/* ==========================================================================
   Botum Sakor Energy Co., Ltd. — Corporate One-Page Website
   Author: design handoff build
   Description: Self-contained stylesheet. Only external dependency is the
                web font stack (system fonts, no network request required).
   ========================================================================== */

/* ---------------------------------------------------------------
   1. Design Tokens (CSS Custom Properties)
   Change these values to re-theme the whole page.
   --------------------------------------------------------------- */
:root {
  --navy:    #07293d;   /* primary dark background            */
  --blue:    #0b5e7d;   /* deep teal-blue                     */
  --teal:    #0fa3a3;   /* accent 1 (blue-green)              */
  --green:   #28b487;   /* accent 2 (green)                   */
  --light:   #f4fafb;   /* page background                    */
  --text:    #22333b;   /* body text                          */
  --muted:   #5c7079;   /* secondary text                     */
  --white:   #ffffff;

  --grad-accent: linear-gradient(90deg, var(--teal), var(--green));
  --grad-dark:   linear-gradient(135deg, var(--navy) 0%, #0a4a5e 60%, #0e6d63 100%);
  --shadow-sm:   0 6px 24px rgba(10, 80, 100, .08);
  --shadow-md:   0 16px 40px rgba(10, 80, 100, .16);
  --shadow-lg:   0 18px 46px rgba(10, 80, 100, .18);

  --radius-sm:   12px;
  --radius-md:   16px;
  --radius-lg:   20px;
  --nav-height:  80px;
}

/* ---------------------------------------------------------------
   2. Reset & Base
   --------------------------------------------------------------- */
* { margin: 0; padding: 0; box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  font-family: "Helvetica Neue", Arial, "Segoe UI", Roboto, sans-serif;
  font-size: 16px;
  line-height: 1.8;
  color: var(--text);
  background: var(--light);
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

img { max-width: 100%; display: block; border: 0; }
a   { text-decoration: none; color: inherit; }
ul  { list-style: none; }

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

/* Accessibility: visible focus ring for keyboard users */
a:focus-visible,
button:focus-visible {
  outline: 2px solid var(--green);
  outline-offset: 3px;
  border-radius: 4px;
}

/* Screen-reader-only helper */
.sr-only {
  position: absolute;
  width: 1px; height: 1px;
  padding: 0; margin: -1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
  border: 0;
}

/* Scroll offset so the fixed header does not cover section headings */
section[id] { scroll-margin-top: var(--nav-height); }

/* ---------------------------------------------------------------
   3. Header / Navigation
   --------------------------------------------------------------- */
.site-header {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  padding: 18px 0;
  transition: background .35s ease, padding .35s ease, box-shadow .35s ease;
}

.site-header.is-scrolled {
  padding: 10px 0;
  background: rgba(6, 32, 48, .93);
  -webkit-backdrop-filter: blur(10px);
  backdrop-filter: blur(10px);
  box-shadow: 0 2px 20px rgba(0, 0, 0, .28);
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav__logo img { height: 44px; width: auto; }

.nav__links {
  display: flex;
  gap: 36px;
}

.nav__links a {
  position: relative;
  padding: 4px 0;
  font-size: 14px;
  font-weight: 500;
  letter-spacing: 1.6px;
  text-transform: uppercase;
  color: rgba(255, 255, 255, .88);
  transition: color .3s ease;
}

.nav__links a::after {
  content: "";
  position: absolute;
  left: 0; bottom: 0;
  width: 0; height: 2px;
  background: var(--grad-accent);
  transition: width .3s ease;
}

.nav__links a:hover,
.nav__links a:focus-visible { color: var(--white); }

.nav__links a:hover::after,
.nav__links a:focus-visible::after { width: 100%; }

@media (max-width: 860px) {
  .nav__links { display: none; }
}

/* ---------------------------------------------------------------
   4. Hero
   --------------------------------------------------------------- */
.hero {
  position: relative;
  height: 100vh;
  min-height: 640px;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  color: var(--white);
  overflow: hidden;
}

.hero__bg {
  position: absolute;
  inset: 0;
  background: var(--navy); /* fallback while images load */
}

