
}

.hero-content {
    position: relative;
    text-align: center;
}

.hero h1 {
    font-size: clamp(2rem, 5vw, 3.2rem);
    font-weight: 800;
    color: #fff;
    margin-bottom: 14px;
    letter-spacing: -0.5px;
    text-shadow: 0 2px 10px rgba(0, 0, 0, 0.15);
}

.hero-subtitle {
    font-size: clamp(1rem, 2.5vw, 1.15rem);
    color: rgba(255, 255, 255, 0.92);
    max-width: 600px;
    margin: 0 auto;
    font-weight: 400;
    line-height: 1.6;
}

/* ---------- Main Layout ---------- */
.main-layout {
    display: grid;
    grid-template-columns: 420px 1fr;
    gap: 40px;
    padding-top: 40px;
    padding-bottom: 80px;
    align-items: start;
}

@media (max-width: 960px) {
    .main-layout {
        grid-template-columns: 1fr;
        gap: 32px;
    }
}

/* ---------- Calculator Panel ---------- */
.calculator-panel {
    position: sticky;
    top: 88px;
}

@media (max-width: 960px) {
    .calculator-panel {
        position: static;
    }
}

.calculator-card {
    background: var(--color-surface);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-lg), var(--shadow-glow);
    overflow: hidden;
    border: 1px solid rgba(212, 112, 10, 0.08);
}

/* ---------- Calculator Sections ---------- */
.calc-section {
    border-bottom: 1px solid var(--color-border-light);
}

.calc-section:last-child {
    border-bottom: none;
}

.section-toggle {
    display: flex;
    align-items: center;
    gap: 10px;
    width: 100%;
    padding: 16px 20px;
    background: none;
    border: none;
    cursor: pointer;
    font-family: var(--font-primary);
    font-size: 14px;
    font-weight: 600;
    color: var(--color-text);
    text-align: left;
    transition: all var(--transition-fast);
    user-select: none;
}

.section-toggle:hover {
    background: var(--color-primary-light);
}

.section-toggle.active {
    background: linear-gradient(135deg, rgba(212, 112, 10, 0.06), rgba(212, 112, 10, 0.02));
}

.section-icon {
    font-size: 18px;
    line-height: 1;
}

.section-title {
    flex: 1;
}

.toggle-arrow {
    font-size: 12px;
    color: var(--color-text-muted);
    transition: transform var(--transition-base);
}

.section-toggle.active .toggle-arrow {
    transform: rotate(0deg);
}

.section-toggle:not(.active) .toggle-arrow {
    transform: rotate(-90deg);
}

/* Section Content */
.section-content {
    padding: 0 20px 20px;
    display: flex;
    flex-direction: column;
    gap: 14px;
    max-height: 1200px;
    overflow: hidden;
    transition: max-height var(--transition-slow), padding var(--transition-slow), opacity var(--transition-base);
    opacity: 1;
}

.section-content.collapsed {
    max-height: 0;
    padding-top: 0;
    padding-bottom: 0;
    opacity: 0;
    pointer-events: none;
}

/* ---------- Field Groups ---------- */
.field-group {
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.field-group label {
    font-size: 12px;
    font-weight: 600;
    color: var(--color-text-muted);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.input-with-unit {
    display: flex;
    align-items: center;
    border: 1.5px solid var(--color-border);
    border-radius: var(--radius-sm);
    overflow: hidden;
    background: var(--color-bg-alt);
    transition: all var(--transition-fast);
}

.input-with-unit:focus-within {
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px var(--color-primary-glow);
    background: var(--color-surface);
}

.input-with-unit input {
    flex: 1;
    min-width: 0;
    padding: 10px 14px;
    border: none;
    outline: none;
    font-family: var(--font-primary);
    font-size: 15px;
    font-weight: 500;
    color: var(--color-text);
    background: transparent;
    -moz-appearance: textfield;
}

.input-with-unit input::-webkit-outer-spin-button,
.input-with-unit input::-webkit-inner-spin-button {
    -webkit-appearance: none;
    margin: 0;
}

.input-with-unit input::placeholder {
    color: var(--color-text-light);
    font-weight: 400;
}

.unit-select {
    padding: 10px 8px;
    border: none;
    outline: none;
    font-family: var(--font-primary);
    font-size: 13px;
    font-weight: 600;
    color: var(--color-primary);
    background: transparent;
    cursor: pointer;
    min-width: 52px;
    text-align: center;
    border-left: 1px solid var(--color-border-light);
    transition: background var(--transition-fast);
    -webkit-appearance: none;
    -moz-appearance: none;
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='10' height='6'%3E%3Cpath d='M0 0l5 6 5-6z' fill='%23d4700a'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 6px center;
    padding-right: 18px;
}

.unit-select:hover {
    background-color: var(--color-primary-light);
}

.unit-static {
    padding: 10px 14px;
    font-size: 13px;
    font-weight: 600;
    color: var(--color-primary);
    border-left: 1px solid var(--color-border-light);
    background: transparent;
    white-space: nowrap;
}

/* Dropdowns (full-width selects) */
.field-group>select {
    padding: 10px 14px;
    border: 1.5px solid var(--color-border);
    border-radius: var(--radius-sm);
    font-family: var(--font-primary);
    font-size: 15px;
    font-weight: 500;
    color: var(--color-text);
    background: var(--color-bg-alt);
    cursor: pointer;
    outline: none;
    transition: all var(--transition-fast);
    -webkit-appearance: none;
    -moz-appearance: none;
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='7'%3E%3Cpath d='M0 0l6 7 6-7z' fill='%23636e72'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 14px center;
    padding-right: 36px;
}