/* Background slideshow — cross-fading slides with a slow Ken-Burns zoom.
   --hero-slides must match the number of .hero__slide elements. */
.hero__bg {
  --hero-slides: 2;
}

.hero__slide {
  position: absolute;
  inset: 0;
  background-position: center;
  background-size: cover;
  background-repeat: no-repeat;
  opacity: 0;
  transform: scale(1.06);
  transition: opacity 1.6s ease;
  will-change: opacity, transform;
}

.hero__slide.is-active {
  opacity: 1;
  animation: kenburns 9s ease-in-out infinite alternate;
}

@keyframes kenburns {
  to { transform: scale(1.15) translateY(-14px); }
}

.hero__dots {
  position: absolute;
  bottom: 92px;
  left: 50%;
  transform: translateX(-50%);
  z-index: 3;
  display: flex;
  gap: 12px;
}

.hero__dot {
  width: 34px;
  height: 4px;
  padding: 0;
  border: 0;
  border-radius: 2px;
  background: rgba(255, 255, 255, .35);
  cursor: pointer;
  transition: background .3s ease;
}

.hero__dot:hover,
.hero__dot:focus-visible { background: rgba(255, 255, 255, .65); }

.hero__dot.is-active { background: var(--white); }

.hero::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(
    180deg,
    rgba(5, 32, 48, .60) 0%,
    rgba(7, 45, 60, .38) 45%,
    rgba(4, 26, 38, .80) 100%
  );
}

.hero__content {
  position: relative;
  z-index: 2;
  padding: 0 24px;
  animation: fadeUp 1.2s ease both;
}

@keyframes fadeUp {
  from { opacity: 0; transform: translateY(36px); }
  to   { opacity: 1; transform: none; }
}

.hero__tag {
  display: inline-block;
  max-width: 100%;
  margin-bottom: 28px;
  padding: 8px 24px;
  font-size: 12px;
  letter-spacing: 5px;
  white-space: nowrap;
  color: var(--white);
  border: 1px solid rgba(255, 255, 255, .45);
  border-radius: 999px;
  background: rgba(15, 163, 163, .18);
}

@media (max-width: 480px) {
  .hero__tag {
    font-size: 10px;
    letter-spacing: 2.5px;
    padding: 7px 16px;
  }
}

.hero__title {
  font-size: clamp(36px, 6vw, 74px);
  font-weight: 800;
  letter-spacing: 4px;
  line-height: 1.18;
  overflow-wrap: break-word;
  text-shadow: 0 4px 30px rgba(0, 0, 0, .45);
}

@media (max-width: 480px) {
  .hero__title { letter-spacing: 1.5px; }
}

.hero__title span {
  background: linear-gradient(90deg, #3fe0c5, #8ef0a8);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.hero__sub {
  max-width: 760px;
  margin: 22px auto 0;
  font-size: clamp(14px, 1.7vw, 18px);
  letter-spacing: 2px;
  color: rgba(255, 255, 255, .85);
}

.hero__scroll {
  position: absolute;
  bottom: 34px; left: 50%;
  z-index: 2;
  transform: translateX(-50%);
  font-size: 11px;
  letter-spacing: 4px;
  color: rgba(255, 255, 255, .7);
  animation: bob 2s infinite;
}

@keyframes bob {
  50% { transform: translate(-50%, 10px); }
}

/* ---------------------------------------------------------------
   5. Stats Bar
   --------------------------------------------------------------- */
.stats {
  padding: 64px 0;
  color: var(--white);
  background: var(--grad-dark);
}

.stats__grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(210px, 1fr));
  gap: 36px;
  text-align: center;
}

.stat__num {
  font-size: clamp(32px, 4vw, 50px);
  font-weight: 800;
  background: linear-gradient(90deg, #3fe0c5, #8ef0a8);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.stat__label {
  margin-top: 8px;
  font-size: 13px;
  letter-spacing: 1.4px;
  text-transform: uppercase;
  color: rgba(255, 255, 255, .82);
}

/* ---------------------------------------------------------------
   6. Generic Section / Section Heading
   --------------------------------------------------------------- */
.section { padding: 96px 0; }

.section__head {
  margin-bottom: 60px;
  text-align: center;
}

.section__eyebrow {
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 5px;
  text-transform: uppercase;
  color: var(--teal);
}

.section__title {
  margin-top: 12px;
  font-size: clamp(27px, 3.4vw, 40px);
  font-weight: 800;
  letter-spacing: 2px;
  color: var(--navy);
}

.section__bar {
  width: 64px; height: 4px;
  margin: 22px auto 0;
  border-radius: 2px;
  background: var(--grad-accent);
}

.section--dark .section__title { color: var(--white); }

/* ---------------------------------------------------------------
   7. About
   --------------------------------------------------------------- */
/* About — text only, no accompanying image.
   Constrained line length keeps long English paragraphs comfortable to read. */
.about__text--full {
  max-width: 880px;
  margin: 0 auto;
}

.about__text p {
  margin-bottom: 22px;
  font-size: 16.5px;
  color: #33474f;
}

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

/* Highlight cards */
.highlights {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(230px, 1fr));
  gap: 22px;
  margin-top: 56px;
}

.highlight {
  padding: 28px 26px;
  background: var(--white);
  border-radius: var(--radius-md);
  border-top: 3px solid transparent;
  box-shadow: var(--shadow-sm);
  transition: transform .3s ease, box-shadow .3s ease, border-color .3s ease;
}

.highlight:hover {
  transform: translateY(-6px);
  border-top-color: var(--teal);
  box-shadow: var(--shadow-md);
}

.highlight__value {
  font-size: 26px;
  font-weight: 800;
  color: var(--teal);
}

.highlight h3 {
  margin: 6px 0 8px;
  font-size: 17px;
  color: var(--navy);
}

.highlight p {
  font-size: 14px;
  line-height: 1.7;
  color: var(--muted);
}

/* ---------------------------------------------------------------
   8. Project — two large stacked figures
   --------------------------------------------------------------- */
.project { background: #eaf5f4; }

.project__figures {
  display: flex;
  flex-direction: column;
  gap: 48px;
  max-width: 1160px;
  margin: 0 auto;
}

.project__figure {
  border-radius: var(--radius-lg);
  overflow: hidden;
  background: var(--white);
  box-shadow: var(--shadow-lg);
  transition: transform .35s ease, box-shadow .35s ease;
}

.project__figure:hover {
  transform: translateY(-6px);
  box-shadow: 0 26px 60px rgba(10, 80, 100, .22);
}

.project__figure img {
  width: 100%;
  height: auto;
  display: block;
}

/* Caption bar under each image */
.project__figure-caption {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 20px 28px;
  border-top: 3px solid transparent;
  border-image: var(--grad-accent) 1;
  background: var(--white);
}

.project__figure-caption b {
  font-size: 17px;
  letter-spacing: 1.2px;
  color: var(--navy);
}

.project__figure-caption span {
  font-size: 14px;
  letter-spacing: .4px;
  color: var(--muted);
}

@media (max-width: 700px) {
  .project__figures { gap: 30px; }
  .project__figure-caption { padding: 16px 18px; }
}

/* ---------------------------------------------------------------
   9. Gallery
   --------------------------------------------------------------- */
.gallery { background: var(--navy); }

/* Gallery — 8 items. 4 columns desktop / 2 tablet / 1 mobile = no orphan tiles. */
.gallery__grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 18px;
}

@media (max-width: 1100px) {
  .gallery__grid { grid-template-columns: repeat(3, 1fr); }
}

@media (max-width: 820px) {
  .gallery__grid { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 520px) {
  .gallery__grid { grid-template-columns: 1fr; }
}

.gallery__item {
  position: relative;
  height: 240px;
  border-radius: var(--radius-md);
  overflow: hidden;
}

@media (max-width: 820px) {
  .gallery__item { height: 200px; }
}

.gallery__item img {
  width: 100%; height: 100%;
  object-fit: cover;
  transition: transform .5s ease;
}