.field-group>select:focus {
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px var(--color-primary-glow);
    background-color: var(--color-surface);
}

/* Result fields */
.result-field .input-with-unit {
    background: var(--color-result-bg);
    border-color: rgba(212, 112, 10, 0.15);
}

.result-input {
    font-weight: 600 !important;
    color: var(--color-primary) !important;
}

.highlight-result .input-with-unit {
    background: linear-gradient(135deg, #fff3e6, #ffeaa7);
    border-color: var(--color-primary);
    border-width: 2px;
}

.result-highlight {
    font-size: 18px !important;
    font-weight: 700 !important;
    color: var(--color-primary) !important;
}

/* Mortar hidden */
.mortar-hidden {
    display: none;
}

.mortar-hidden.mortar-visible {
    display: flex;
    flex-direction: column;
    gap: 14px;
    animation: fadeIn var(--transition-base) ease;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(-8px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* ---------- Content Panel ---------- */
.content-panel {
    padding: 0;
}

.content-section {
    background: var(--color-surface);
    border-radius: var(--radius-lg);
    padding: 32px;
    margin-bottom: 24px;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--color-border-light);
    transition: box-shadow var(--transition-base);
}

.content-section:hover {
    box-shadow: var(--shadow-md);
}

.content-section h2 {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--color-text);
    margin-bottom: 16px;
    letter-spacing: -0.3px;
    position: relative;
    padding-bottom: 12px;
}

.content-section h2::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 50px;
    height: 3px;
    background: linear-gradient(90deg, var(--color-primary), var(--color-accent));
    border-radius: 2px;
}

.content-section p {
    margin-bottom: 14px;
    color: var(--color-text);
    line-height: 1.8;
}

.content-section p:last-child {
    margin-bottom: 0;
}

.content-section ul,
.content-section ol {
    margin: 14px 0;
    padding-left: 24px;
}

.content-section li {
    margin-bottom: 8px;
    line-height: 1.7;
    color: var(--color-text);
}

/* Formula box */
.formula-box {
    background: linear-gradient(135deg, #2d3436, #636e72);
    color: #ffeaa7;
    padding: 20px 28px;
    border-radius: var(--radius-md);
    margin: 20px 0;
    font-size: 16px;
    font-weight: 500;
    overflow-x: auto;
    box-shadow: var(--shadow-md);
}

.formula-box code {
    font-family: 'SF Mono', 'Fira Code', 'Cascadia Code', monospace;
    white-space: nowrap;
}

/* Variable list */
.variable-list li {
    list-style: none;
    padding-left: 8px;
    border-left: 3px solid var(--color-primary);
    margin-left: -24px;
    padding-left: 20px;
    margin-bottom: 6px;
}

/* ---------- FAQ ---------- */
.faq-section h2 {
    margin-bottom: 24px;
}

.faq-item {
    border: 1px solid var(--color-border-light);
    border-radius: var(--radius-md);
    margin-bottom: 12px;
    overflow: hidden;
    transition: all var(--transition-base);
}

.faq-item:hover {
    border-color: var(--color-primary);
    box-shadow: 0 2px 12px var(--color-primary-glow);
}

.faq-item[open] {
    border-color: var(--color-primary);
    background: var(--color-primary-light);
}

.faq-item summary {
    padding: 16px 20px;
    cursor: pointer;
    list-style: none;
    display: flex;
    align-items: center;
    gap: 12px;
    transition: background var(--transition-fast);
    user-select: none;
}

.faq-item summary::-webkit-details-marker {
    display: none;
}

.faq-item summary::before {
    content: '▸';
    font-size: 14px;
    color: var(--color-primary);
    transition: transform var(--transition-base);
    flex-shrink: 0;
}

.faq-item[open] summary::before {
    transform: rotate(90deg);
}

.faq-item summary:hover {
    background: var(--color-primary-light);
}

.faq-item summary h3 {
    font-size: 15px;
    font-weight: 600;
    color: var(--color-text);
    margin: 0;
    line-height: 1.5;
}

.faq-answer {
    padding: 0 20px 20px;
    animation: fadeIn var(--transition-base) ease;
}

.faq-answer p,
.faq-answer ol,
.faq-answer ul {
    font-size: 14px;
    line-height: 1.7;
}

/* ---------- Footer ---------- */
.site-footer {
    background: var(--color-secondary);
    color: rgba(255, 255, 255, 0.7);
    padding: 32px 0;
}

.footer-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 16px;
}

.footer-text {
    font-size: 13px;
}

.footer-nav {
    display: flex;
    gap: 20px;
}

.footer-nav a {
    color: rgba(255, 255, 255, 0.6);
    text-decoration: none;
    font-size: 13px;
    font-weight: 500;
    transition: color var(--transition-fast);
}

.footer-nav a:hover {
    color: #fff;
}

/* ---------- Responsive ---------- */
@media (max-width: 640px) {
    .container {
        padding: 0 16px;
    }

    .hero {
        padding: 40px 0 32px;
    }

    .header-nav {
        display: none;
    }

    .main-layout {
        padding-top: 24px;
        padding-bottom: 48px;
        gap: 24px;
    }

    .content-section {
        padding: 24px 20px;
    }

    .content-section h2 {
        font-size: 1.25rem;
    }

    .section-toggle {
        padding: 14px 16px;
    }

    .section-content {
        padding: 0 16px 16px;
    }

    .footer-inner {
        flex-direction: column;
        text-align: center;
    }
}

/* ---------- Scrollbar ---------- */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: var(--color-bg);
}

::-webkit-scrollbar-thumb {
    background: var(--color-text-light);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--color-text-muted);
}

/* ---------- Selection ---------- */
::selection {
    background: var(--color-primary);
    color: #fff;
}