.gallery__item:hover img { transform: scale(1.08); }

.gallery__caption {
  position: absolute;
  left: 0; right: 0; bottom: 0;
  padding: 44px 18px 14px;
  font-size: 13.5px;
  letter-spacing: .6px;
  color: var(--white);
  background: linear-gradient(transparent, rgba(4, 26, 38, .88));
}

/* ---------------------------------------------------------------
   10. Vision / Closing
   --------------------------------------------------------------- */
.vision {
  padding: 96px 0;
  text-align: center;
  color: var(--white);
  background: linear-gradient(135deg, #0a4a5e, var(--navy));
}

.vision__title {
  font-size: clamp(25px, 3.2vw, 36px);
  font-weight: 800;
  letter-spacing: 2px;
}

.vision__text {
  max-width: 820px;
  margin: 20px auto 0;
  font-size: 16.5px;
  color: rgba(255, 255, 255, .82);
}

/* ---------------------------------------------------------------
   11. Contact
   --------------------------------------------------------------- */
.contact { background: #eaf5f4; }

/* Single address card, centred. The grid still supports 2 columns
   (1 column under 700 px) if a second contact point is added later. */
.contact__grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 26px;
  max-width: 900px;
  margin: 0 auto;
}

.contact__grid > :only-child {
  grid-column: 1 / -1;
  max-width: 460px;
  margin: 0 auto;
}

@media (max-width: 700px) {
  .contact__grid { grid-template-columns: 1fr; }
}

.contact__card {
  padding: 38px 32px;
  text-align: center;
  background: var(--white);
  border-radius: 18px;
  border-top: 3px solid transparent;
  box-shadow: 0 8px 28px rgba(10, 80, 100, .10);
  transition: transform .3s ease, box-shadow .3s ease, border-color .3s ease;
}

.contact__card:hover {
  transform: translateY(-6px);
  border-top-color: var(--teal);
  box-shadow: var(--shadow-md);
}

.contact__icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 56px; height: 56px;
  margin: 0 auto 18px;
  border-radius: 50%;
  color: var(--teal);
  background: linear-gradient(135deg, rgba(15, 163, 163, .14), rgba(40, 180, 135, .20));
}

.contact__label {
  margin-bottom: 10px;
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 2.4px;
  text-transform: uppercase;
  color: var(--navy);
}

.contact__value {
  font-size: 16px;
  font-style: normal;
  line-height: 1.75;
  color: #33474f;
}

.contact__value--address { font-size: 16px; }

/* Email/phone link styling — kept in place so a second contact
   card with a mailto: or tel: link can be dropped back in later
   without any CSS changes. */
.contact__value a {
  color: var(--blue);
  font-weight: 600;
  word-break: break-word;
  border-bottom: 2px solid rgba(15, 163, 163, .35);
  transition: color .3s ease, border-color .3s ease;
}

.contact__value a:hover,
.contact__value a:focus-visible {
  color: var(--teal);
  border-bottom-color: var(--teal);
}

/* ---------------------------------------------------------------
   12. Documents dropdown panel
   Anchored directly beneath the "Documents" nav item.
   --------------------------------------------------------------- */
.nav__doc { position: relative; }

/* Active trigger state */
.nav__links a.is-open {
  color: var(--white);
}
.nav__links a.is-open::after { width: 100%; }

.doc-panel {
  position: absolute;
  top: calc(100% + 16px);
  right: 0;
  z-index: 120;
  width: 340px;
  padding: 18px;
  text-align: left;
  color: var(--text);
  background: var(--white);
  border-radius: 14px;
  box-shadow: 0 20px 50px rgba(4, 26, 38, .30);
  animation: docPanelIn .22s ease both;
}

/* Small arrow pointing up at the nav item */
.doc-panel::before {
  content: "";
  position: absolute;
  top: -7px;
  right: 26px;
  width: 14px; height: 14px;
  background: var(--white);
  transform: rotate(45deg);
  border-radius: 2px;
}

@keyframes docPanelIn {
  from { opacity: 0; transform: translateY(-8px); }
  to   { opacity: 1; transform: none; }
}

/* Panel header */
.doc-panel__head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 12px;
  padding-bottom: 12px;
  border-bottom: 1px solid rgba(10, 80, 100, .10);
}

.doc-panel__title {
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 2px;
  text-transform: uppercase;
  color: var(--navy);
}

.doc-panel__close {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 26px; height: 26px;
  padding: 0;
  color: #6b7f88;
  background: transparent;
  border: 0;
  border-radius: 50%;
  cursor: pointer;
  transition: color .25s ease, background .25s ease;
}

.doc-panel__close:hover,
.doc-panel__close:focus-visible {
  color: var(--navy);
  background: rgba(10, 80, 100, .08);
}

/* Document list */
.doc-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.doc-item {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 11px 12px;
  border: 1px solid rgba(10, 80, 100, .12);
  border-radius: 10px;
  background: #f7fbfa;
  transition: border-color .25s ease, background .25s ease;
}

.doc-item:hover {
  border-color: rgba(15, 163, 163, .45);
  background: #eef8f6;
}

.doc-item__icon {
  display: flex;
  align-items: center;
  justify-content: center;
  flex: 0 0 36px;
  width: 36px; height: 36px;
  border-radius: 9px;
  color: var(--teal);
  background: linear-gradient(135deg, rgba(15, 163, 163, .14), rgba(40, 180, 135, .22));
}

.doc-item__body {
  flex: 1;
  min-width: 0;
}

.doc-item__title {
  display: block;
  font-size: 14px;
  line-height: 1.4;
  color: var(--navy);
}

.doc-item__meta {
  display: block;
  margin-top: 1px;
  font-size: 11.5px;
  letter-spacing: .3px;
  color: var(--muted);
}

.doc-item__action {
  display: flex;
  align-items: center;
  justify-content: center;
  flex: 0 0 32px;
  width: 32px; height: 32px;
  border-radius: 50%;
  color: var(--teal);
  background: rgba(15, 163, 163, .10);
  transition: background .25s ease, color .25s ease;
}

.doc-item__action:hover,
.doc-item__action:focus-visible {
  color: var(--white);
  background: var(--grad-accent);
}

/* Empty state */
.doc-empty {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
  padding: 24px 16px;
  text-align: center;
  color: var(--muted);
  border: 1px dashed rgba(10, 80, 100, .20);
  border-radius: 10px;
  background: #f7fbfa;
}

.doc-empty svg { color: rgba(15, 163, 163, .55); }

.doc-empty span {
  font-size: 13px;
  letter-spacing: .2px;
}

/* Mobile: panel spans the viewport width minus margins */
@media (max-width: 860px) {
  .doc-panel {
    right: -12px;
    width: min(320px, calc(100vw - 32px));
  }
}

/* ---------------------------------------------------------------
   13. Footer

   --------------------------------------------------------------- */
.site-footer {
  padding: 34px 0;
  font-size: 12.5px;
  letter-spacing: 1.2px;
  text-align: center;
  color: rgba(255, 255, 255, .6);
  background: #04161f;
}

.site-footer img {
  height: 30px;
  margin: 0 auto 14px;
  filter: brightness(0) invert(1);
  opacity: .92;
}

/* ---------------------------------------------------------------
   14. Reduced Motion — respect user accessibility preference
   --------------------------------------------------------------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: .001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .001ms !important;
  }
  .hero__bg { transform: none; }
}

/* ---------------------------------------------------------------
   15. Print
   --------------------------------------------------------------- */
@media print {
  .site-header, .hero__scroll { display: none; }
  .hero { height: auto; min-height: 0; padding: 60px 0; color: #000; }
  .hero__bg { display: none; }
  body { background: #fff; }
}

/* ---------------------------------------------------------------
   16. Reveal-on-scroll (progressive enhancement, driven by main.js)
   Only applied when JS is available, so content is never hidden.
   --------------------------------------------------------------- */
.reveal {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity .7s ease, transform .7s ease;
}
.reveal.is-visible {
  opacity: 1;
  transform: none;
}